Posts

All the articles I've posted.

• Navien E021 Error Code - Causes & Fix

  30 May, 2026

  E021 means the cold water inlet thermistor has an open circuit. Most common fix: replace the failed sensor or repair its wiring.

• Navien E027 Error Code - Causes & Fix

  30 May, 2026

  E027 means abnormal air pressure sensor activity. Most often caused by blocked venting or a dirty air filter. Check airflow first.

• Navien E016 Error Code - Causes & Fix

  30 May, 2026

  E016 means heat exchanger overheat protection. Most common fix: clean the inlet filter and check for scale buildup in the exchanger.

• Navien Tankless E013 Error Code - Causes & Fix

  30 May, 2026

  E013 on Navien tankless means abnormal pump operation. Most common fix: check pump wiring and connectors, then replace the pump if faulty.

• Navien E011 Error Code - Causes & Fix

  30 May, 2026

  E011 on Navien tankless means high water pressure or a faulty pressure sensor. Most often fixed by replacing the water pressure sensor.

• Navien E010 Error Code - Causes & Fix

  30 May, 2026

  E010 signals abnormal air pressure or airflow fault in the combustion system. Clean the air filter and check vents for blockages first.

• Navien E008 Error Code - Causes & Fix

  30 May, 2026

  E008 means the outlet thermistor circuit is shorted. The most common fix is replacing the outlet temperature sensor or its wiring.

• Navien E007 Error Code - Causes & Fix

  30 May, 2026

  E007 means the hot water outlet thermistor circuit is open. Most likely fix: replace the outlet temperature sensor or repair its wiring.

• Navien E006 Error Code - Causes & Fix

  30 May, 2026

  E006 means the heating supply outlet thermistor is shorted. Most units need a new thermistor after checking wiring and connectors.

• Navien E005 Error Code - Causes & Fix

  30 May, 2026

  E005 means the flow sensor isn't spinning properly. Most likely fix: clear debris from the sensor or replace the flow sensor assembly.

• Navien E004 Error Code - Causes & Fix

  30 May, 2026

  E004 means false flame detection. Check for vent blockages and clean the flame rod first-most common fix for this safety lockout.

• Navien E002 Error Code - Causes & Fix

  30 May, 2026

  E002 means low water pressure or insufficient supply to your Navien tankless heater. Check that the inlet valve is fully open first.

• Lennox Furnace E275 Error Code - Causes & Fix

  30 May, 2026

  E275 means flame sensed out of sequence. The furnace detected flame when it shouldn't have, then lost it. Check for a leaking gas valve.

• Lennox E204 Error Code - Causes & Fix

  30 May, 2026

  E204 means blower motor communication fault. Most often fixed by repairing damaged wiring harness or replacing the blower motor.

• Navien E001 Error Code - Causes & Fix

  30 May, 2026

  E001 on Navien tankless heaters usually signals a flame detection or ignition fault. Clean the flame rod and check gas supply first.

• Lennox E290 Error Code - Causes & Fix

  30 May, 2026

  E290 means ignitor circuit fault on your Lennox furnace. The hot-surface ignitor has failed or its wiring is open. Replace the ignitor.

• Lennox E241 Error Code - Causes & Fix

  30 May, 2026

  E241 means flame sensed out of sequence. Clean the flame sensor first-it's the most common fix for this Lennox fault code.

• Lennox E270 Error Code - Causes & Fix

  30 May, 2026

  E270 means gas valve lockout after repeated failed ignitions. Usually a bad igniter or flame sensor. Reset only after finding cause.

• Lennox E206 Error Code - Causes & Fix

  30 May, 2026

  E206 means gas valve second-stage relay failure. Furnace runs on 1st stage only. Fix: check wiring, then replace control board.

• Lennox E205 Error Code - Causes & Fix

  30 May, 2026

  E205 means gas valve control relay contact shorted. Check wiring at the control board and gas valve, then replace the control if wiring is OK.

• Lennox E117 Error Code - Causes & Fix

  30 May, 2026

  E117 means poor ground detected on your Lennox furnace. Check equipment ground and 120V at the control to find the wiring fault.

• Lennox E125 Error Code - Causes & Fix

  30 May, 2026

  E125 means the integrated control board failed its self-check due to internal hardware fault. Most cases need board replacement.

• Bradford White 3 Flashes - Causes & Fix

  30 May, 2026

  3 flashes on a Bradford White gas water heater means a thermal well sensor or gas control fault. Most often the thermal well is damaged.

• Bradford White 5 Flashes Error Code - Causes & Fix

  30 May, 2026

  5 flashes on Bradford White gas water heaters means false pilot flame present. The pilot valve is stuck open and you need a new gas control.