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LG Therma V fault CH43

Sensor error of high pressure

Heat pump

What it means

Abnormal value of the high pressure sensor (Open/Short condition detected by Main PCB Outdoor Cycle).

Likely causes

  1. Bad connection high pressure connector
  2. Defect of high pressure connector (Open/Short)
  3. Incorrect pipe length or amount of refrigerant
  4. Abnormal sound in outdoor unit (compressor, fan, or other components)
  5. Failure of circuit board (fan control board or main board)
  6. Fan locked
  7. Abnormal refrigerant pressure

Where to start

  1. Check if pressure sensor is OK by checking the value of pressure sensor. If not OK, replace the pressure sensor.
  2. If pressure sensor OK, check if sensor is connected to Main PCB(Outdoor Cycle) correctly. If not connected correctly, connect sensor to PCB correctly.
  3. If system is still abnormal after Main PCB replacement, replace corresponding pressure sensor.

The full answer, free

  • 7 more checks in order
  • How to put it right, step by step
  • The manual page for this fault (page 116), right under the answer
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Safety: Isolate the outdoor unit and any backup heater, and give the inverter capacitors time to discharge before you open the electrics. Anything on the refrigerant circuit needs F-gas certification.

From the LG manual for the Therma V. Check the model on the data plate before you order parts.

Other LG Therma V fault codes