How do I fix LG LAN120HSV5 Ductless Mini Split Problems & Error Codes?

Follow the step-by-step diagnosis below. The most likely fix is identified by checking power, sensor resistance, and control-board signals in order — using a multimeter and the part numbers documented in the parts reference table.

Can I keep running the equipment with this fault active?

Generally no. Faults on Hvac units are emitted when a sensor, safety, or control circuit is outside its operating envelope. Running through an active fault risks compressor, heater, or control-board damage. Diagnose and clear the fault first.

What part is most commonly replaced for LG LAN120HSV5 Ductless Mini Split Problems & Error Codes?

The most frequently replaced parts for LG LAN120HSV5 Ductless Mini Split Problems & Error Codes are listed in the Parts Reference section of this guide with OEM part numbers and typical price ranges. Check the table for direct replacements.

Is LG LAN120HSV5 Ductless Mini Split Problems & Error Codes a DIY repair or do I need a technician?

Sensor swaps, fan motor replacements, and condenser cleaning are typical DIY-level repairs. Anything involving refrigerant, gas, or high-voltage (>240V) work requires a licensed technician for both safety and code-compliance reasons.

LG LAN120HSV5 Ductless Mini Split Problems & Error Codes

Q: What does LG LAN120HSV5 Ductless Mini Split Problems & Error Codes mean?

CH21 error code is the most common failure, caused by compressor overcurrent or inverter board faults requiring outdoor unit service.

LG LAN120HSV5 Ductless Mini Split Problems & Error Codes — Overview

The LG LAN120HSV5 is a ductless mini split air conditioner that relies on inverter-driven compressor technology for variable-speed cooling. The most frequent field problems center on the outdoor unit’s inverter control and compressor protection logic, particularly the CH21 fault code that indicates excessive current draw at the compressor or inverter. This error is treated by LG as a compressor lock or inverter overcurrent condition, not a simple sensor glitch, and requires outdoor unit inspection and testing. Other issues include refrigerant leaks, outdoor fan motor failures, and indoor unit airflow restrictions that reduce system capacity.

Jump to Common Problems

Most Common Problems on This Model

CH21 error code displayed on indoor unit Inverter PCB detects excessive compressor current due to a locked compressor, failed compressor winding insulation (below 10 MΩ), or a damaged inverter board with carbonization, requiring compressor or inverter PCB replacement after measuring phase-to-phase resistance balance and insulation to ground.
Unit runs but does not cool effectively Low refrigerant charge from a leak at flare connections or evaporator coil, or a clogged indoor air filter blocking airflow across the evaporator, requiring leak repair and recharge or filter cleaning.
Outdoor unit will not start or trips breaker Supply voltage outside the range of approximately 220 V ±10% for single-phase input, or a shorted inverter IPM module on the outdoor PCB, requiring voltage correction at the panel or inverter board replacement.
Intermittent operation or random shutdowns Loose or corroded connections at the outdoor unit main board, particularly the EEV harness or compressor terminal connectors, requiring inspection and re-seating or replacement of damaged harness terminals.
Outdoor fan runs but compressor does not start Compressor winding imbalance detected by inverter (unequal U-V, V-W, and U-W resistance readings), or a mechanically seized compressor, requiring compressor replacement.
Unit shows error after power cycle and will not clear Persistent CH21 or related inverter protection fault due to a failed inverter PCB component or compressor with internal short, requiring technician service to test DC link voltage (about 310 V DC on single-phase) and replace the defective part.
Reduced airflow from indoor unit Dirty evaporator coil or blower wheel in the indoor head restricting airflow, causing freeze-up or poor cooling, requiring coil cleaning and blower service.
Outdoor unit overheats or short-cycles Obstructed condenser coil or insufficient outdoor unit clearance blocking heat rejection, causing inverter to trip on overcurrent, requiring coil cleaning and verification of proper installation spacing per LG guidelines.

Parts That Commonly Fail

Part	Notes
Inverter PCB / IPM module	Amazon \| Outdoor board that drives the compressor; fails with carbonization, burn marks, or shorted IPM, triggering CH21.
Compressor	Amazon \| Inverter-driven scroll compressor; fails with winding imbalance, insulation breakdown below 10 MΩ, or mechanical lock.
Outdoor fan motor	Amazon \| Condenser fan motor in outdoor unit; fails due to bearing wear or winding damage, reducing heat rejection.
Electronic expansion valve (EEV) harness	Amazon \| Connector and wiring to EEV at outdoor unit; loose or damaged connections contribute to inverter faults.

When to Call a Pro

Call a licensed HVAC technician for any CH error code that does not clear after a full power cycle, for any compressor or inverter diagnostics requiring measurement of phase-to-phase resistance or insulation resistance, and for refrigerant leak repair or system recharge. Inverter PCB and compressor replacement both require refrigerant recovery, vacuum, and proper brazing, and the outdoor unit must be electrically isolated and tested with a megohmmeter and multimeter to identify the root cause of overcurrent faults. Supply voltage issues at the breaker panel and any work inside the outdoor unit electrical compartment should be handled by a qualified technician.