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Error code reference

LG Heat Pump Error Code P5

System down due to frozen heat exchanger

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What the P5 error code actually means

The P5 code means the indoor coil inside your LG heat pump has gotten too cold and frozen up, so the system shut itself off to prevent damage. This usually happens because air is not flowing properly through the unit, often due to a dirty filter or something blocking the vents. You should turn off the unit, let any ice melt, clean the air filter, and check that nothing is blocking the airflow around the indoor unit.

Diagnostic procedure

The full P5 procedure

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MyPros+ · DiagnosticsStep 1 preview
1
First diagnostic step
Check indoor unit for obstacles and clean air filter; check indoor fan motor operation; check PCB fan motor output voltage.
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Most common causes of P5

Ranked by how often they cause this code
  1. 1Clogged or dirty air filter
  2. 2Blocked indoor unit airflow
  3. 3Indoor fan motor failure or reduced output
  4. 4Low refrigerant charge
  5. 5PCB control board fault

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Questions people ask about P5

What does P5 mean on a LG heat_pump?
P5 on an LG heat pump means the indoor heat exchanger temperature dropped to -4°C or below and stayed there for more than 40 seconds, triggering a protective system shutdown. The unit shuts down to prevent further ice accumulation and compressor damage. The fault is almost always related to restricted airflow, a failing indoor fan motor, or a refrigerant system problem.
Is it safe to keep running the heat pump when P5 is displayed?
No, you should not attempt to force the unit to keep running when P5 is active. The system has already shut itself down as a protective measure, and continuing to operate with a frozen coil can damage the compressor and other refrigerant-side components. Allow the unit to thaw fully before attempting a restart.
How much does it cost to repair a P5 error on an LG heat pump?
Repair costs vary widely depending on the cause. Cleaning or replacing an air filter costs very little, typically under $20 to $40 for replacement filters. An indoor fan motor replacement can range from $150 to $400 including labor. Refrigerant-related repairs, including leak detection, repair, and recharge, typically range from $200 to $600 or more depending on the severity and refrigerant type.
Can I fix the P5 error myself?
Some causes of P5 are straightforward DIY fixes, such as cleaning a clogged air filter or removing obstructions around the indoor unit. Turn the unit off, allow any ice on the coil to thaw completely, then clean the filter and clear the airflow path before restarting. If the error returns after those steps, the fan motor or refrigerant system likely needs professional diagnosis.
Will resetting the unit clear the P5 error?
A power reset may clear the P5 fault temporarily and allow the unit to restart, but if the underlying cause is not addressed, the error will return within the same operating cycle. Resetting without fixing the root cause, such as a dirty filter or failing fan motor, will not resolve the problem and can lead to repeated shutdowns.

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