HVAC Error Codes: Complete Guide
HVAC fault codes are the diagnostic language your furnace, air conditioner, heat pump, or mini-split uses to tell you what's wrong. Every major brand — Carrier, Trane, Lennox, Goodman, York, Daikin, Rheem, Mitsubishi, Fujitsu — uses its own numbering system, which makes troubleshooting across brands a challenge without a reference.
This hub indexes all 538 HVAC error code guides on this site. Use the brand sections below to jump to your equipment, or search your specific code number across the full table.
Most HVAC error codes fall into one of these categories: ignition failure (no flame, lockout), pressure switch (blocked vent, inducer motor), temperature sensor (thermistor open/short), limit switch (overheating, restricted airflow), communication loss (thermostat-to-board), or board failure (control or blower module).
Tip: Search your exact brand and code together, for example "Carrier error code 13" or "Trane furnace pressure switch fault".
538
Total Guides
11
Brands Covered
309
Brand-Specific Guides
246
General HVAC Guides
Common HVAC Error Code Patterns
| Code Type | What It Means | Typical Fix |
|---|---|---|
| 1-4 flashes | Ignition failure / lockout | Check flame sensor, gas valve, igniter |
| 3-6 flashes | Pressure switch fault | Check vent, condensate drain, inducer motor |
| E1 / E2 | Sensor failure (thermistor) | Replace temperature sensor, check wiring |
| Code 13 / 14 | Limit switch / overheat | Clean filter, check airflow, blower motor |
| Communication loss | Thermostat / board link lost | Check wiring, replace thermostat, replace board |
| HP code | Heat pump specific faults | Check reversing valve, defrost board, outdoor sensor |
Carrier Error Codes (72 guides)
| Guide | Description | Fix |
|---|---|---|
| Best Furnace Igniter Replacement: Universal and Brand-Specific Picks | Choose a furnace igniter replacement by matching style, voltage, bracket, and brand fit before ordering a universal or OEM part. | Fix → |
| Bryant Furnace Error Codes | Bryant furnace code guide for LED flashes, two-digit faults, Evolution diagnostics, Carrier-shared boards, ignition, limit, and pressure-switch checks. | Fix → |
| Carrier 11 Error Code - No Ignition Furnace Lockout | Carrier fault code 11 means no ignition. Check gas supply, hot surface igniter resistance, flame sensor signal, burner condition, and gas valve output. | Fix → |
| Carrier 12 Error Code - Blower Runs After Heat | Carrier 12 means the blower kept running after post-purge. Check high-limit trips, airflow, filter, blower capacitor, and control relay. | Fix → |
| Carrier 13 Error Code — Limit Switch Lockout Fix | Carrier error code 13 means limit-switch lockout from overheating. Check airflow, filter restriction, blower speed, limit switch, and heat exchanger risk. | Fix → |
| Carrier 13 Soft Lockout — What's Different from Hard Lockout | Carrier code 13 is a soft lockout. Compare it with hard lockout code 31, check ignition and airflow causes, and reset only after the fault clears. | Fix → |
| Carrier 14 Error Code - Ignition Lockout | Carrier 14 means ignition lockout after repeated failed trials. Check the igniter, flame sensor, gas supply, inducer, pressure switch, and wiring. | Fix → |
| Carrier 21 Error Code — Gas Heating Lockout Fix | Carrier error code 21 signals a gas heating lockout — the furnace failed to ignite after multiple attempts. Learn the exact steps to diagnose and reset it. | Fix → |
| Carrier 23 Error Code - Draft Safeguard Switch Fault | Carrier 23 means the draft safeguard switch did not prove draft. Check vent blockage, inducer speed, pressure tubing, condensate, and switch rating. | Fix → |
| Carrier 24 Error Code - Secondary Voltage Fuse Open | Carrier 24 means the 24V control fuse opened. Check thermostat wiring, accessories, zone valves, relay coils, transformer output, and board shorts. | Fix → |
| Carrier 22 Error Code - LSOM Stall Fault on Single-Stage Furnaces | Carrier error code 22 means an LSOM stall fault. Check motor startup, capacitor, wiring, board output, and blower or inducer load. | Fix → |
| Carrier Error Code 24 — Secondary Voltage Fuse Open | Carrier fault code 24 means the 3-amp secondary fuse opened. Find the low-voltage short, thermostat wiring fault, or contactor coil issue first. | Fix → |
| Carrier 24ACC Air Conditioner Error Codes | Carrier 24ACC guide for AC flash codes, high- and low-pressure trips, compressor protection, thermistors, contactors, and board checks. | Fix → |
| Carrier 24ANA Heat Pump Error Codes | Carrier 24ANA heat-pump fault guide for Performance Series LED codes, pressure trips, defrost faults, sensors, and board checks. | Fix → |
| Carrier 25 Error Code - Flame Sense Fault | Carrier 25 means a false or unexpected flame signal. Check the flame sensor rod, ceramic insulator, gas valve leakage, grounding, and wiring. | Fix → |
| Carrier 31 Error Code — Pressure Switch Fix | Carrier 31 pressure-switch guide for inducer draft, hoses, condensate traps, vent blockages, manometer checks, and part decisions. | Fix → |
| Carrier 32 Error Code - Pressure Switch Stuck Closed | Carrier 32 means the pressure switch reads closed before inducer startup. Check tubing water, switch contacts, wiring shorts, and the correct setpoint. | Fix → |
| Carrier 34 Error Code - Ignition Proving Failure | Carrier 34 means ignition proved briefly then failed. Check flame sensor signal, igniter, gas pressure, burner ground, wiring, and heat exchanger safety. | Fix → |
| Carrier 33 Error Code - Limit Switch Open | Carrier 33 means the furnace limit circuit opened during heat. Check airflow, filter, blower capacitor, rollout switches, flue, and heat exchanger. | Fix → |
| Carrier 40MAQ / 40MVC Mini Split Error Codes - Communication, Sensor, and Protection Faults | Carrier 40MAQ and 40MVC mini-split codes for E1 communication, thermistor faults, pressure protection, discharge temperature, and fan errors. | Fix → |
| Carrier 41 Error Code — Blower Motor Fault Fix | Carrier code 41 guide for ECM blower motor faults, module power, harness checks, wheel drag, control-board calls, and furnace airflow. | Fix → |
| Carrier 42 Error Code - Inducer Motor Fault | Carrier code 42 inducer-motor guide for seized draft motors, blocked flues, condensate restrictions, pressure switches, and IFC board checks. | Fix → |
| Carrier 43 Error Code — Rollout Switch Open Fix | Carrier 43 rollout-switch guide for flame rollout, blocked flues, inducer draft, gas pressure, heat exchanger risk, and manual resets. | Fix → |
| Carrier 44 Error Code - Open Igniter Circuit | Carrier code 44 open-igniter guide for cracked hot-surface igniters, loose harnesses, failed board relays, and wrong replacement igniters. | Fix → |
| Carrier 45 Error Code - IFC Control Board Fault | Carrier code 45 IFC fault guide for failed control boards, unstable voltage, wiring shorts, surge damage, and board replacement decisions. | Fix → |
| Carrier 46 Error Code - IFC Board Self-Diagnosis Fault | Carrier code 46 IFC self-diagnosis guide for low-voltage shorts, flame-sensor wiring, surge damage, failed boards, and model checks. | Fix → |
| Carrier 48 Error Code - Induced Draft Motor Lockout | Carrier code 48 inducer-lockout guide for failed draft motors, weak capacitors, blocked flues, pressure switches, hoses, and relay checks. | Fix → |
| Carrier 48XLC Packaged Unit Error Codes | Carrier 48XLC packaged-unit fault guide for pressure trips, ignition faults, economizer issues, sensors, airflow, and board checks. | Fix → |
| Carrier Error Code 51 — Control Fault (Secondary) | Carrier furnace code 51 points to a secondary control fault. Check pressure switches, stage-two gas valve wiring, inducer speed, and the IFC board. | Fix → |
| Carrier 52 Error Code - Repeated High-Limit Soft Lockout | Carrier code 52 high-limit soft-lockout guide for dirty filters, blocked returns, blower faults, weak capacitors, and limit-switch decisions. | Fix → |
| Carrier 54 Error Code - Low Pressure Switch Soft Lockout | Carrier code 54 low-pressure-switch guide for clogged condensate traps, cracked hoses, weak inducer motors, failed switches, and vent checks. | Fix → |
| Carrier 56 Error Code - Induced Draft IFC Fault | Carrier code 56 induced-draft fault guide for condensate blockages, pressure-switch hoses, failed switches, inducer motors, and IFC boards. | Fix → |
| Carrier 58 Error Code - Flame Sense Fault | Carrier code 58 flame-sense guide for dirty flame rods, bad sensor position, unstable gas pressure, wiring faults, and heat-exchanger risk. | Fix → |
| Carrier 58CVA Furnace Error Codes | Carrier 58CVA furnace guide for flash codes, pressure switches, ignition lockouts, limit trips, flame sensing, inducer faults, and resets. | Fix → |
| Carrier 58MVB Furnace Error Codes | Carrier 58MVB furnace flash-code guide for pressure switch, limit, flame-sense, inducer, igniter, ECM blower, and gas-valve faults. | Fix → |
| Carrier 58UX Furnace Error Codes | Carrier 58UX furnace guide for LED flash codes, pressure switches, limit trips, flame-sense faults, polarity errors, and lockouts. | Fix → |
| Carrier Error Code 61 — Rollout Switch Lockout | Carrier code 61 rollout-switch guide for flame rollout, cracked heat exchangers, blocked flues, inducer faults, gas pressure, and CO risk. | Fix → |
| Carrier Error Code 65 — Inducer Motor Fault | Carrier furnace error code 65: inducer motor fault causes, diagnosis, and repair for Carrier Performance and Infinity furnaces. | Fix → |
| Carrier Error Code 66 — Pressure Switch Fault | Carrier furnace error code 66: pressure switch fault causes, diagnosis steps, and repair for Carrier gas furnaces. | Fix → |
| Carrier AquaSnap Chiller Fault Codes — 30RB/30RQ Guide | Carrier AquaSnap 30RB and 30RQ chiller fault codes for i-Vue and Pro-Dialog controllers: alarms, safety shutdowns, and troubleshooting steps. | Fix → |
| Carrier Chiller Alarm Codes - 30XA, 30XV, 30HXC, 19XR | Carrier chiller alarm guide for 30XA, 30XV, 30HXC, and 19XR units: ComfortLink history, pressure trips, sensors, oil, and resets. | Fix → |
| Carrier 30XA Chiller Fault Codes | Carrier 30XA chiller fault guide for air-cooled alarms, pressure faults, flow trips, sensors, compressors, fans, and controls. | Fix → |
| Carrier AC E3 Error Code: IPM Module Fault Diagnosis and Fix | Carrier E3 points to an IPM fault. Check condenser airflow, voltage, refrigerant charge, compressor windings, and board damage before replacement. | Fix → |
| Carrier Furnace Error Code 13 — Limit Circuit Lockout Fix | Carrier error code 13 means limit circuit lockout after repeated high-limit trips. It auto-resets after 3 hours. Here's what caused it and how to fix it. | Fix → |
| Carrier Furnace Error Code 31 — Pressure Switch Open Fix | Carrier Furnace Error Code 31 - Pressure Switch Open Fix: likely causes, checks, and repair decisions before replacing parts. | Fix → |
| Carrier Code 33 Limit or Rollout Fault | Carrier code 33 guide for limit-switch and rollout faults, airflow, filters, blower speed, gas pressure, heat exchangers, and resets. | Fix → |
| Carrier E3 Error Code - Inverter Heat Protection Fault | Carrier E3 inverter-protection guide for dirty condenser coils, failed outdoor fan motors, low refrigerant charge, IPM boards, and capacitors. | Fix → |
| Carrier Furnace Error Code 13 Limit Lockout | Carrier code 13 guide for limit-switch lockout, overheating, airflow restrictions, code 33 differences, blower checks, filters, and safety limits. | Fix → |
| Carrier Furnace E1 Error Code - Infinity Communication Fault | Carrier furnace E1 communication guide for ABCD wiring, Infinity thermostats, indoor boards, outdoor boards, long wire runs, and surge damage. | Fix → |
| Carrier Furnace Error Codes — Complete Guide | Carrier furnace error codes: all flash codes with meanings, causes, and fixes for every Carrier gas furnace. | Fix → |
| Carrier Greenspeed Heat Pump Error Codes: Complete Guide | Carrier Greenspeed variable speed heat pump error codes and fault diagnostics. Infinity system fault codes, causes, and technician fixes. | Fix → |
| Carrier Geothermal Error Codes - Low Pressure, Freeze, ECM | Decode Carrier geothermal low-pressure, high-pressure, freeze protection, condensate, ECM blower, water-temperature, and Infinity communication faults. | Fix → |
| Carrier Heat Pump E1 Error Code — Causes & Fix | Carrier heat-pump E1 guide for indoor/outdoor communication faults, low-voltage wiring, polarity, surge damage, boards, and resets. | Fix → |
| Carrier Heat Pump E4 Error Code — Causes & Fix | Diagnose Carrier Heat Pump E4 Error Code - Causes & Fix: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| Carrier Heat Pump E5 Error Code — Defrost Fault: Causes & Fix | What Carrier heat pump E5 means, why defrost fails, and how to fix E5 error codes on Carrier heat pump systems. | Fix → |
| Carrier Heat Pump E6 Error Code - Outdoor Temp Sensor Fault | What Carrier E6 means on a heat pump, why the outdoor temperature sensor fails, and how to diagnose and fix it. | Fix → |
| Carrier Infinity 24ACC6 Error Codes | Carrier Infinity 24ACC6 guide for pressure trips, thermistors, compressor protection, discharge sensors, communication faults, and board checks. | Fix → |
| Carrier Infinity Error 168 | Carrier Infinity 168 guide for system communication faults, ABCD bus wiring, thermostats, furnace boards, outdoor boards, and setup checks. | Fix → |
| Carrier Infinity Error 178 - Indoor to Outdoor Communication Fault | Carrier Infinity 178 means the indoor and outdoor units lost communication. Check low-voltage wiring, terminals, boards, and data-line continuity. | Fix → |
| Carrier Infinity Communication Error Codes | Carrier Infinity communication codes point to thermostat, indoor unit, outdoor unit, or bus faults. Check ABCD wiring, module power, and zoning. | Fix → |
