What does LG Mini Split Not Heating - Causes & Fix mean?

Most often caused by incorrect mode or setpoint. Verify heat mode is active and thermostat is set above room temperature.

How do I fix LG Mini Split Not Heating - Causes & Fix?

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 Mini Split Not Heating - Causes & Fix?

The most frequently replaced parts for LG Mini Split Not Heating - Causes & Fix 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 Mini Split Not Heating - Causes & Fix 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 Mini Split Not Heating - Causes & Fix

LG Mini Split Not Heating — What’s Happening

When an LG mini split is not heating, the unit fails to deliver warm air or hold the setpoint in heat mode. This is a performance symptom, not a single fault code. The cause may be as simple as a mode setting or as complex as a refrigerant leak, sensor fault, or compressor issue.

LG published guidance points to mode and setpoint checks first, then airflow obstructions, refrigerant or icing problems, and finally compressor, condenser, sensor, or control board failures. If an error code appears on the indoor display, that code maps to a specific fault such as communication error, overheat protection, or a sensor open or short.

Jump to Fix

Most Likely Causes

Incorrect mode or setpoint The unit is set to cool, fan, or auto instead of heat, or the setpoint is below room temperature.
Dirty or clogged air filter A blocked filter starves airflow across the indoor coil and reduces heating capacity.
Outdoor unit icing, snow, or debris blockage Ice, snow, or leaves around the outdoor coil or fan prevent proper heat exchange.
Low refrigerant from leak or improper charge Refrigerant loss causes weak heating and can freeze the indoor coil.
Frozen indoor coil Dirty filters, dirty coils, or low refrigerant can freeze the indoor coil and stop effective heating.
Faulty thermistor or sensor A failed indoor or outdoor temperature sensor sends incorrect readings to the control board.
Communication or PCB fault Loose wiring, broken connectors, or a failed indoor or outdoor control board prevent the unit from running heat mode.

How to Diagnose and Fix

Verify the remote or wall controller is set to heat mode and the setpoint is at least 5°F above current room temperature.
Power cycle the system at the breaker, wait two minutes, restore power, and recheck operation.
Remove and clean or replace the indoor air filter, then inspect the indoor coil for dust or ice.
Inspect the outdoor unit for ice, snow, or debris blocking the coil or fan, and clear any obstructions.
Check the indoor display or controller for any error code, and note the exact code if present.
Inspect communication wiring and connectors between indoor and outdoor units for loose, broken, or corroded connections.
Test indoor and outdoor thermistor resistance with a multimeter if airflow is clear and no code is shown but heating remains weak.
If refrigerant loss is suspected (weak heating, frozen coil, or hissing), call a licensed HVAC technician to locate leaks, recover refrigerant, repair the circuit, and recharge to specification.

Parts You Might Need

Part	Notes
LG mini split air filter	Amazon \| Washable or replaceable filter for the indoor unit.
LG indoor thermistor sensor	Amazon \| Temperature sensor mounted on the indoor coil or in the unit.
LG outdoor control board (PCB)	Amazon \| Inverter or main control board in the outdoor unit.

If your appliance also shows a code on the display, these match this problem:

When to Call a Pro

Call a licensed HVAC technician if you suspect refrigerant loss, if an error code persists after wiring and sensor checks, or if the compressor or inverter board appears faulty. Refrigerant work requires EPA certification and specialized gauges. Communication faults, PCB replacement, and compressor diagnosis involve live voltage checks and precise component isolation that are safest left to a professional. If the outdoor unit hums but the compressor does not start, or if you measure incorrect line voltage or DC link voltage on the inverter board, professional diagnosis and repair are recommended.