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LG Therma V fault CH16

Problems in sensors (heater water temperature sensor error)

Heat pump

What it means

Heater water temperature sensor error / Water temperature sensor error occurring at the same time, indicating defects in the heater outlet temperature sensor circuit.

Likely causes

  1. Sensor mismatch on the Main PCB (Indoor, Outdoor)
  2. Main PCB (Indoor, Outdoor) defect
  3. Sensor failure (Reason of major defect)
  4. Temperature sensor maximum reached
  5. Heater out temp. sensor error
  6. Improperly connected sensor

Where to start

  1. Measure resistance across sensor terminals and compare with table value at known ambient/water temperature.
  2. Measure voltage at CN_TH3 connector pins on PCB and compare with table value.
  3. Is the sensor correctly connected to the main PCB (indoor)? If No, re-attach the sensor to the main PCB.

The full answer, free

  • 8 more checks in order
  • The readings and component tests from the manual
  • How to put it right, step by step
  • The manual page for this fault (page 92), 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