| Carrier Infinity Error 179 Communication Fault | Carrier Infinity 179 guide for lost equipment communication, ABCD bus wiring, thermostat faults, furnace boards, fuses, and outdoor unit checks. | Fix → |
| Carrier Infinity Zoning System Error Codes — Complete Guide | Carrier Infinity zoning faults point to damper, zone sensor, ABCD bus, airflow, and control-board issues in communicating HVAC systems. | Fix → |
| Carrier Mini-Split E4 Discharge Temp Fault | Carrier mini-split E4 guide for compressor discharge temperature faults, refrigerant issues, dirty coils, fan problems, and thermistor checks. | Fix → |
| Carrier Mini-Split F0 Low Refrigerant Code | Carrier mini-split F0 guide for low refrigerant and leak-detection faults, shutdown steps, leak checks, pressure sensors, and HVAC technician repair. | Fix → |
| Carrier Mini-Split P4 Inverter Overheat | Carrier mini-split P4 means the inverter module overheated. Check coil airflow, outdoor fan, clearance, heat sink, wiring, and board faults. | Fix → |
| Carrier Rooftop Unit Error Codes | Carrier RTU guide for 48 and 50 Series flash codes, ignition lockouts, limit trips, pressure faults, economizer alarms, and control-board checks. | Fix → |
| Carrier VRF System Error Codes Guide | Carrier VRF error codes point to EEV, thermistor, compressor, pressure, communication, drain, and controller faults. | Fix → |
| Carrier WeatherMaker Rooftop Unit Error Codes: Complete Guide | Carrier WeatherMaker RTU error codes for 48 and 50 Series commercial rooftop units. Flash codes, fault descriptions, and technician-level fixes. | Fix → |
| Carrier Zone Controller Error Codes - Complete Guide | Carrier zone controller codes identify damper, zone sensor, ABCD bus, bypass, power, and communicating equipment faults. | Fix → |
| Carrier Infinity XC21 Error Codes | Carrier Infinity XC21 guide for low-pressure, high-pressure, communication, compressor-protection, outdoor fan, thermistor, and lockout faults. | Fix → |
| Furnace Blinking 3 Times — Cross-Brand Comparison Guide | Troubleshoot Furnace Blinking 3 Times - Cross-Brand Comparison Guide: likely causes, field checks, and repair decisions before replacing parts. | Fix → |
| How to Reset a Furnace After Lockout — Per-Brand Reset Procedures | How to Reset a Furnace After Lockout - Per-Brand Reset Procedures: likely causes, checks, and repair decisions before replacing parts. | Fix → |
Trane Error Codes (47 guides)
| Guide | Description | Fix |
|---|---|---|
| Best Furnace Igniter Replacement: Universal and Brand-Specific Picks | Choose a furnace igniter replacement by matching style, voltage, bracket, and brand fit before ordering a universal or OEM part. | Fix → |
| Furnace Blinking 3 Times — Cross-Brand Comparison Guide | Troubleshoot Furnace Blinking 3 Times - Cross-Brand Comparison Guide: likely causes, field checks, and repair decisions before replacing parts. | Fix → |
| How to Reset a Furnace After Lockout — Per-Brand Reset Procedures | How to Reset a Furnace After Lockout - Per-Brand Reset Procedures: likely causes, checks, and repair decisions before replacing parts. | Fix → |
| Trane 1 Flash Error Code — Causes & Fix | What Trane 1 flash means on a furnace LED, why it signals normal operation or lockout depending on model, and how to respond. | Fix → |
| Trane Error Code 126 — Ignition Lockout Fix | Trane code 126 guide for furnace hard lockout, ignition retries, flame sensing, gas valve checks, pressure switches, and XR80/XR95 resets. | Fix → |
| Trane 2 Flashes Error Code — Causes & Fix | Troubleshoot Trane 2 flashes on HVAC equipment with checks for power, airflow, sensors, ignition, safety circuits, and parts to price before service. | Fix → |
| Trane 3 Flashes Error Code — Pressure Switch Fault Fix | Trane 3-flash furnace guide for pressure switch faults, inducer draft, blocked hoses, condensate backup, vent checks, and reset limits. | Fix → |
| Trane 3 Flashes Pressure Switch Fault | Trane 3-flash guide for pressure switch faults, inducer checks, hose tracing, condensate drains, blocked vents, and differential pressure testing. | Fix → |
| Trane 4 Flashes Error Code - Open High Limit Fix | Trane 4 flashes means an open high-limit fault. Check filter restriction, blower speed, duct airflow, evaporator coil blockage, and the limit switch. | Fix → |
| Trane 4TCC4 Mini Split Error Codes — Causes & Fix | Trane 4TCC4 mini split error codes explained — what each code means, why it happens, and how to fix it. | Fix → |
| Trane 5 Flashes Error Code — Causes & Fix | Troubleshoot Trane 5 flashes on HVAC equipment with checks for power, airflow, sensors, ignition, safety circuits, and parts to price before service. | Fix → |
| Trane 6 Flashes Error Code — Causes & Fix | Trane 6-flash rollout guide for blocked flues, weak inducer motors, cracked heat exchangers, gas-valve issues, and manual-reset limits. | Fix → |
| Trane 7 Flashes Error Code — Gas Valve Circuit Fault Fix | Trane 7 flashes means a gas valve circuit fault or ignition lockout after multiple attempts. This guide covers diagnosis and fixes for Trane furnace Code 7. | Fix → |
| Trane 8 Flashes Error Code — Causes & Fix | Diagnose Trane 8 Flashes Error Code - Causes & Fix: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| Trane 9 Flashes Error Code — Causes & Fix | Diagnose Trane 9 Flashes Error Code - Causes & Fix: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| Trane CenTraVac Chiller Fault Codes — Common Faults Guide | Guide to Trane CenTraVac centrifugal chiller fault codes, what each fault means, and how to diagnose the most common problems. | Fix → |
| Trane Chiller Fault Codes — Complete Troubleshooting Guide | Trane chiller fault codes for CGAM, CVHE, RTHD, and Tracer CH530 series. What each alarm means and how to fix it. | Fix → |
| Trane ComfortR ER Error Code — Causes & Fix | What the Trane ComfortR ER error code means on a communicating system, why communication fails, and how to restore the link. | Fix → |
| Trane ComfortLink II Error Codes — Common Faults and Fixes | Guide to Trane ComfortLink II communicating system error codes, what each fault means, and how to diagnose and fix the most common problems. | Fix → |
| Trane ComfortLink II Thermostat Fault Codes | Trane ComfortLink II guide for communicating thermostat faults, code 79, code 80, code 81, control boards, wiring, and repair decisions. | Fix → |
| Trane AC E2 Error Code — Sensor and Communication Fault Fix | Trane AC E2 Error Code - Sensor and Communication Fault Fix: likely causes, checks, and repair decisions before replacing parts. | Fix → |
| Trane XV20i Error Code 79: Communicating Thermostat Fault Fix | Trane XV20i error code 79 means a communicating thermostat fault. Learn the causes, how to diagnose ComfortLink II wiring issues, and how to fix it fast. | Fix → |
| Trane XV20i Error Code 79 — Causes & Fix | Diagnose Trane XV20i Error Code 79 - Causes & Fix: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| Trane Furnace 2 Flashes Pressure Switch Code | Trane furnace 2-flash guide for stuck-closed pressure switches, manometer testing, inducer checks, condensate problems, and code 3 differences. | Fix → |
| Trane Heat Pump 1 Flash Error Code | Trane heat-pump 1-flash guide for lockout resets, outdoor fan checks, defrost faults, pressure trips, coil icing, and service decisions. | Fix → |
| Trane Furnace Error Codes — Complete Flash Code Guide | Trane furnace error codes: all LED flash codes explained with causes and repair steps for XR, XC, and S-Series furnaces. | Fix → |
| Trane Heat Pump E2 Error Code — Outdoor Coil Sensor Fault | What Trane heat pump E2 means, why the outdoor coil sensor fails, and how to fix it on Trane XR, XL, and XC heat pump systems. | Fix → |
| Trane Heat Pump Error Codes - Complete Troubleshooting Guide | Trane heat pump error codes explained for communicating, variable-speed, XV20i, XL20i, and conventional systems. | Fix → |
| Trane Precedent Rooftop Unit Error Codes: Complete Guide | Use this Trane Precedent Rooftop Unit Error Codes reference to match the code with likely causes, service checks, and repair decisions. | Fix → |
| Trane Rooftop Unit Fault 77 — High Pressure Cutout | Trane rooftop Fault 77 high-pressure guide for dirty condenser coils, failed fan motors, overcharge, pressure-switch testing, and RTU reset limits. | Fix → |
| Trane Rooftop Unit Error Codes: Common Faults Guide | Complete guide to Trane RTU fault codes for Precedent, YCD, and YCC series units. Flash codes, alphanumeric faults, and technician fixes. | Fix → |
| Trane S8X1 Furnace Error Codes — Flash Code Diagnostic Guide | Trane S8X1 flash codes identify ignition, pressure switch, flame, rollout, limit, and polarity faults on S8X1 gas furnaces. | Fix → |
| Trane TAM Air Handler Error Codes — Complete Guide | Trane TAM air handler codes identify blower, coil sensor, airflow, pressure, drain, and ComfortLink communication faults. | Fix → |
| Trane XV20i/XV18 Variable Speed Heat Pump Error Codes | Trane XV20i and XV18 variable speed heat pump error codes and fault diagnostics. ComfortLink II fault codes, causes, and technician fixes. | Fix → |
| Trane XE80 Furnace Error Codes — Fault Code Guide | Trane XE80 furnace error codes: flash code meanings and fixes for this popular 80% AFUE single-stage furnace still common in the field. | Fix → |
| Trane VRF System Error Codes Guide | Trane VRF codes identify communication, EEV, thermistor, pressure, compressor, drain, and outdoor-board faults. | Fix → |
| Trane XL16i Heat Pump Error Codes | Trane XL16i heat-pump guide for pressure trips, defrost faults, compressor protection, fan issues, thermistors, and ComfortLink alerts. | Fix → |
| Trane XL20i Variable Speed Error Codes — Complete Guide | Trane XL20i variable speed heat pump error codes: all fault codes for the XL20i inverter-driven system with causes and technician-level fixes. | Fix → |
| Trane XR13 Air Conditioner Error Codes | Trane XR13 guide for LED flash faults, high/low pressure trips, compressor protection, thermistors, charge loss, and anti-short-cycle delay. | Fix → |
| Trane XR14 Heat Pump Error Codes | Trane XR14 heat-pump guide for LED flash codes, pressure-switch trips, compressor protection, defrost faults, sensors, and low voltage. | Fix → |
| Trane XR15 Heat Pump Error Codes — Complete Guide | Trane XR15 heat pump error codes: all fault codes, flash sequences, causes, and fixes for the Trane XR15 two-stage heat pump. | Fix → |
| Trane XR80 Error Codes — Flash Code Quick Reference | Complete Trane XR80 flash code guide: what each LED pattern (1–9 flashes) means and how to fix common faults. | Fix → |
| Trane XR90 Furnace Error Codes — Fault Code Diagnostic Guide | Trane XR90 Furnace Error Codes - Fault Code Diagnostic Guide: likely causes, checks, and repair decisions before replacing parts. | Fix → |
| Trane XV20i Heat Pump Error Codes — Common Faults & Fixes | Complete guide to Trane XV20i error codes, what they mean, and how to diagnose and fix the most common faults. | Fix → |
| Trane XR95 Furnace Error Codes — Complete Guide | Trane XR95 furnace error codes: all LED flash codes for the 95% AFUE single-stage XR95, causes, and fixes. | Fix → |
| Trane XV80 Furnace Error Codes — Flash Code Diagnostic Guide | Trane XV80 flash codes identify ignition, pressure switch, flame, rollout, limit, and inducer faults on two-stage gas furnaces. | Fix → |
| Trane YSC Packaged Rooftop Error Codes | Trane YSC rooftop guide for ReliaTel faults, HP/LP lockouts, freeze protection, fan circuits, liquid-line sensors, and return-air sensors. | Fix → |
Lennox Error Codes (44 guides)
| Guide | Description | Fix |
|---|---|---|
| Best Furnace Igniter Replacement: Universal and Brand-Specific Picks | Choose a furnace igniter replacement by matching style, voltage, bracket, and brand fit before ordering a universal or OEM part. | Fix → |
| Furnace Blinking 3 Times — Cross-Brand Comparison Guide | Troubleshoot Furnace Blinking 3 Times - Cross-Brand Comparison Guide: likely causes, field checks, and repair decisions before replacing parts. | Fix → |
| How to Reset a Furnace After Lockout — Per-Brand Reset Procedures | How to Reset a Furnace After Lockout - Per-Brand Reset Procedures: likely causes, checks, and repair decisions before replacing parts. | Fix → |
| Lennox Error Code 292 — Ignition Failure Fix | Lennox 292 ignition-lockout guide for hot-surface igniters, flame sensors, gas valves, supply pressure, control boards, and resets. | Fix → |
| Lennox EL296V Furnace Error Codes | Lennox EL296V furnace guide for ignition, limit, pressure-switch, flame-sense, gas-valve, inducer, and ECM blower faults. | Fix → |
| Lennox Elite Furnace Error Codes | Lennox Elite furnace guide for SureLight flash codes, iComfort alerts, pressure switches, rollout trips, ignition faults, and blower errors. | Fix → |
| Lennox 103 Error Code — Causes & Fix | Troubleshoot Lennox 103 on HVAC equipment with checks for power, airflow, sensors, ignition, safety circuits, and parts to price before service. | Fix → |
| Lennox Error Code 111 — Causes & Fix | Troubleshoot Lennox error code 111 on HVAC equipment with checks for power, airflow, sensors, ignition, safety circuits, and parts to price before service. | Fix → |
| Lennox Error Code 114 — Causes & Fix | Diagnose Lennox Error Code 114 - Causes & Fix: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| Lennox 204 Error Code — Causes & Fix | Troubleshoot Lennox 204 on HVAC equipment with checks for power, airflow, sensors, ignition, safety circuits, and parts to price before service. | Fix → |
| Lennox Error Code 125 — Causes & Fix | What Lennox error code 125 means, why the pressure switch stays open at the end of heat speed, and how to fix it. | Fix → |
