LG mini split error codes and troubleshooting guide

If there is an issue on any LG mini split unit, a two-digit error code (for example CH35) may blink on the Indoor Unit’s LED, or the Outdoor Unit PCB LEDs.

This guide lists the meaning of various LG mini split error codes and suggested repairs.

Let’s dive in:

LG mini split error codes – meaning and suggested fixes

LG mini split error codes ch 05

Meaning

The CH05 error code points to a communication error in the indoor/outdoor unit.

Possible causes

1. The indoor unit is not receiving power.
2. There is a power connection error in the indoor/outdoor unit (or communication line is not installed).
3. Wiring errors could have occurred- wiring not done properly.
4. The communication circuit parts in indoor/outdoor unit have fried.
5. External noise- a communication error can also occur due to external noises

Basic Troubleshooting

• Check power supply voltage to the outdoor/indoor units ( 230V ±10% ) and fix as necessary.
• Correct the wiring or any loose connections.

LG mini split error code ch 07

Meaning

The indoor unit is in a different (cool/heat) operation mode from master indoor unit.

Possible fix

• Change the mode -set indoor units (all) to cooling or heating to clear.
• If not successful, try to turn off the mini split (at remote controller) then turn the unit back on.

LG mini split error code ch10

Meaning

Indoor unit fan may have locked up (due to failed fan motor operation). Indoor unit LEDs blinks once.

LG mini split error code ch 21

Meaning

DC peak error/IPM fault. If not, compressor DC voltage might be too high.

Potential causes

1. Compressor has malfunctioned (short circuit).
2. Compressor is down-to-earth.
3. Inverter PCB could be faulty.
4. IPM issue.

Possible fix

Test the inverter’s DC power circuit for over current- there is over current if it exceeds 14 Amps.

Check compressor windings –you want to test their resistance. Measure from U-V, V –W, and W-U (the values to be between 0.25 & 5 Ohms each).

Finally, check if compressor is down-to-earth- measure the resistance (from any compressor terminal) to earth point (pipework). The value should be exceeding 2 M Ohms.

Quick Note: The compressor may need replacing if these tests fail.

LG mini split error code 26

Meaning

The inverter compressor may be seized (because of trouble with its positioning system)

Suggested solution

Verify if the compressor is connected properly and then reset the unit.

You can now start up the unit once again and see if the compressor will start.

LG mini split error codes ch35

LG mini split error code ch35 Meaning

Low pressure sensor issue.

Possible causes

1. Overload operation (due to the outdoor fan being constrained, screened, or blocked).
2. Insufficient Refrigerant due to leakage.
3. Pressure sensor is badly connected.
4. The compressor sensor is faulty.
5. The PCBA is defective.

Suggested fixes

• Check for Refrigerant leakage.
• Check and clear any blockages on your unit.

LG mini split error code ch 38

Meaning

1. Electrical problem (e.g. unstable power supply)
2. Low refrigerant- perhaps because of a leakage.

Proposed remedy

• Reset power to your unit- simply unplug it (or shut the circuit breaker off) for 5 minutes or so then plug it back in.
• Check the refrigerant level and have it refilled depending on your findings.

LG mini split error code ch 67

Meaning

Outdoor BLDC fan lock error (Outdoor fan motor may be seized) or the rotation sensing circuit is faulty.

Probable fixes

• Check the motor for both mechanical and electrical failure.
• Replace PCB (if you found the fine).

Summary of common errors

Error code	Meaning
1	Return air thermistor on LG mini split indoor unit disconnected/shorted out.
2	Inlet pipe thermistor disconnected/shorted out (Indoor unit).
5	Communication failure between indoor unit to the outdoor unit.
6	Outlet pipe thermistor disconnected/shorted out(Indoor unit)..
9	EEPROM error.
10	Indoor unit fan locked up (-fan motor operation failed-).
12	Middle pipe thermistor (indoor unit) disconnected/shorted out.
21	DC peak error/IPM fault Or compressor DC voltage too high.
22	Current transformer2(CT2) error/ AC input current too high.
23	DC link voltage too low.
25	Voltage to your system too low/too high.
26	Inverter compressor seized up/not providing rotation.
27	Prospective short circuit(PSC) issue error  OR current to the inverter compressor between AC&DC converter circuit too high.
28	Inverter compressor D.C. voltage too high.
29	Inverter compressor amperage too high.
31	Current to current transformer(CT) thermistor too low.
32	Discharge pipe temperature (on inverter compressor) too high.
40	Current transformer(CT) thermistor disconnected/shorted out.
41	Discharge pipe thermistor (Inverter compressor) has disconnected/shorted out.
44	Inlet air thermistor (Outdoor unit) disconnected/shorted out.
45	Outdoor unit’s condenser coil middle thermistor disconnected/shorted out.
46	Outdoor unit’s suction line thermistor disconnected/shorted out.
48	Outdoor unit’s coil outlet (liquid-line) thermistor disconnected/ shorted out.
53	Communication failure from the outdoor to indoor unit.
60	Outdoor unit’s PCB E.E.P.R.O.M. check sum error.
61	Outdoor unit condenser’s coil temperature too high.
62	Outdoor unit’s inverter compressor’ PCB heat sink temperature_ too high.
63	Condenser coil’s pipe thermistor temperature too low.
65	Heat sink thermistor disconnected/shorted out.
67	Outdoor BLDC_fan motor lock error.

LG Mini Split reset procedure

If everything fails to solve the error codes, resetting the unit could be helpful.

Here is how to reset your LG mini split:

1. Turn off the LG split air conditioner.
2. Unplug the AC and allow it to sit unplugged for 10 seconds (minimum).
3. Plug your air con back in.
4. Restart it by pressing the power button.

That’s it!

 

Wrapping it up

You now know what to check if trouble has occurred in your LG mini split system.

Use the above ideas to try DIY repairs before calling your local HVAC company- it could save you time and money!

More resources: Visit www.lg-dfs.com for more resources on troubleshooting LG mini split indoor error codes / LG mini split outdoor unit error codes. You can also reach out to LG DFS tech support (for those in Canada)

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