LG Therma V fault CH53

What it means

Communication between Main PCB (Indoor) and Main PCB (Outdoor cycle) is lost/bad for less than 3 minutes. CH53 indicates the check sequence should start from the indoor unit side.

Likely causes

1. Abnormal input voltage (overvoltage/undervoltage)
2. Incorrect wiring
3. Poor power cable connection
4. Noise filter fault
5. Poor GND connection
6. Harness wiring connected to PCB not normal (open/short)
7. Ambient noise interference from nearby products or wires
8. Visible defects on Indoor PCB (noise filter, capacitor, etc.)
9. Communication line short circuit or burnout between Main PCB (Outdoor Cycle) and Main PCB (Indoor)
10. Main PCB (Outdoor Cycle) or Main PCB (Indoor) not powered
11. PCB burnout
12. Remote control terminal block not properly connected
13. Intermediate connection formed by twisting inner wire strands without soldering
14. Communication line shorted or disconnected
15. Main PCB(Indoor) CN-REMO voltage not present (fault on Main PCB)
16. Noise near wired remote control or communication line
17. Fan locked
18. Obstruction/shield around the heat exchanger
19. Insufficient distance between product and wall
20. Piping condition issues such as pipe bending
21. EEV operation/connection status fault
22. Abnormal refrigerant pressure
23. Compressor restraint
24. Compressor wiring reverse phase loss
25. Short circuit or opening of internal connection line in compressor
26. Compressor winding resistance out of spec
27. Compressor insulation resistance failure
28. Inverter PCB assembly or connector connection fault
29. IGBTM failure

Where to start

1. Check if input power and GND connection is normal. If No: check abnormal voltage (overvoltage/undervoltage), check for incorrect wiring, check power cable connection, check Noise Filter LED, check GND connection status. Measure: check power of switchboard, reconnect or replace line.
2. If input power is normal, check if the wiring of the harness connected to the PCB is normal. If No: reconnect or replace wire.
3. If wiring is normal, check if there are any products or wires that can cause noise. If No/noise present: secure additional distance from noise generating products or wires.