| Lennox Error Code 223 — Causes & Fix | Troubleshoot Lennox error code 223 on HVAC equipment with checks for power, airflow, sensors, ignition, safety circuits, and parts to price before service. | Fix → |
| Lennox Error Code 225 — Causes & Fix | Troubleshoot Lennox error code 225 on HVAC equipment with checks for power, airflow, sensors, ignition, safety circuits, and parts to price before service. | Fix → |
| Lennox Error Code 231 — Causes & Fix | What Lennox error code 231 means, why the rollout switch trips, and how to reset and repair it safely. | Fix → |
| Lennox Error Code 327 — Causes & Fix | Troubleshoot Lennox error code 327 on HVAC equipment with checks for power, airflow, sensors, ignition, safety circuits, and parts to price before service. | Fix → |
| Lennox Error Code 332 — Causes & Fix | What Lennox error code 332 means, why the limit device opens, and how to diagnose and fix restricted airflow. | Fix → |
| Lennox Error Code 411 Ignition Proving Fault | Lennox 411 guide for ignition proving faults, flame-sensor signal, igniter checks, gas-pressure symptoms, lockout resets, and service limits. | Fix → |
| Lennox Error Code 412 — Inducer Motor Fault (Detailed Guide) | Lennox Error Code 412 - Inducer Motor Fault (Detailed Guide): likely causes, checks, and repair decisions before replacing parts. | Fix → |
| Lennox Error Code 412 Limit Switch Fault | Lennox 412 guide for high-limit trips, overheating causes, airflow checks, filters, blower issues, iComfort/SLP faults, and reset limits. | Fix → |
| Lennox Error Code 414 — Gas Valve Circuit Fault Fix | Diagnose Lennox Error Code 414 - Gas Valve Circuit Fault Fix: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| Lennox Error Code 414 Rollout - Rollout Switch Fault | Diagnose Lennox 414 rollout faults: rollout switch continuity, flue restrictions, inducer draft, gas pressure, and reset decisions. | Fix → |
| Lennox Error Code 432 — Causes & Fix | Diagnose Lennox Error Code 432 - Causes & Fix: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| Lennox Error Code 434 — Outdoor Unit Communication Fault | Lennox Error Code 434 - Outdoor Unit Communication Fault: likely causes, checks, and repair decisions before replacing parts. | Fix → |
| Lennox Error Code 441 — Limit Device Fault | Lennox 441 limit-device guide for airflow, filters, blower speed, rollout switches, heat exchanger risk, and reset decisions. | Fix → |
| Lennox 540 Communication Fault | Lennox 540 means an iComfort device lost communication. Check thermostat, indoor unit, outdoor board, RS-bus wiring, and zoning modules. | Fix → |
| Lennox Error Code 540 — Causes & Fix | Diagnose Lennox Error Code 540 - Causes & Fix: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| Lennox Furnace Blink Codes — Complete Red Light Guide | Use this Lennox Furnace Blink Codes - Complete Red Light Guide reference to match the code with likely causes, service checks, and repair decisions. | Fix → |
| Lennox Furnace Error Codes — Complete Reference Guide | Lennox furnace error codes: all fault codes for G61, ML, EL, and SL series furnaces with causes and fixes. | Fix → |
| Lennox G60UHV Furnace Error Codes | Lennox G60UHV furnace flash-code guide for inducer speed, pressure switches, high-limit trips, SureLight ignition, blower faults, and boards. | Fix → |
| Lennox Harmony III Zoning System Error Codes — Complete Guide | Lennox Harmony III zoning system error codes: fault codes for the HCC3-8 zone control center, damper issues, thermostat faults, and fixes. | Fix → |
| Lennox Healthy Climate Error Codes — Complete Guide | Lennox Healthy Climate air quality system error codes: fault codes for HCF16, HCX20, HEPA systems, and ERV/HRV units with causes and fixes. | Fix → |
| Lennox iComfort Error Code 225 — Communication Fault Fix Guide | Lennox iComfort Error Code 225 - Communication Fault Fix Guide: likely causes, checks, and repair decisions before replacing parts. | Fix → |
| Lennox iComfort Code 31 Pressure Switch Fault | Lennox iComfort code 31 guide for pressure switch faults, inducer draft, blocked flues, hoses, condensate drains, resets, and part checks. | Fix → |
| Lennox iComfort EFO and Common Faults | Lennox iComfort EFO means excessive flame loss. Check flame sensing, gas pressure, ignition, condensate drainage, venting, and communicating controls. | Fix → |
| Lennox iHarmony Zoning Error Codes | Lennox iHarmony guide for zone-lost, damper, sensor, bypass, communication, and discharge-air limit faults in zoning systems. | Fix → |
| Lennox Mini Split Error Code E1 — Causes & Fix | Diagnose Lennox Mini Split Error Code E1 - Causes & Fix: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| Lennox ResolvePlus Rooftop Unit Error Codes: Complete Guide | Lennox ResolvePlus RTU error codes and fault diagnostics. Covers flash codes, communicating system faults, and technician-level troubleshooting. | Fix → |
| Lennox Rooftop Unit Error Codes: Technician Guide | Lennox rooftop unit code guide for LGH, LCH, LCA, and Strategos units: flash codes, ignition lockouts, pressure trips, blower faults, and resets. | Fix → |
| Lennox SL280UHV Error Codes | Lennox SL280UHV guide for SureLight codes, limit faults, igniter failures, flame-sense problems, pressure switches, filters, and blower issues. | Fix → |
| Lennox SLP98V Error Codes — Variable-Speed Furnace Fault Guide | Lennox SLP98V error codes: iComfort fault codes, flash codes, and variable-speed blower faults for the 98% AFUE SLP98V furnace. | Fix → |
| Lennox XC16 Air Conditioner Error Codes | Lennox XC16 guide for iComfort alerts, high/low pressure faults, fan errors, compressor protection, sensor faults, and board checks. | Fix → |
| Lennox XC21 Error Codes — Diagnostic Guide and Fixes | Use this Lennox XC21 Error Codes - Diagnostic Guide and Fixes reference to match the code with likely causes, service checks, and repair decisions. | Fix → |
| Lennox XP20 Heat Pump Fault Codes | Lennox XP20 iComfort fault codes for communication, inverter, sensor, pressure, defrost, and control-board problems on variable-capacity heat pumps. | Fix → |
| Lennox XP21 Heat Pump Error Codes - iComfort Fault Code Guide | Lennox XP21 Heat Pump Error Codes - iComfort Fault Code Guide: likely causes, checks, and repair decisions before replacing parts. | Fix → |
Goodman Error Codes (34 guides)
| Guide | Description | Fix |
|---|---|---|
| Amana Furnace Error Codes - Ignition, Pressure, Flame, and Limit Faults | Amana furnace codes identify ignition, pressure switch, flame sensor, limit, rollout, polarity, and control-board faults. | Fix → |
| Best Furnace Igniter Replacement: Universal and Brand-Specific Picks | Choose a furnace igniter replacement by matching style, voltage, bracket, and brand fit before ordering a universal or OEM part. | Fix → |
| Furnace Blinking 3 Times — Cross-Brand Comparison Guide | Troubleshoot Furnace Blinking 3 Times - Cross-Brand Comparison Guide: likely causes, field checks, and repair decisions before replacing parts. | Fix → |
| Goodman 1 Flash Error Code — What It Means | What Goodman 1 flash status LED means, why it indicates normal operation, and what to check if your furnace still isn't heating. | Fix → |
| Goodman 2 Flash Error Code — Causes & Fix | Troubleshoot Goodman 2 flashes on HVAC equipment with checks for power, airflow, sensors, ignition, safety circuits, and parts to price before service. | Fix → |
| Goodman 3 Flash Pressure Switch Fault | Goodman 3-flash guide for pressure switch faults, inducer draft, blocked venting, condensate traps, hoses, resets, and Amana/Daikin units. | Fix → |
| Goodman 4 Flash Error Code — Causes & Fix | Troubleshoot Goodman 4 flashes on HVAC equipment with checks for power, airflow, sensors, ignition, safety circuits, and parts to price before service. | Fix → |
| Goodman 7 Flash Ignition Lockout | Goodman 7-flash guide for ignition lockout, gas supply checks, igniter and flame-sensor testing, rollout safety, and reset limits. | Fix → |
| Goodman 6 Flash Error Code — Rollout Switch Open Fix | Goodman 6-flash rollout-switch guide for flame rollout, blocked flues, weak inducer draft, gas-pressure issues, and heat-exchanger safety. | Fix → |
| Goodman 5 Flash Error Code — Causes & Fix | Diagnose Goodman 5 Flash Error Code - Causes & Fix: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| Goodman Furnace 8 Flashes - Ignition Failure Lockout | Goodman 8 flashes means ignition failure lockout. Check the ignitor, flame sensor, gas pressure, pressure switch sequence, and inducer operation. | Fix → |
| Goodman 9 Flash Error Code — Causes & Fix | What Goodman 9 flash means, why reversed line/load power causes it, and how to fix the wiring safely. | Fix → |
| Amana / Goodman Furnace 3 Flash Error Code — Causes & Fix | Amana / Goodman Furnace 3 Flash Error Code - Causes & Fix: likely causes, checks, and repair decisions before replacing parts. | Fix → |
| Goodman ComfortNet Error Codes | Goodman ComfortNet guide for communicating furnace, heat-pump, air-handler, thermostat, bus-wiring, pressure-switch, and blower faults. | Fix → |
| Goodman EE2 Control Board Communication Fault | Goodman EE2 guide for communicating HVAC faults, wiring, power surges, 24VAC transformers, thermostat compatibility, and board checks. | Fix → |
| Goodman Furnace 2 Flashes — Pressure Switch Stuck Closed Fix | Goodman Furnace 2 Flashes - Pressure Switch Stuck Closed Fix: likely causes, checks, and repair decisions before replacing parts. | Fix → |
| Goodman Furnace 3 Flashes — Pressure Switch Open Fix | Goodman furnace 3-flash pressure-switch guide for condensate drains, pressure hoses, inducer motors, blocked vents, and switch testing. | Fix → |
| Goodman Furnace 4 Flashes — Open High Limit Switch Fix | Goodman Furnace 4 Flashes - Open High Limit Switch Fix: likely causes, checks, and repair decisions before replacing parts. | Fix → |
| Goodman Furnace 5 Flash Error Code - Flame Sensed With No Heat Call | Goodman 5 flashes means flame is sensed without a heat call. Inspect flame-sensor wiring, rod position, gas-valve leakage, and the control-board input. | Fix → |
| Goodman Furnace E1 Error Code — Causes & Fix | Diagnose Goodman Furnace E1 Error Code - Causes & Fix: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| Goodman Furnace E2 Flame Sense Fault | Goodman furnace E2 means a flame-sense fault on digital-display models. Clean the flame sensor, check grounding, gas ignition, and timing. | Fix → |
| Goodman Furnace E3 Draft Motor Fault | Goodman E3 guide for inducer startup, pressure-switch proofing, condensate blockage, flue restriction, hose leaks, and IFC output checks. | Fix → |
| Goodman Furnace EE2 Error Code — Causes & Fix | Diagnose Goodman Furnace EE2 Error Code - Causes & Fix: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| Goodman Furnace EF Error Code — Invalid Flame Signal | Diagnose Goodman Furnace EF Error Code - Invalid Flame Signal: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| Goodman Furnace Error Codes 1-8 | Goodman furnace 1-8 flash-code guide for pressure switch, rollout, limit, ignition, flame-sense, gas-valve, and control-board faults. | Fix → |
| Goodman Furnace Error Codes — All Flash Codes Explained | Use this Goodman Furnace Error Codes - All Flash Codes Explained reference to match the code with likely causes, service checks, and repair decisions. | Fix → |
| Goodman GMS80 Furnace Error Codes | Goodman GMS80 furnace guide for LED codes, pressure switches, limit trips, flame sensor faults, rollout switches, igniters, and blower issues. | Fix → |
| Goodman GMS96 Error Codes — Fault Code Guide | Goodman GMS96 furnace error codes: all flash codes for the popular 96% AFUE single-stage furnace with causes and fixes. | Fix → |
| Goodman GMSS96 Furnace Error Codes — Flash Code Diagnostic Guide | Goodman GMSS96 Furnace Error Codes - Flash Code Diagnostic Guide: likely causes, checks, and repair decisions before replacing parts. | Fix → |
| Goodman GPH Series Packaged Unit Error Codes: Complete Guide | Goodman GPH packaged heat pump error codes and fault diagnostics. Flash codes, fault descriptions, and technician-level troubleshooting steps. | Fix → |
| Goodman GSX13 Air Conditioner Error Codes | Goodman GSX13 guide for AC flash codes, pressure-switch trips, contactor faults, capacitor checks, fan problems, and control-board calls. | Fix → |
| Goodman GSZC18 Heat Pump Error Codes | Goodman GSZC18 guide for ComfortNet and LED faults, pressure lockouts, defrost-control errors, fan faults, board faults, and sensors. | Fix → |
| Goodman Heat Pump E1 Error Code — Pressure Switch Fault | What Goodman heat pump E1 means, why the pressure switch opens, and how to fix it on Goodman heat pump systems. | Fix → |
| How to Reset a Furnace After Lockout — Per-Brand Reset Procedures | How to Reset a Furnace After Lockout - Per-Brand Reset Procedures: likely causes, checks, and repair decisions before replacing parts. | Fix → |
York Error Codes (23 guides)
| Guide | Description | Fix |
|---|---|---|
| Furnace Blinking 3 Times — Cross-Brand Comparison Guide | Troubleshoot Furnace Blinking 3 Times - Cross-Brand Comparison Guide: likely causes, field checks, and repair decisions before replacing parts. | Fix → |
| How to Reset a Furnace After Lockout — Per-Brand Reset Procedures | How to Reset a Furnace After Lockout - Per-Brand Reset Procedures: likely causes, checks, and repair decisions before replacing parts. | Fix → |
| York 3 Flashes Error Code — Causes & Fix | Troubleshoot York 3 flashes on HVAC equipment with checks for power, airflow, sensors, ignition, safety circuits, and parts to price before service. | Fix → |
| York 2 Flashes Error Code — Causes & Fix | What York 2 flashes means on a furnace, why the pressure switch is stuck closed, and how to fix it. | Fix → |
| York 4 Flashes Error Code — Open Limit Device Fix | York 4 flashes means the high limit switch opened due to overheating. This guide covers every cause and fix for the York furnace 4-flash open limit fault. | Fix → |
| York Furnace 6 Flashes Error Code — Pressure Switch Fault Fix | York Furnace 6 Flashes Error Code - Pressure Switch Fault Fix: likely causes, checks, and repair decisions before replacing parts. | Fix → |
| York 5 Flashes Error Code — Causes & Fix | Troubleshoot York 5 flashes on HVAC equipment with checks for power, airflow, sensors, ignition, safety circuits, and parts to price before service. | Fix → |
| York 7 Flashes Error Code — Ignition Lockout Fix | York 7 flashes means ignition lockout after 3 failed attempts. This guide covers diagnosis and fixes for the York furnace 7-flash ignition lockout fault. | Fix → |
| York Affinity Series Packaged Unit Error Codes: Complete Guide | York Affinity packaged unit error codes and fault diagnostics. Flash codes, communicating system faults, and technician-level troubleshooting. | Fix → |
| York 8 Flashes Error Code — Causes & Fix | What 8 flashes on a York furnace means, why ignition lockout occurs, and how to diagnose and reset the system. | Fix → |
| York Chiller Fault Codes - YVAA, YVFA, YWHA, OptiView | York chiller fault guide for YVAA, YVFA, YWHA, YT, and OptiView controls: pressure trips, oil faults, VSD alarms, sensors, and reset limits. | Fix → |
| York Furnace Error Code E2 — Causes & Fix | Diagnose York Furnace Error Code E2 - Causes & Fix: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| York Furnace Error Code E3 - Pressure Switch Fix | York furnace E3 means the pressure switch is stuck closed. Check switch continuity, tubing, condensate in the inducer, wiring shorts, and reset. | Fix → |
| York Furnace E2 Pressure Switch Fault | York E2 furnace guide for pressure switch faults, blocked condensate drains, cracked hoses, inducer problems, vent restrictions, and switch tests. | Fix → |
| York Furnace Error Code E5 — High Limit Tripped | York furnace error code E5: high limit switch tripped causes, diagnosis steps, and fixes for York TM9V, TG9S, and compatible gas furnaces. | Fix → |
| York Furnace E4 Error Code — Ignition Failure | Diagnose York Furnace E4 Error Code - Ignition Failure: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| York Furnace Error Codes — Complete Guide | York furnace error codes: all flash codes and diagnostic codes for YP9C, TM9E, LX, and other York gas furnace models. | Fix → |
| York Mini Split Error Code E1 — Causes & Fix | Diagnose York Mini Split Error Code E1 - Causes & Fix: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| York Rooftop Unit Error Codes - Predator and ZF RTU | York RTU error-code guide for Predator, Affinity, and ZF rooftop units, including pressure lockouts, ignition faults, flame-sense errors, sensors, and blower faults. | Fix → |
| York TG9 Furnace Error Codes - Fault Code Guide | York TG9 furnace fault codes for pressure switch, limit, ignition, rollout, blower, control-board, and communication faults. | Fix → |
| York YCD Packaged Unit Error Codes | York YCD packaged-unit guide for pressure trips, ignition lockouts, fan faults, economizer issues, sensors, and control-board checks. | Fix → |
| York YSC Rooftop Unit Error Codes Guide | Complete York YSC series rooftop unit error codes. Covers all E-codes, P-codes, and flash codes with technician-level diagnostic steps. | Fix → |
| York YG2C Furnace Error Codes — Flash Code Diagnostic Guide | York YG2C flash codes identify ignition, pressure switch, flame, rollout, limit, and inducer faults on YG2C gas furnaces. | Fix → |
Daikin Error Codes (24 guides)
| Guide | Description | Fix |
|---|---|---|
| Daikin A3 Error Code: Drain Pan and Pump Fault | Daikin A3 points to a full drain pan, clogged condensate line, failed pump, float switch problem, or poor indoor-unit slope. | Fix → |
| Daikin C4 Error Code: Indoor Coil Sensor Fault | Daikin C4 means the indoor coil thermistor is out of range. Check sensor seating, connector corrosion, thermistor resistance, and PCB input. | Fix → |
| Daikin C9 Discharge Sensor Error | Daikin C9 guide for compressor discharge-temperature sensor faults, loose connectors, bad thermistors, refrigerant issues, and outdoor PCB checks. | Fix → |
| Daikin Chiller Fault Codes - EWAD, EWAQ, McQuay, and MicroTech Alarms | Daikin chiller alarm guide for EWAD, EWAQ, McQuay, iOM, MicroTech, high-pressure, low-pressure, compressor, oil, and freeze faults. | Fix → |
| Daikin E1 Error Code: Indoor Thermistor Fault | Daikin E1 points to an indoor temperature sensor fault. Check the thermistor, connector corrosion, indoor PCB input, moisture damage, and model match. | Fix → |
| Daikin E3 Error Code: Indoor Fan Motor Fault | Daikin E3 means the indoor fan speed is wrong or missing. Check wheel drag, coil buildup, motor feedback, wiring, and the indoor PCB. | Fix → |
| Daikin E7 Outdoor Fan Motor Error | Daikin E7 guide for outdoor fan motor faults, stalled blades, Hall feedback, motor windings, inverter-board output, connectors, and debris. | Fix → |
| Daikin E9 Error Code: Compressor Protection Fault | Daikin E9 points to compressor protection. Check refrigerant charge, outdoor coil airflow, compressor current, ambient limits, and inverter faults. | Fix → |
| Daikin F3 Error Code: Discharge Thermistor Fault | Daikin F3 points to the discharge temperature thermistor circuit. Test the sensor, connector, harness, and outdoor-board input before ordering parts. | Fix → |
| Daikin F9 Heat Exchanger Sensor Fault | Daikin F9 guide for indoor coil thermistor faults, loose sensor plugs, dislodged probes, PCB moisture, resistance tests, and sensor replacement. | Fix → |
| Daikin Fit Error Codes — Inverter Heat Pump Diagnostic Guide | Daikin Fit error codes identify inverter heat pump faults. Match E3, U4, L5, and sensor codes to service checks, parts, and repair decisions. | Fix → |
| Daikin H6 Error Code — Indoor Fan Motor Lock Fault Fix | Daikin H6 indoor fan guide for locked motors, blower obstructions, capacitors, Hall sensors, control boards, ice, and VRV/VRF checks. | Fix → |
| Daikin J3 Discharge Pipe Sensor Fault | Daikin J3 guide for discharge-pipe sensor faults, abnormal compressor temperature, thermistor testing, coil airflow, charge issues, and technician checks. | Fix → |
| Daikin L5 Error Code: Compressor Lock Fault | Daikin L5 means compressor startup failed or lock protection tripped. Check locked-rotor current, inverter output, wiring, and compressor condition. | Fix → |
| Daikin Mini Split Error Codes - E, U, F, A Faults | Daikin mini-split code guide for wall-mount and multi-zone systems: E, U, F, and A faults, thermistors, drains, communication, and reset checks. | Fix → |
| Daikin R-32 U4 Error Code: Communication Fault | Daikin R-32 U4 means indoor-outdoor communication failed. Check signal terminals, reversed wiring, cable damage, interference, and the inverter board. | Fix → |
| Daikin RXYQ VRV Error Codes: Commercial Fault Guide | Daikin RXYQ VRV faults cover pressure, EEV, compressor startup, refrigerant shortage, and F1/F2 transmission errors on commercial systems. | Fix → |
| Daikin U2 Error Code: Undervoltage Protection Fault | Daikin U2 means supply voltage dropped too low. Check utility voltage, wire size, disconnect terminals, contactors, and compressor startup load. | Fix → |
| Daikin U4 Error Code: Low-Pressure Refrigerant Fault | Daikin U4 on this guide points to low pressure or refrigerant flow trouble. Check leaks, service valves, restrictions, and the pressure sensor. | Fix → |
| Daikin U9 Error Code: High-Pressure Trip Fault | Daikin U9 points to high pressure. Check outdoor coil blockage, fan motor speed, refrigerant overcharge, and non-condensables in the circuit. | Fix → |
| Daikin VRV E7 Fan Motor Error Code | Daikin VRV E7 fan-motor guide for locked rotors, fan inverter boards, blades, harness checks, DC motor tests, and pro repair limits. | Fix → |
| Daikin VRV System Error Codes | Daikin VRV error-code guide for U, E, A, C, F, and H faults. Check communication wiring, sensors, refrigerant pressure, drains, boards, and fan motors. | Fix → |
| Daikin RXQ VRV System Error Codes (Outdoor Unit): Complete Guide | Daikin RXQ VRV outdoor unit error codes and fault diagnostics. U-series fault codes, causes, and technician-level troubleshooting. | Fix → |
| Daikin VRV/VRF U4 Communication Fault | Daikin VRV/VRF U4 guide for indoor-outdoor communication faults, F1/F2 wiring, termination resistors, PCB failures, power issues, and noise. | Fix → |
Rheem Error Codes (23 guides)
| Guide | Description | Fix |
|---|---|---|
| Best Furnace Igniter Replacement: Universal and Brand-Specific Picks | Choose a furnace igniter replacement by matching style, voltage, bracket, and brand fit before ordering a universal or OEM part. | Fix → |
| Furnace Blinking 3 Times — Cross-Brand Comparison Guide | Troubleshoot Furnace Blinking 3 Times - Cross-Brand Comparison Guide: likely causes, field checks, and repair decisions before replacing parts. | Fix → |
| How to Reset a Furnace After Lockout — Per-Brand Reset Procedures | How to Reset a Furnace After Lockout - Per-Brand Reset Procedures: likely causes, checks, and repair decisions before replacing parts. | Fix → |
| Rheem Classic Series Furnace Error Codes — Complete Guide | Rheem Classic and Classic Plus furnace error codes: all flash codes with meanings and repair steps for R801T, R96V, and Classic series models. | Fix → |
| Rheem Air Handler E1 Error Code — Causes & Fix | Diagnose Rheem Air Handler E1 Error Code - Causes & Fix: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| Rheem Furnace 2 Flashes — Pressure Switch Fault | Diagnose Rheem Furnace 2 Flashes - Pressure Switch Fault: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| Rheem Furnace 4 Flashes Limit Fault | Rheem furnace 4-flash guide for open high-limit faults, overheating, airflow restrictions, blower issues, filters, and reset limits. | Fix → |
| Rheem Furnace 3 Flashes Error Code — Causes & Fix | What Rheem 3 flashes means on a furnace, why the draft pressure switch faults, and how to fix it. | Fix → |
| Rheem Furnace 5 Flashes Error Code - Flame Sensor Fault Fix | Rheem Furnace 5 Flashes Error Code - Flame Sensor Fault Fix: likely causes, checks, and repair decisions before replacing parts. | Fix → |
| Rheem Furnace 6 Flashes - Rollout Switch Open Fix | Rheem furnace 6 flashes means a rollout switch trip. Check vent blockage, inducer draft, burner flame, gas pressure, and heat-exchanger safety. | Fix → |
| Rheem Furnace 7 Flashes Error Code — Causes & Fix | Troubleshoot Rheem 7 flashes on HVAC equipment with checks for power, airflow, sensors, ignition, safety circuits, and parts to price before service. | Fix → |
| Rheem Furnace 8 Flashes Error Code - Ignition Lockout | Rheem 8 flashes means ignition lockout. Clean the flame sensor, test the ignitor, verify gas pressure, and check gas-valve operation before resetting. | Fix → |
| Rheem Furnace 9 Flashes Error Code - Reversed Polarity Fix | What 9 flashes on a Rheem furnace means, why reversed polarity causes it, and how to correct the wiring. | Fix → |
| Rheem Furnace Error Code 57 — Causes & Fix | Diagnose Rheem Furnace Error Code 57 - Causes & Fix: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| Rheem Furnace Error Code 7 Flashes — Low Flame Signal Fix | What Rheem furnace error code 7 flashes means, why the flame signal is weak, and how to test the flame sensor, ground path, burners, and gas pressure. | Fix → |
| Rheem Furnace Error Codes - All Flash Codes Explained | Rheem furnace flash codes: what each blink pattern means on Classic, Classic Plus, and Prestige series furnaces. | Fix → |
| Rheem Heat Pump Error Codes | Rheem RA14, RA15, and RP15 heat pump fault codes. Decode E1, E2, E4, and E5 sensor, high-pressure, and low-pressure trips. | Fix → |
| Rheem RA13 Air Conditioner Error Codes | Rheem RA13 guide for high-pressure, low-pressure, compressor overload, control-board, thermistor, anti-short-cycle, and low-voltage faults. | Fix → |
| Rheem RA16 Heat Pump Error Codes | Rheem RA16 heat-pump guide for flash codes, pressure trips, defrost-board faults, thermistors, capacitors, contactors, and reversing valves. | Fix → |
| Rheem RGPS Furnace Error Codes — Flash Code Diagnostic Guide | Rheem RGPS flash codes identify ignition, pressure switch, rollout, flame, inducer, and limit faults on Classic Plus gas furnaces. | Fix → |
| Rheem RPH Series Packaged Unit Error Codes: Complete Guide | Use this Rheem RPH Series Packaged Unit Error Codes reference to match the code with likely causes, service checks, and repair decisions. | Fix → |
| Rheem Ruud Furnace Error Codes | Rheem and Ruud furnace flash and 2-digit codes for Classic, Prestige, and Endeavor units. Decode flame, pressure, limit, and blower faults. | Fix → |
| Rheem Water Heater Blinking Light Codes | Rheem blinking-light guide for pilot, thermopile, thermocouple, ECO switch, gas-control, and ignition faults before replacing water-heater parts. | Fix → |
Mitsubishi Error Codes (28 guides)
| Guide | Description | Fix |
|---|---|---|
| Mitsubishi City Multi P8 / E6 Error Codes — Causes & Fix | What Mitsubishi City Multi P8 and E6 commercial VRF error codes mean, why they trip, and how to diagnose and fix them. | Fix → |
| Mitsubishi PEX City Multi Error Codes | Mitsubishi PEX City Multi indoor-unit guide for P1, P2, P4, P5, P6, P8, drain, thermistor, float-switch, and coil-freeze faults. | Fix → |
| Mitsubishi E1 Communication Fault | Mitsubishi E1 means indoor and outdoor units lost communication. Check S-terminal wiring, zone wiring, power supplies, and indoor or outdoor PCBs. | Fix → |
| Mitsubishi E3 Error Code — Indoor Fan Motor Fault Fix | Mitsubishi E3 mini-split guide for indoor fan motor faults, blower wheel jams, Hall sensor feedback, PCB checks, and frozen coils. | Fix → |
| Mitsubishi E4 Error Code — Causes & Fix | Troubleshoot Mitsubishi E4 on HVAC equipment with checks for power, airflow, sensors, ignition, safety circuits, and parts to price before service. | Fix → |
| Mitsubishi E5 Error Code - Drain Pump or Float Switch Fault | Mitsubishi mini-split E5 points to a condensate drain problem. Check the drain pan, lift pump, float switch, drain hose slope, and blocked tubing. | Fix → |
| Mitsubishi E6 AC Error Code — Causes & Fix | Diagnose Mitsubishi E6 AC Error Code - Causes & Fix: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| Mitsubishi Mini Split E6 Error Code Fix | Diagnose Mitsubishi Mini Split E6 Error Code Fix: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| Mitsubishi E7 Error Code — Refrigerant Cycle Fault | Mitsubishi mini-split Error Code E7 indicates a refrigerant cycle abnormality. Learn causes, diagnostic steps, and fixes for Mitsubishi E7. | Fix → |
| Mitsubishi Mini Split E1 Indoor Thermistor Fault | Mitsubishi E1 guide for indoor room thermistor faults, sensor resistance checks, wiring issues, MSZ/MXZ units, and control-board decisions. | Fix → |
| Mitsubishi Mini Split E9 Error Code - Outdoor Thermistor Fault | Mitsubishi mini-split E9 points to an outdoor thermistor fault. Test TH3 resistance, inspect the connector, check wiring, and rule out PCB input failure. | Fix → |
| Mitsubishi Mini Split E6 Communication Fault | Mitsubishi E6 means the indoor and outdoor units lost communication. Check S-Bus wiring, fuses, boards, and interference before replacing parts. | Fix → |
| Mitsubishi Mini Split Error Codes — Complete Guide | Mitsubishi mini split error codes: all E, U, and P codes explained with causes and fixes for Mr. Slim and M-Series units. | Fix → |
| Mitsubishi Mini Split P8 Overheat Fault | Mitsubishi P8 means the outdoor heat exchanger is overheating. Check coil airflow, fan operation, clearance, refrigerant issues, and thermistors. | Fix → |
| Mitsubishi Mini Split U4 Error Code — Causes & Fix | What Mitsubishi U4 means on mini split systems, why the outdoor thermistor faults, and how to diagnose and fix it. | Fix → |
| Mitsubishi Mini-Split U0 Error Code: Refrigerant Shortage | Mitsubishi U0 guide for refrigerant-shortage faults, leak signs, pressure-sensor issues, service-valve checks, and certified HVAC repair decisions. | Fix → |
| Mitsubishi Mr. Slim Error Codes: Complete Guide | Complete Mitsubishi Mr. Slim error code guide. Covers all P, E, and U-series fault codes for commercial Mr. Slim PUHZ, PEA, and PKAA series units. | Fix → |
| Mitsubishi P1 Error Code - Mini Split Freeze Protection | Mitsubishi P1 error code guide for mini-split freeze protection: check filters, coil ice, indoor fan speed, thermistor seating, refrigerant charge, and leaks. | Fix → |
| Mitsubishi P4 Error Code — Drain System Fault: Causes & Fix | What Mitsubishi P4 means, why the drain system faults, and how to fix P4 on Mitsubishi mini-split systems. | Fix → |
| Mitsubishi P5 Error Code - Drain Pump Fault | Mitsubishi P5 mini-split drain pump fault guide for condensate pumps, float switches, blocked drain tubing, overflow risk, and safe repair checks. | Fix → |
| Mitsubishi Mini Split P6 Error Code Fix | Diagnose Mitsubishi Mini Split P6 Error Code Fix: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| Mitsubishi P8 Error Code — Causes & Fix | What Mitsubishi mini-split P8 means, why the compressor faults, and how to diagnose and fix it. | Fix → |
| Mitsubishi PUY Air Handler Error Codes | Mitsubishi PUY guide for City Multi air-handler codes, remote communication, fan faults, drain sensors, EEV errors, and pipe sensors. | Fix → |
| Mitsubishi U1 Error Code — Causes & Fix | Mitsubishi U1 guide for voltage imbalance, phase loss, loose disconnect lugs, power sags, surge events, and inverter-board checks. | Fix → |
| Mitsubishi U2 Error Code — Causes & Fix | Diagnose Mitsubishi U2 Error Code - Causes & Fix: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| Mitsubishi U3 Error Code — Causes & Fix | Mitsubishi U3 guide for closed service valves, low refrigerant charge, branch-box leaks, solenoid valves, low ambient, and equalization checks. | Fix → |
| Mitsubishi U6 Error Code — Causes & Fix | Diagnose Mitsubishi U6 Error Code - Causes & Fix: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| Mitsubishi U7 Error Code — Refrigerant System Fault | Mitsubishi mini-split Error Code U7 means an outdoor unit fan motor or inverter fault. Learn the causes, how to diagnose, and how to fix Mitsubishi U7. | Fix → |
Fujitsu Error Codes (7 guides)
| Guide | Description | Fix |
|---|---|---|
| Fujitsu 00:A1 Heat Pump Error Code | Fujitsu 00:A1 guide for heat pump and mini-split faults, reset checks, indoor PCB issues, power faults, and compressor protection. | Fix → |
| Fujitsu Mini Split E1 Error Code — Causes & Fix | Troubleshoot Fujitsu E1 on HVAC equipment with checks for power, airflow, sensors, ignition, safety circuits, and parts to price before service. | Fix → |
| Fujitsu Mini Split E3 Error Code — Causes & Fix | Fujitsu mini-split E3 guide for communication faults, indoor/outdoor wiring, terminal checks, control boards, sensors, and service decisions. | Fix → |
| Fujitsu Mini-Split E7 Error Code — Causes & Fix | Diagnose Fujitsu Mini-Split E7 Error Code - Causes & Fix: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| Fujitsu Mini Split Diagnostic Error Codes — 2-Digit Code Guide | Fujitsu mini split 2-digit diagnostic error codes: 01, 04, 05, 07, 11 and more. How to enter diagnostic mode, read codes, and fix each fault. | Fix → |
| Fujitsu Mini-Split Error Code E9 — Refrigerant Circuit Fault | Fujitsu mini-split E9 guide for refrigerant-circuit faults, EEV coil checks, loose connectors, PCB driver issues, and pro-service decisions. | Fix → |
| Fujitsu Mini Split Leaking Water - Drain and Pump Checks | Fujitsu mini split leaking water guide for clogged drains, dirty filters, iced coils, float switches, condensate pumps, and safe repair decisions. | Fix → |
Amana Error Codes (4 guides)
| Guide | Description | Fix |
|---|---|---|
| Amana ASX Air Conditioner Error Codes | Amana ASX guide for LED flash codes, pressure-switch faults, compressor overload, control-board faults, thermistors, and low-voltage checks. | Fix → |
| Amana Furnace 3 Flash Error Code - Pressure Switch Fault | Troubleshoot Amana 3 flashes on HVAC equipment with checks for pressure switches, venting, condensate, wiring, and parts to price before service. | Fix → |
| Amana Furnace Error Codes - Ignition, Pressure, Flame, and Limit Faults | Amana furnace codes identify ignition, pressure switch, flame sensor, limit, rollout, polarity, and control-board faults. | Fix → |
| Goodman Furnace Error Codes 1-8 | Goodman furnace 1-8 flash-code guide for pressure switch, rollout, limit, ignition, flame-sense, gas-valve, and control-board faults. | Fix → |
American-standard Error Codes (3 guides)
| Guide | Description | Fix |
|---|---|---|
| American Standard AccuLink Error Codes | American Standard AccuLink guide for communicating thermostat faults, alert codes, sensor issues, outdoor-unit errors, and repair decisions. | Fix → |
| American Standard Furnace 3 Flash - Pressure Switch Fault | What 3 flashes on an American Standard furnace means, why the pressure switch faults, and how to diagnose and fix it. | Fix → |
| Trane Furnace 2 Flashes Pressure Switch Code | Trane furnace 2-flash guide for stuck-closed pressure switches, manometer testing, inducer checks, condensate problems, and code 3 differences. | Fix → |
General HVAC Guides (246 guides)
| Guide | Description | Fix |
|---|---|---|
| ABB ACH580 HVAC VFD Fault Codes | ABB ACH580 fault-code guide for HVAC drives, covering power, motor, temperature, fieldbus, configuration, reset, and replacement-part decisions. | Fix → |
| ABB ACS880 Fault 2310 - Overcurrent Diagnosis and Fix | ABB ACS880 2310 troubleshooting for current spikes, drive fault snapshots, motor/cable isolation, ramp tuning, and when the drive is suspect. | Fix → |
| AC Compressor Replacement Cost vs New Unit | AC compressor replacement cost guide for repair pricing, full-system replacement, refrigerant type, labor, warranty age, and quote decisions. | Fix → |
| AC Compressor Replacement Cost | Compare AC compressor repair cost against system replacement. See price ranges, age cutoffs, refrigerant issues, warranty, and replacement timing. | Fix → |
| AC Not Cooling Enough - Weak Cooling and Airflow Checks | AC cooling guide for weak airflow, frozen coils, dirty condensers, low refrigerant, fan faults, TXV issues, and when service is needed. | Fix → |
| Air Conditioner Not Cooling Error Codes Guide | Air-conditioner not-cooling code guide for pressure trips, frozen coils, capacitor faults, airflow issues, refrigerant leaks, and sensor faults. | Fix → |
| AC Refrigerant Leak Symptoms and Repair Costs | AC refrigerant leak guide for ice on lines, hissing, warm air, leak detection, repair costs, R22 phaseout, and when EPA-certified service is required. | Fix → |
| AirEase Furnace E1 Error Code - Ignition Lockout | AirEase furnace E1 means ignition lockout. Check the igniter, flame sensor, pressure switch hose, venting, condensate drain, and gas supply. | Fix → |
| Allen-Bradley PowerFlex 525 F003 Fault | PowerFlex 525 F003 guide for input phase-loss trips, unstable line power, blown fuses, wiring faults, false trips, and replacement-drive decisions. | Fix → |
| Amana AVXC18 Heat Pump Error Codes | Amana AVXC18 fault-code guide for communicating heat pumps, covering control-board, inverter, reversing-valve, refrigerant, and sensor faults. | Fix → |
| American Standard Gold 824 Thermostat Errors | American Standard Gold 824 error-code guide for AccuLink communication faults, thermostat alerts, sensor errors, and HVAC equipment checks. | Fix → |
| American Standard Platinum 18 Heat Pump Error Codes | AccuLink fault-code guide for Platinum 18 heat pumps, covering thermostat, outdoor unit, inverter, air-handler, sensor, and communication faults. | Fix → |
| A.O. Smith Signature 900 Error Codes | A.O. Smith Signature 900 tankless error-code guide for ignition, flow, overheating, sensors, descaling, venting, and water-heater part checks. | Fix → |
| AO Smith Water Heater 4 Flashes | AO Smith 4-flash water-heater guide for igniter faults, flame sensing, gas supply, wiring checks, reset limits, and service decisions. | Fix → |
| AO Smith Water Heater 3 Flashes | AO Smith 3-flash guide for pilot outage, thermocouple and thermopile faults, gas-valve lockout, burner cleaning, and relight checks. | Fix → |
| Aprilaire 68 Dehumidifier Fault Codes | Aprilaire 68 dehumidifier guide for E1 freeze protection, high-pressure trips, compressor faults, drain alarms, airflow, and sensors. | Fix → |
| Aprilaire 700 Humidifier Error Codes - Solenoid, Water Panel, Fan, and Drain | Aprilaire 700 humidifier guide for LED states, no-humidity calls, solenoid valves, water panels, fan faults, drains, and control checks. | Fix → |
| Aprilaire Dehumidifier Error Codes | Aprilaire dehumidifier code guide for E1-E9 faults, humidity sensors, airflow, defrost, drains, float switches, fan motors, and pro repair limits. | Fix → |
| Armstrong Air Handler E1 Error Code - Communication Fault Fix | Armstrong air handler E1 means communication fault. Check iComfort wiring, terminal blocks, thermostat, outdoor board, and bus power. | Fix → |
| Armstrong Furnace E4 Error Code - Ignition Lockout | Armstrong furnace E4 means ignition lockout. Check the ignitor, flame sensor, gas valve, inducer, pressure switch, and gas supply. | Fix → |
| Armstrong Pump Fault Codes - VFD, Sensor, Flow, and Dry-Run Trips | Armstrong Design Envelope pump faults cover motor current, drive temperature, voltage, BAS communication, sensor, flow, and dry-run trips. | Fix → |
| Baltimore Aircoil Cooling Tower Fault Codes | Baltimore Aircoil guide for VXT, VTL, and Series V tower alarms, including fan overload, water level, basin temperature, and VFD trips. | Fix → |
| Best Manometer for HVAC Gas Pressure Checks | HVAC manometer buying guide for gas pressure, inducer draft, static pressure, pressure switches, tubing, adapters, and safe field use. | Fix → |
| Best Multimeter for HVAC Troubleshooting | HVAC multimeter buying guide for voltage, continuity, microamps, capacitance, temperature, clamp amps, safety rating, and field use. | Fix → |
| Best Thermal Imager for HVAC - Resolution and Leak Checks | HVAC thermal imager buying guide for resolution, sensitivity, overlay, temperature range, reports, and cooling or heating diagnostics. | Fix → |
| Beverage-Air MT27 Error Codes | Beverage-Air MT27 refrigeration guide for controller faults, sensor errors, defrost issues, temperature alarms, diagnosis steps, and replacement parts. | Fix → |
| Boiler vs. Furnace Replacement Cost Guide | Boiler vs furnace replacement guide comparing hydronic and forced-air heat, installed costs, conversion work, efficiency, comfort, and maintenance. | Fix → |
| Bosch Heat Pump E1 Error Code - Communication Fault | Bosch heat pump E1 points to communication or sensor trouble. Check low-voltage wiring, indoor-outdoor communication, sensors, and board power. | Fix → |
| Bosch Heat Pump Error Codes | Bosch heat-pump error-code guide for IDS 2.0, BOVA, and Climate 5000 systems. Check sensors, airflow, refrigerant pressure, and boards. | Fix → |
| Bosch IDS 2.0 Heat Pump Error Codes | Bosch IDS 2.0 fault-code guide for active E-codes, stored F-codes, communication faults, sensors, inverter trips, airflow, and refrigerant issues. | Fix → |
| Bosch IDS Heat Pump Error Codes - Original Series Fault Guide | Complete fault code guide for the Bosch IDS original series heat pump. Covers all error codes, diagnostic steps, and differences from the IDS 2.0 series. | Fix → |
| Bradford White Infiniti K Tankless Water Heater Error Codes | Bradford White Infiniti K tankless codes flag ignition, flame loss, combustion, condensate, scale, thermal fuse, and sensor faults. | Fix → |
| Bryant Evolution Communication Fault | Bryant Evolution communication-fault guide for Connex bus wiring, thermostat errors, lost equipment signals, board checks, and repair decisions. | Fix → |
| Bryant Furnace 13 Error Code - Limit Device Open | Bryant furnace 13 means a limit device opened. Check the filter, blower, rollout switch, ducts, capacitor, and heat-exchanger safety. | Fix → |
| Bryant Furnace 31 Error Code - Pressure Switch Open | Bryant furnace 31 means the pressure switch did not close. Check condensate, vent pipes, pressure hoses, inducer speed, and switch rating. | Fix → |
| Bryant Furnace 33 Error Code - Limit Device Lockout | Bryant furnace 33 means a limit device opened during heat. Check the filter, blower, coil, rollout switches, ducts, and limit rating. | Fix → |
| Burnham Boiler B26, Err 4, and Err 6 Codes | Burnham B26, Err 4, and Err 6 guide for safety-limit and flame-sensing faults on Alpine, Series 2, MPO, Pinnacle, ES2, and SCG boilers. | Fix → |
| Burnham Boiler E1 Lockout Code Fix | Burnham E1 lockout guide for failed ignition, gas supply checks, igniter and flame-sensor tests, control-board limits, and safe reset decisions. | Fix → |
| Burnham Boiler E4 Error Code — Flame Loss During Operation | Burnham boiler E4 means flame loss during operation. Check gas pressure, flame sensing, vent draft, condensate blockage, and burner condition. | Fix → |
| Burnham Series 2 Boiler Error Codes - Lockout, Limit, Ignition, and Flame Faults | Burnham Series 2 boiler faults cover ignition lockout, flame proving, rollout, high-limit trips, pressure switches, and circulator problems. | Fix → |
| Carrier 24ACC6 Heat Pump Error Codes | Carrier 24ACC6 heat-pump flash-code guide for pressure trips, defrost sensors, discharge temperature, low voltage, fan faults, and repair decisions. | Fix → |
| Carrier Infinity 24VNA6 Heat Pump Error Codes | Carrier 24VNA6 Greenspeed guide for Infinity faults 168, 178, 179, inverter trips, control-board errors, refrigerant faults, and sensor checks. | Fix → |
| Carrier Comfort 24ACC4 Flash Codes | Carrier 24ACC4 flash codes help diagnose capacitor, compressor, fan motor, pressure-switch, and control-board faults on Comfort air conditioners. | Fix → |
| Carrier Infinity Touch Thermostat Error Codes | Carrier Infinity Touch guide for alert codes, indoor and outdoor faults, communication errors, pressure switches, sensors, and technician decisions. | Fix → |
| Champion TH16 Fault Code 4 - Heat Pump Lockout Diagnosis | Champion TH16 heat pump fault code 4 diagnosis. What the board is telling you, what to check first, and when the fault needs a licensed HVAC technician. | Fix → |
| Chigo Mini Split E1 Error Code — Communication Error Fix | Chigo Mini Split E1 Error Code - Communication Error Fix: likely causes, checks, and repair decisions before replacing parts. | Fix → |
| ClimateMaster Geothermal Error Code E1 — High Pressure Fault | ClimateMaster geothermal heat pump Error Code E1 means a high-pressure lockout. Learn the exact causes, diagnostics, and fixes for this geothermal fault. | Fix → |
| ClimateMaster Trilogy Geothermal Error Codes: Complete Guide | ClimateMaster Trilogy geothermal heat pump error codes. Trilogy Q fault codes, causes, and technician-level troubleshooting procedures. | Fix → |
| Coleman-Evcon Furnace Error Codes | Coleman-Evcon furnace guide for LED flash codes, pressure switches, ignition faults, rollout trips, limit switches, flame sensing, and blower issues. | Fix → |
| Coleman Furnace 4 Flashes High-Limit Fault | Coleman furnace 4 flashes means the high-limit switch opened. Check airflow, filters, blower speed, return ducts, gas input, and limit switch wiring. | Fix → |
| Coleman Furnace E2 Error Code — Causes & Fix | What Coleman furnace E2 means, why the pressure switch faults, and how to diagnose and fix it. | Fix → |
| Comfortmaker Furnace E1 Error Code - Lockout and Safety Checks | Comfortmaker E1 means furnace lockout after ignition, pressure-switch, limit, or rollout faults. Check flame sensing, airflow, venting, and switches. | Fix → |
| Comfortmaker Furnace E4 Error Code - Ignition Failure Lockout | Comfortmaker E4 means ignition failure lockout. Watch the igniter, clean the flame sensor, verify gas-valve voltage, and check gas pressure safely. | Fix → |
| Cooper & Hunter Mini Split E3 Error Code — Causes & Fix | What Cooper & Hunter mini split error code E3 means, why low pressure protection trips, and how to diagnose and fix it. | Fix → |
| Copeland Compressor Error Code 1 High Pressure Cutout | Copeland error code 1 guide for high-pressure cutout trips on scroll compressors, including condenser airflow, fan, overcharge, and switch checks. | Fix → |
| Crown Boiler E1 Error Code — Lockout Guide | Crown Boiler E1 error means an ignition lockout. This guide covers Crown Bimini, Aruba, and Sentinel boiler E1 diagnosis, reset, and common causes. | Fix → |
| Daikin Applied Chiller Fault Codes Guide — WMC / AGZ / ALZ Series | Daikin Applied chiller fault codes for WMC, AGZ, ALZ, and centrifugal chillers: alarm descriptions, causes, and troubleshooting steps. | Fix → |
| Daikin Aurora Heat Pump Error Codes | Daikin Aurora guide for A1, A3, A6, C4, E3, E7, F3, H6, U2, and U4 faults on cold-climate inverter heat pumps. | Fix → |
| Daikin VRV IV Fault Codes | Daikin VRV IV guide for zone-controller faults, refrigerant circuit errors, sensor codes, inverter trips, configuration issues, and service-tool checks. | Fix → |
| Danfoss FC102 VLT HVAC Drive Fault Codes | Danfoss FC102 fault-code guide for AL 2, AL 14, AL 17, AL 29, BACnet/Modbus faults, LCP resets, cooling fans, thermistors, and drive checks. | Fix → |
| Ducane Furnace E1 Error Code — Causes & Fix | Diagnose Ducane Furnace E1 Error Code - Causes & Fix: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| Eccotemp FVI12 Tankless Error Codes | Eccotemp FVI12 indoor tankless guide for E1-E9 faults, including ignition, airflow, venting, access, temperature, flow, and fan diagnostics. | Fix → |
| Eccotemp i12 Tankless Error Codes | Eccotemp i12 indoor tankless guide for E1-E9 faults, including ignition failure, flame loss, temperature sensors, water flow, and fan issues. | Fix → |
| ECM Blower Motor Error Codes Guide — Genteq / Regal Beloit | ECM blower motor code guide for Genteq, Regal Beloit, and OEM modules: low airflow, control input, overtemperature, DC bus, and no-power faults. | Fix → |
| ecobee SmartThermostat Premium Error Codes - Full Fault Reference | ecobee SmartThermostat Premium Error Codes - Full Fault Reference: likely causes, checks, and repair decisions before replacing parts. | Fix → |
| ecobee Thermostat E1 Error — Heating System Fault | Diagnose ecobee Thermostat E1 Error - Heating System Fault: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| EcoSmart ECO 18 Tankless Error Codes | EcoSmart ECO 18 guide for electric tankless faults, including heating-element, flow-sensor, temperature-sensor, wiring, and reset diagnostics. | Fix → |
| EcoSmart ECO 36 Error Codes | EcoSmart ECO 36 electric tankless guide for flow, amperage, heating-element, temperature-sensor, and control-board error codes. | Fix → |
| EcoSmart ECO 27 Error Codes | EcoSmart ECO 27 electric tankless guide for E1-E4 and Err faults covering flow sensors, heating elements, thermistors, and thermal cutoffs. | Fix → |
| Emerson White-Rodgers Thermostat E1 Error | Emerson and White-Rodgers E1 guide for 1F80, 1F86, 1F95, and UP500W thermostat sensor faults, power issues, and wiring checks. | Fix → |
| Understanding Industrial Error Codes — Master Guide | How to read and understand industrial error codes for HVAC, VFDs, CNC machines, and commercial equipment. | Fix → |
| EVAPCO Cooling Tower Fault Codes Guide — AT / LSTE Series | EVAPCO cooling tower fault codes and alarm conditions for AT, LSTE, and closed-circuit evaporative coolers: causes, diagnostics, and troubleshooting steps. | Fix → |
| Florida Heat Pump Error Codes Guide | Florida Heat Pump fault-code guide for FHP geothermal units, water-loop trips, freeze protection, low pressure, high pressure, sensors, and resets. | Fix → |
| Friedrich Mini-Split Error Codes | Friedrich mini-split guide for E-codes and F-codes covering sensors, fan faults, pressure protection, communication errors, and drain issues. | Fix → |
| Frigidaire Mini Split E1 Error Code — Communication Error Fix | Frigidaire Mini Split E1 Error Code - Communication Error Fix: likely causes, checks, and repair decisions before replacing parts. | Fix → |
| Furnace Age Guide: When to Repair and When to Replace | Furnace age guide for serial numbers, efficiency, repair-versus-replace timing, heat-pump comparisons, and tax-credit planning. | Fix → |
| Furnace Blowing Cold Air - 8 Causes and How to Fix Each | A furnace blowing cold air usually means fan-only mode, ignition failure, dirty flame sensor, limit cycling, bad capacitor, or clogged airflow. | Fix → |
| Furnace Error Code Lookup Tool: All Brands | Master furnace error code lookup guide covering Carrier, Goodman, Lennox, Trane, York, Rheem, Bryant, Heil, Amana, Coleman, and more. | Fix → |
| Furnace Filter Size and MERV Guide | Find the right furnace filter size by reading the label, measuring the slot, checking return grilles, comparing MERV ratings, and matching airflow. | Fix → |
| Furnace Flashing Red Light: What It Means and How to Fix It | Furnace red-light flash guide for pressure-switch, limit-switch, ignition, flame-sensor, rollout, polarity, and control-board patterns. | Fix → |
| Furnace High Limit Switch Keeps Tripping | Find why a furnace high limit switch keeps tripping. Check airflow, filter restriction, blower speed, temperature rise, and switch ratings. | Fix → |
| Furnace Hot Surface Igniter Replacement | Test, size, and replace a furnace hot surface igniter safely. Compare silicon nitride vs carbide igniters, resistance checks, and wiring fit. | Fix → |
| Furnace Repair or Replace Cost Guide | Furnace repair-vs-replace guide for age, repair cost, heat exchanger risk, safety red flags, efficiency, and installed replacement cost. | Fix → |
| Furnace Rollout Switch Tripped | A tripped furnace rollout switch signals flame rollout risk. Check burners, heat exchanger damage, venting, manual reset limits, and safety shutoff causes. | Fix → |
| Furnace Repair vs. Replace Age Guide | Furnace age guide for the 15-year rule, repair thresholds, heat exchanger risk, efficiency losses, and when replacement beats repair. | Fix → |
| Furnace Short Cycling - Causes, Fixes, and Parts to Replace | Troubleshoot Furnace Short Cycling - Causes, Fixes, and Parts to Replace: likely causes, field checks, and repair decisions before replacing parts. | Fix → |
| Furnace Won't Ignite - 7 Causes and How to Fix Each | A furnace that will not ignite often traces to a cracked igniter, dirty flame sensor, pressure switch fault, gas valve issue, or blocked drain. | Fix → |
| Gas Furnace Won't Turn On: Troubleshooting Guide | Diagnose a gas furnace that won't turn on. Check thermostat, filter, igniter, gas supply, limit switch, pressure switch, and common no-heat failures. | Fix → |
| Gas Leak from HVAC System: What to Do | HVAC gas-leak safety guide for gas odors near furnaces or vents, shutoff steps, evacuation decisions, utility calls, and technician repairs. | Fix → |
| Gibson Furnace E1 Error Code — Causes & Fix | Diagnose Gibson Furnace E1 Error Code - Causes & Fix: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| Goodman GVZC18 Heat Pump Error Codes | Goodman GVZC18 guide for iQ Drive inverter, communicating thermostat, outdoor board, sensor, motor, and variable-speed faults. | Fix → |
| Goodman Heat Pump Flash Code Guide | Goodman heat pump flash-code guide for GSZ, DSZC, and GSXC units, with pressure switch, defrost, outdoor-board, and airflow faults. | Fix → |
| Gree Mini Split E1 Error Code — Causes & Fix | What Gree mini split error code E1 means, why high pressure protection trips, and how to diagnose and fix it. | Fix → |
| Gree Mini Split E3 Error Code — Causes & Fix | What Gree mini split error code E3 means, why low pressure protection trips, and how to diagnose and fix it. | Fix → |
| Gree Mini-Split E6 Error Code — Causes & Fix | Diagnose Gree Mini-Split E6 Error Code - Causes & Fix: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| Cracked Heat Exchanger Symptoms and Replacement | Cracked heat-exchanger guide for CO risk, flame rollout, soot, rust, inspection limits, second-opinion checks, and furnace replacement decisions. | Fix → |
| Heat Pump Auxiliary Heat Always On - Causes and Fixes | Aux heat that runs constantly can point to high balance-point settings, outdoor sensor error, low refrigerant, defrost trouble, or heat-pump failure. | Fix → |
| Heat Pump Defrost Mode - What It Is and When to Worry | Heat-pump defrost guide covering steam from the outdoor unit, normal winter cycles, stuck defrost symptoms, auxiliary heat behavior, and failed parts. | Fix → |
| Heat Pump Error Codes: All Brands Guide | Heat-pump error-code guide for high pressure, low pressure, defrost, communication, sensor, compressor, and inverter protection faults. | Fix → |
| Heat Pump Freezing Up - Causes, Fixes, and When to Call a Tech | Your heat pump is freezing up. Here is why ice forms on the outdoor unit, how to fix the common causes, and when you need a technician. | Fix → |
| Heat Pump Repair vs. Replace Cost Guide | Heat pump repair-vs-replace guide using system age, repair cost, efficiency, refrigerant type, compressor risk, and warranty status. | Fix → |
| Heat Pump Not Heating - Why It Happens and How to Fix It | Your heat pump is running but not heating your home. Here are the common causes including thermostat errors, reversing valve failure, and refrigerant issues. | Fix → |
| Heat Pump Short Cycling - Causes, Diagnosis, and Fix Guide | Troubleshoot Heat Pump Short Cycling - Causes, Diagnosis, and Fix Guide: likely causes, field checks, and repair decisions before replacing parts. | Fix → |
| Heat Pump vs Gas Furnace Cost Guide | Heat pump vs gas furnace cost guide for upfront price, utility rates, climate fit, rebates, lifespan, ductwork, and replacement decisions. | Fix → |
| Heil Furnace E1 Error Code — Causes & Fix | What Heil furnace E1 means, why the pressure switch faults, and how to diagnose and fix it. | Fix → |
| Heil Furnace E2 Error Code — Causes & Fix | Diagnose Heil Furnace E2 Error Code - Causes & Fix: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| Heil Furnace E4 Error Code — Causes & Fix | Diagnose Heil Furnace E4 Error Code - Causes & Fix: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| Heil Ion Heat Pump Error Codes | Heil Ion heat-pump guide for communicating thermostat faults, high-pressure trips, soft lockouts, hard lockouts, sensors, and outdoor controls. | Fix → |
| Honeywell HM512 Humidifier Error Codes — Complete Guide | Honeywell HM512 humidifier codes point to fill, drain, scale, sensor, steam hose, canister, and control-board faults. | Fix → |
| Honeywell T6 Pro Thermostat Error Codes | Honeywell T6 Pro guide for E1, E2, and E3 thermostat faults, including room sensors, outdoor sensors, battery power, and wiring checks. | Fix → |
| Honeywell Thermostat E1 Error Code — Sensor Fault Fix | Honeywell thermostat E1 means the internal sensor failed or drifted. Check moisture, wiring power, placement, firmware, then replace the thermostat. | Fix → |
| Honeywell Thermostat E2 Error: Battery or Power Loss | Honeywell thermostat E2 guide for weak batteries, corroded contacts, reset steps, C-wire power loss, 24VAC transformer checks, and fuse faults. | Fix → |
| Honeywell TrueZONE Zoning System Error Codes — Complete Guide | Honeywell TrueZONE error codes: all fault codes for HZ311, HZ322, HZ432, and other TrueZONE zone control panels with causes and fixes. | Fix → |
| Honeywell VisionPRO / T6 FC Fault — Fan Control Error | Honeywell FC fault code on VisionPRO and T6 thermostats means a fan control error. Here's what triggers it and how to restore normal operation. | Fix → |
| Honeywell T10 Pro/RTH9585 Thermostat Error Codes — Fix Guide | Honeywell T10 Pro and RTH9585 codes point to sensor, condensate, wiring, setup, and compressor-delay conditions on Wi-Fi thermostats. | Fix → |
| Hoshizaki KM-2000SAJ Error Codes | Hoshizaki KM-2000SAJ guide for E1-E6 faults, ice-thickness sensors, float switches, pressure trips, harvest errors, and control resets. | Fix → |
| Hoshizaki KM-901 Error Codes | Hoshizaki KM-901 fault codes E1 through E8 explained. Check harvest, thermistor, fan, pressure, water, and control-board problems. | Fix → |
| How to Replace an HVAC Dual Run Capacitor: Complete DIY Guide | Troubleshoot How to Replace an HVAC Dual Run Capacitor: Complete DIY Guide: likely causes, field checks, and repair decisions before replacing parts. | Fix → |
| How to Replace an HVAC Contactor Safely | Replace an HVAC contactor safely: symptoms to confirm, wiring checks, and part-selection notes before swapping the contactor. | Fix → |
| HVAC Error Code Troubleshooting: Beginner's Complete Guide | How to read HVAC error codes on furnaces, heat pumps, mini-splits, and boilers — a plain-language guide for homeowners and new technicians. | Fix → |
| How to Clean an HVAC Flame Sensor Safely | Clean an HVAC flame sensor safely: symptoms to confirm, flame-signal checks, and replacement cues before ordering parts. | Fix → |
| HVAC Pressure Switch Fault - Diagnosis and Fix Guide | HVAC pressure-switch fault guide for gas furnaces, inducer draft, blocked condensate drains, cracked hoses, stuck switches, and lockouts. | Fix → |
| R22 Refrigerant Phase-Out Costs | Compare R22 leak repair, reclaimed refrigerant, retrofit, and system replacement paths. See 2026 cost ranges, rebates, and R410A or R32 options. | Fix → |
| ICP Furnace E4 Error Code — Causes & Fix | Diagnose ICP Furnace E4 Error Code - Causes & Fix: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| Johnson Controls Penn Commercial Controls Faults | Johnson Controls Penn fault guide for A421, A350, P70, pressure controls, temperature controls, sensor alarms, and reset checks. | Fix → |
| Keeprite Furnace E1 Error Code — Causes & Fix | What Keeprite furnace E1 means, why the system locks out, and how to diagnose and fix it. | Fix → |
| Klimaire Mini Split E1 Error Code — Communication Error Fix | Klimaire Mini Split E1 Error Code - Communication Error Fix: likely causes, checks, and repair decisions before replacing parts. | Fix → |
| Lennox Merit 2024-2025 Furnace LED Codes | Lennox Merit 2024-2025 furnace LED guide for 1-9 flashes, ignition lockout, pressure switch faults, rollout trips, and service decisions. | Fix → |
| Lennox Merit Series Furnace Error Codes | Lennox Merit furnace LED guide for flash codes, pressure switch faults, ignition lockouts, flame signal, rollout trips, and reset limits. | Fix → |
| Lennox SL297NV Furnace Error Codes | Lennox SL297NV guide for iComfort faults, ignition lockout, pressure-switch errors, limit trips, ECM blower faults, and inducer checks. | Fix → |
| Lennox XP25 Heat Pump Error Codes | XP25 heat-pump guide for iComfort S30 alerts, inverter diagnostics, sensor faults, communication errors, control-board checks, and replacement parts. | Fix → |
| LG Mini Split CH01 Error Code — Causes & Fix | Troubleshoot LG CH01 on HVAC equipment with checks for power, airflow, sensors, condensate, safety circuits, and parts to price before service. | Fix → |
| LG Mini Split CH02 Error Code — Causes & Fix | Troubleshoot LG mini split CH02 on HVAC equipment with checks for coil sensors, wiring, control boards, and parts to price before service. | Fix → |
| LG Mini-Split CH05 Error Code — Causes & Fix | What LG mini-split CH05 means, why communication fails between indoor and outdoor units, and how to fix it. | Fix → |
| LG Mini Split CH10 Error Code — Causes & Fix | Troubleshoot LG CH10 on HVAC equipment with checks for fan speed, airflow, sensors, wiring, control boards, and parts to price before service. | Fix → |
| LG Mini-Split CH21 Error Code — Outdoor Unit High Pressure | LG mini-split CH21 error code means high pressure protection on the outdoor unit. Learn the causes, how to diagnose, and how to fix LG CH21. | Fix → |
| LG Mini-Split CH22 Indoor Fan Motor | LG mini-split CH22 guide for indoor fan motor lock, overcurrent, wiring checks, blower faults, PCB checks, and repair decisions. | Fix → |
| LG Mini-Split CH26 Error Code — CT Sensor Fault | LG mini-split CH26 error code means a current transformer (CT) sensor fault on the outdoor unit. Learn causes, diagnostic steps, and how to fix LG CH26. | Fix → |
| LG Mini-Split CH34 Error Code — Causes & Fix | Diagnose LG Mini-Split CH34 Error Code - Causes & Fix: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| LG Mini-Split CH38 Error Code — Causes & Fix | Diagnose LG Mini-Split CH38 Error Code - Causes & Fix: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| LG Mini-Split CH67 Error Code — Causes & Fix | Diagnose LG Mini-Split CH67 Error Code - Causes & Fix: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| LG Mini Split CH Error Codes | LG mini split error codes: every CH code with meaning, causes, and fixes for LG Art Cool, Dual Inverter, and multi-zone systems. | Fix → |
| LG Multi V VRF Error Codes - CH Indoor and Outdoor Faults | LG Multi V VRF CH-code guide for indoor and outdoor units: communication faults, inverter trips, sensors, refrigerant alarms, and technician checks. | Fix → |
| Lochinvar Boiler Error Code E03 — High Limit Tripped | Lochinvar E03 error means the high limit switch opened due to overtemperature. Learn why this happens on Knight and Crest boilers and how to fix it. | Fix → |
| Lochinvar Knight Boiler Error Messages — Complete Display Guide | Lochinvar Knight Boiler Error Messages - Complete Display Guide: likely causes, checks, and repair decisions before replacing parts. | Fix → |
| Luxaire Furnace E1 Error Code — System Lockout | Diagnose Luxaire Furnace E1 Error Code - System Lockout: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| Manitowoc Indigo NXT Error Code 8 | Manitowoc Indigo NXT error 8 guide for harvest-cycle faults, including hot-gas valve, harvest assist, water curtain, sensor, and board checks. | Fix → |
| Manitowoc NEO Ice Machine Error Codes | Manitowoc NEO fault codes for air-cooled and water-cooled cube ice machines. Diagnose fill, bin, harvest, sensor, and cleaning problems. | Fix → |
| Midea Mini Split E1 Error Code — Causes & Fix | What Midea mini split error code E1 means, why high pressure protection trips, and how to diagnose and fix it. | Fix → |
| Midea Mini Split Error Code E3 — Causes & Fix | Diagnose Midea Mini Split Error Code E3 - Causes & Fix: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| Midea Mini Split F1 Error Code — Causes & Fix | What Midea mini split error code F1 means, why the indoor ambient temperature sensor fails, and how to fix it. | Fix → |
| Midea U-Inverter Mini Split Error Codes | Midea U-Inverter guide for E1-E8 sensor, coil, communication, freeze-protection, fan, PFC, and compressor temperature faults. | Fix → |
| Midea Mini Split Error Codes — Complete Reference | Use this Midea Mini Split Error Codes - Complete Reference reference to match the code with likely causes, service checks, and repair decisions. | Fix → |
| Mini Split Blinking Lights: Error Code Guide | Mini-split blinking-light guide for operation, timer, defrost, E1 communication, F1/F2 thermistor, and P0 inverter fault patterns. | Fix → |
| Mini Split Codes Lookup by Brand | Mini split codes lookup for Daikin, Mitsubishi, Fujitsu, Gree, LG, Bosch, Carrier, and Cooper & Hunter communication, sensor, drain, and inverter faults. | Fix → |
| Mini-Split Ice Buildup on Indoor Unit - Causes and How to Fix It | Ice buildup on your mini-split indoor unit is a warning sign. Here are the causes including dirty filters, low refrigerant, and blocked drains. | Fix → |
| Mini-Split vs Central AC Cost Guide | Mini-split vs central AC guide for installed cost, SEER2 ratings, ductwork, zoning, rebates, comfort tradeoffs, and replacement decisions. | Fix → |
| Mitsubishi FR-A700 Fault Codes | Mitsubishi FR-A700 guide for E.OC, E.OV, E.THT, E.GF, E.ILF, E.IPF, E.FIN, brake, motor, fan, and option-card faults. | Fix → |
| Mitsubishi Mr. Slim P6 Error Code | Mitsubishi Mr. Slim P6 guide for outdoor inverter and compressor protection faults, reset checks, inverter-board testing, and service decisions. | Fix → |
| Mitsubishi MSY-GL Mini-Split Error Codes - Full Fault Guide | Complete Mitsubishi MSY-GL mini-split error code reference. All P-series flash codes, remote control codes, and diagnostic faults with DIY fix steps. | Fix → |
| Mr. Cool DIY Mini Split Error Codes — Complete Fault Code Guide | Mr. Cool DIY Mini Split Error Codes - Complete Fault Code Guide: likely causes, checks, and repair decisions before replacing parts. | Fix → |
| MrCool Universal Mini Split Error Codes | MrCool Universal guide for E1-E6 and P0 faults, including thermistors, float switches, communication wiring, IPM protection, and PCBs. | Fix → |
| Navien NCB-700 Boiler Error Codes | Navien NCB-700 guide for E001-E109 boiler faults, ignition, fan, sensor, flow, domestic hot water, heating loop, and repair decisions. | Fix → |
| Navien NFC Combi Boiler Error Codes: Complete Guide | Navien NFC combi boiler error codes and fault diagnostics. E-series error codes, causes, and technician-level troubleshooting procedures. | Fix → |
| Navien NPE-240S Error Codes | Navien NPE-240S guide for E001, E003, E004, E012, E016, E030, and E351 tankless faults involving ignition, flame loss, venting, and water flow. | Fix → |
| Nest Thermostat E1 No Power Fault | Nest thermostat E1 means no HVAC power detected. Check Rc/Rh wiring, C-wire power, blown fuses, float switches, low battery, and furnace board output. | Fix → |
| Nest Thermostat E73 Error — No Power to Rc Wire Fix | Nest thermostat E73 means it can't detect power on the Rc cooling wire. Check the furnace fuse first — a blown fuse causes most E73 errors. | Fix → |
| Nest Thermostat E74 Error — Low Battery Fault | Diagnose Nest Thermostat E74 Error - Low Battery Fault: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| Nest Thermostat W5 — What It Means (It's Usually Not an Error) | Nest thermostat W5 means 5th-stage heating is active, usually emergency heat. It's often not an error — here's when it's normal and when it isn't. | Fix → |
| Nordyne E1 Error Code — Causes & Fix | Troubleshoot Nordyne E1 on HVAC equipment with checks for power, airflow, sensors, ignition, safety circuits, and parts to price before service. | Fix → |
| Nordyne Furnace E4 Error Code — Causes & Fix | Diagnose Nordyne Furnace E4 Error Code - Causes & Fix: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| Noritz Error Code 90 — Causes & Fix | Diagnose Noritz Error Code 90 - Causes & Fix: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| Noritz NR111 Tankless Water Heater Error Codes: Complete Guide | Noritz NR111 tankless water heater error codes and fault diagnostics. Error codes, causes, and technician-level troubleshooting procedures. | Fix → |
| Panasonic Mini-Split H97 Error Code - Indoor/Outdoor Communication | Panasonic H97 means the indoor and outdoor units are not communicating. Check outdoor power, interconnect wiring, signal continuity, and board faults. | Fix → |
| Payne Furnace 13 Error Code — Causes & Fix | Diagnose Payne Furnace 13 Error Code - Causes & Fix: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| Payne Furnace 31 Error Code — Causes & Fix | Diagnose Payne Furnace 31 Error Code - Causes & Fix: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| Payne Furnace 33 Error Code — Causes & Fix | Diagnose Payne Furnace 33 Error Code - Causes & Fix: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| Peerless Pinnacle Boiler Error Code Guide | Peerless Pinnacle boiler error-code guide for lockouts, ignition faults, pressure trips, sensors, draft errors, condensate, and resets. | Fix → |
| Penn Commercial Controls Fault Codes | Penn pressure and temperature control faults point to high head pressure, low suction, failed sensors, manual-reset lockouts, or relay output trouble. | Fix → |
| Pioneer Mini Split E1 Error Code — Causes & Fix | What Pioneer mini split error code E1 means, why communication fails between indoor and outdoor units, and how to fix it. | Fix → |
| Pioneer Mini Split Error Code E6 — Causes & Fix | Diagnose Pioneer Mini Split Error Code E6 - Causes & Fix: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| Pioneer Mini Split Error Code F1 — Causes & Fix | Diagnose Pioneer Mini Split Error Code F1 - Causes & Fix: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| Pioneer Mini Split P0 Error Code — Causes & Fix | What Pioneer mini split error code P0 means, why high pressure protection trips, and how to diagnose and fix it. | Fix → |
| Pioneer WYS Series Mini Split Error Codes — Complete Fault Guide | Pioneer WYS Series Mini Split Error Codes - Complete Fault Guide: likely causes, checks, and repair decisions before replacing parts. | Fix → |
| PTAC Error Codes - Amana, GE Zoneline, LG, Friedrich | PTAC error-code guide for Amana, GE Zoneline, LG, Islandaire, and Friedrich units: diagnostic modes, thermistors, boards, filters, and resets. | Fix → |
| Signs of Refrigerant Leak in AC or Heat Pump | Refrigerant leak guide for iced coils, warm air, hissing, high bills, low charge symptoms, leak causes, EPA repair rules, and service decisions. | Fix → |
| RGF REME Halo LED Fault Codes — Complete Guide | RGF REME Halo LED fault codes: all indicator lights, error states, cell replacement guidance, and troubleshooting for the REME Halo LED air purifier. | Fix → |
| Rheem RA14 Heat Pump Error Codes | Rheem RA14 heat-pump flash-code guide for pressure trips, thermostat circuits, defrost faults, refrigerant warnings, and service decisions. | Fix → |
| Rheem Prestige RP20 Heat Pump Error Codes | Rheem RP20 guide for LED flash codes, EcoNet thermostat faults, pressure switches, sensors, reversing-valve issues, and refrigerant diagnostics. | Fix → |
| Rheem RTEX Electric Tankless Water Heater Error Codes | Rheem RTEX error-code guide for E1-E4 on RTEX-13, RTEX-18, RTEX-24, and RTEX-36 heaters. Check flow, elements, sensors, and wiring. | Fix → |
| Rheem RTGH-95DVLN Tankless Error Codes | Rheem RTGH-95DVLN guide for condensing tankless faults, secondary heat-exchanger issues, condensate problems, ignition failures, and sensor errors. | Fix → |
| Rinnai Error Code 11 No Ignition — Causes & Fix | Diagnose Rinnai Error Code 11 No Ignition - Causes & Fix: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| Rinnai I120CN Tankless Water Heater Error Codes: Complete Guide | Rinnai I120CN tankless water heater error codes and fault diagnostics. Error codes, causes, and technician-level troubleshooting procedures. | Fix → |
| Rinnai RU130iN Tankless Error Codes | Rinnai RU130iN guide for condensing tankless faults, including error 79 scale-sensor alerts, gas-pressure problems, ignition, venting, and fan codes. | Fix → |
| Ruud Achiever Plus Furnace Flash Codes | Ruud Achiever Plus guide for 1-9 LED flashes, ignition lockout, pressure-switch faults, rollout trips, limit trips, flame sense, and board faults. | Fix → |
| Ruud Furnace 4 Flashes — High Limit Switch Fault | Diagnose Ruud Furnace 4 Flashes - High Limit Switch Fault: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| Ruud Furnace 7 Flashes — Low Flame Signal | Diagnose Ruud Furnace 7 Flashes - Low Flame Signal: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| Ruud Prestige RP20 Heat Pump Error Codes | Ruud RP20 guide for LED flash codes, EcoNet communicating faults, pressure switches, sensors, reversing-valve issues, and refrigerant diagnostics. | Fix → |
| Ruud UGPH Furnace Error Codes | Ruud UGPH guide for 1-9 flash codes covering ignition lockout, pressure-switch faults, inducer problems, rollout trips, and limit faults. | Fix → |
| Ruud UPNL Heat Pump Error Codes | Ruud UPNL Prestige guide for communicating heat-pump faults, including pressure, sensor, fan, reversing-valve, control-board, and EcoNet errors. | Fix → |
| Samsung DVM S VRF Error Codes | Samsung DVM S guide for outdoor PCB 3-digit VRF faults, including E1xx communication, E2xx sensor, E3xx compressor, E4xx valve, and E5xx safety codes. | Fix → |
| Samsung DVM S VRF System Error Codes: Complete Guide | Samsung DVM S VRF system error codes and fault diagnostics. E-series and C-series fault codes for outdoor and indoor units, with technician fixes. | Fix → |
| Samsung Mini-Split E1-01 Error Code — Causes & Fix | What Samsung mini-split E1-01 means, why the outdoor temperature sensor faults, and how to fix it. | Fix → |
| Samsung Mini-Split E3-01 Error Code - Indoor Fan Motor Fault | Samsung mini-split E3-01 means the indoor fan motor stalled or lost feedback. Clean the blower wheel, check the motor connector, and test PCB output. | Fix → |
| Samsung Mini Split E4-01 Error Code — Causes & Fix | Troubleshoot Samsung E4-01 on HVAC equipment with checks for communication wiring, sensors, control boards, and parts to price before service. | Fix → |
| Samsung Mini-Split E5-01 Error Code — Outdoor Coil Sensor Fault | Samsung mini-split error code E5-01 means the outdoor coil temperature sensor is faulty. Learn causes, diagnostic steps, and how to fix Samsung E5-01. | Fix → |
| Samsung Mini Split Error Codes — Complete Fix Guide | Use this Samsung Mini Split Error Codes - Complete Fix Guide reference to match the code with likely causes, service checks, and repair decisions. | Fix → |
| Scotsman C0830 Ice Machine Error Codes | Scotsman C0830 guide for long-freeze, long-harvest, high-temperature, water, bin-control, curtain, sensor, and Prodigy LED faults. | Fix → |
| Emerson Sensi Thermostat Error Codes — Complete Guide | Emerson Sensi thermostat error codes explained: E1 through E9, Wi-Fi connection issues, and offline alerts. Fix common Sensi errors fast. | Fix → |
| Sensi Touch Thermostat Error Codes - Full Diagnostic Guide | Sensi Touch thermostat codes point to power, wiring, Wi-Fi, sensor, and HVAC equipment faults before replacing the thermostat. | Fix → |
| Senville Mini Split E1 Error Code — Causes & Fix | What Senville mini split error code E1 means, why indoor/outdoor communication fails, and how to restore the system. | Fix → |
| Senville Mini Split Error Code E5 — Causes & Fix | Diagnose Senville Mini Split Error Code E5 - Causes & Fix: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| Senville SENA Series Mini Split Error Codes — Complete Fault Guide | Senville SENA Series Mini Split Error Codes - Complete Fault Guide: likely causes, checks, and repair decisions before replacing parts. | Fix → |
| Takagi T-H3-DV Tankless Water Heater Error Codes | Takagi T-H3-DV guide for indoor condensing tankless faults, including ignition, flame loss, overheat, thermistor, fan, vent, and scale errors. | Fix → |
| Takagi TK-340X3-NIH Commercial Tankless Water Heater Error Codes | Takagi TK-340X3-NIH Commercial Tankless Water Heater Error Codes: likely causes, checks, and repair decisions before replacing parts. | Fix → |
| Takagi TK-Jr2 Tankless Error Codes | Takagi TK-Jr2 guide for codes 11, 12, 14, 16, 31, 52, 61, and 91 covering ignition, flame loss, sensors, fan faults, and exhaust issues. | Fix → |
| Tempstar Furnace E1 Error Code — Causes & Fix | Diagnose Tempstar Furnace E1 Error Code - Causes & Fix: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| Tempstar Furnace E4 Error Code — Causes & Fix | Diagnose Tempstar Furnace E4 Error Code - Causes & Fix: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| Tempstar Ion Heat Pump Error Codes - Fault Code Diagnostics | Tempstar Ion Heat Pump Error Codes - Fault Code Diagnostics: likely causes, checks, and repair decisions before replacing parts. | Fix → |
| Trane XL18i Heat Pump Error Codes | Trane XL18i guide for LED flash codes, ComfortLink II faults, pressure trips, defrost issues, fan problems, and sensor checks. | Fix → |
| Trane XR17 Heat Pump Error Codes | Trane XR17 guide for heat-pump fault codes, LED flash codes, ComfortLink II communication faults, refrigerant issues, and defrost problems. | Fix → |
| Trane XV15i Heat Pump Error Codes | Trane XV15i heat-pump fault guide for variable-speed errors, pressure trips, defrost issues, sensors, fan faults, and resets. | Fix → |
| Industrial Equipment Troubleshooting by Symptom | Industrial equipment problems by symptom — find the error code and fix for your specific situation. | Fix → |
| True GDM-23 Error Codes | True GDM-23 guide for digital sensor, defrost, and temperature-control faults, including E1-E6 checks and parts to inspect first. | Fix → |
| True GDM-49 Merchandiser Error Codes | True GDM-49 guide for E1-E6 controller faults, cabinet probes, evaporator fan failures, defrost problems, airflow checks, and parts. | Fix → |
| True GDM Error Codes | True GDM merchandiser guide for sensor, defrost, fan, and controller faults, with the field checks that protect product before the case warms up. | Fix → |
| True Refrigerator E1/P1 Probe Fault | True refrigerator E1 or P1 means the cabinet thermostat probe failed. Test sensor resistance, wiring, controller input, and GDM or T-Series fit. | Fix → |
| True T-49 Refrigerator Error Codes | True T-49 guide for E1-E6 refrigerator faults, cabinet sensors, evaporator sensors, defrost circuits, fan motors, and controller checks. | Fix → |
| HVAC UV Air Purifier Error Codes | HVAC UV air-purifier guide for Honeywell, Fresh-Aire UV, Sanuvox, Ultravation, lamp-life warnings, ballast faults, reset timers, and power checks. | Fix → |
| VRF vs. Multi-Zone Mini-Split | VRF vs. multi-zone mini-split guide comparing installed cost, building size, IEER efficiency, heat recovery, controls, and maintenance. | Fix → |
| Water Heater Not Getting Hot | Water-heater troubleshooting guide for lukewarm water, failed elements, thermostats, burners, gas controls, sediment, dip tubes, and service calls. | Fix → |
| WaterFurnace Geothermal Fault Code 1 — Low Pressure Lockout | WaterFurnace Fault Code 1 guide for low-pressure lockout, loop temperature, airflow, refrigerant leaks, TXVs, sensors, and safe reset checks. | Fix → |
| WaterFurnace Series 7 Geothermal Error Codes: Complete Guide | WaterFurnace Series 7 geothermal heat pump error codes and fault diagnostics. IntelliZone2 fault codes, causes, and technician-level fixes. | Fix → |
| WEG CFW11 VFD Fault Codes | WEG CFW11 fault-code guide for F-code trips and A-code warnings across power, current, temperature, feedback, and communication problems. | Fix → |
| Weil-McLain Boiler E13 Error — Low Water Pressure Fix & Diagnosis | Weil-McLain Boiler E13 Error - Low Water Pressure Fix & Diagnosis: likely causes, checks, and repair decisions before replacing parts. | Fix → |
| Weil-McLain Boiler Error Code E01 — Lockout Fix | Weil-McLain E01 boiler lockout guide for flame failure, ignition retries, flame sensors, igniters, gas valves, and burner controls. | Fix → |
| Weil-McLain E06 Error Code — Ignition Lockout | Diagnose Weil-McLain E06 Error Code - Ignition Lockout: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| Weil-McLain E05 Error Code - Sensor Fault | Weil-McLain E05 error means a temperature sensor fault on the boiler. Learn which sensor triggered E05, how to test it, and whether to repair or replace. | Fix → |
| Weil-McLain Ultra Series Boiler Error Codes: Complete Guide | Weil-McLain Ultra Series boiler error codes and fault diagnostics. E-series fault codes, causes, and technician-level troubleshooting procedures. | Fix → |
| Westinghouse Furnace E1 Error Code — Causes & Fix | Diagnose Westinghouse Furnace E1 Error Code - Causes & Fix: likely causes to check, measurements to verify, and repair decisions before parts replacement. | Fix → |
| Windmill AC Mini Split Error Codes — Complete Fault Code Guide | Windmill AC Mini Split Error Codes - Complete Fault Code Guide: likely causes, checks, and repair decisions before replacing parts. | Fix → |
| Yaskawa A1000 Fault Codes and Commissioning Guide | Yaskawa A1000 guide for drive faults, key parameters, commissioning, OC, OV, UV1, GF, motor overload, phase loss, and reset decisions. | Fix → |
| Yaskawa V1000 OV Fault - Overvoltage Trip Diagnosis | Yaskawa V1000 OV means DC bus overvoltage. Check decel ramps, regeneration, braking resistor sizing, input voltage, and overhauling loads. | Fix → |
| York Affinity Furnace Error Codes | York Affinity furnace guide for ignition, inducer, pressure-switch, limit, rollout, flame-sense, and control-board fault codes. | Fix → |
| York YXV Heat Pump Error Codes - Fault Code Reference | York YXV heat-pump fault guide for iQ Drive overcurrent, DC bus faults, pressure switches, sensors, defrost, and fan motor errors. | Fix → |
| York YZV Heat Pump Error Codes | York YZV fault-code guide for variable-speed heat pumps, covering control-board, communication, iQ Drive inverter, refrigerant, and sensor faults. | Fix → |
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