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Midea R32 M thermal Arctic Mono fault L4

MCE error

Heat pump

What it means

MCE error detected by refrigerant system main PCB. Displayed as P6/H4 on user interface.

Likely causes

  1. Compressor is over-current
  2. Inverter PCB has malfunctioned
  3. Inverter module damaged
  4. Motor control error
  5. Discharge temperature exceeding 105°C indicating high compressor load or high ambient/system conditions
  6. Crushed or bent pipe
  7. Blocked EXV
  8. Dirty filter
  9. Compressor current exceeding Currentmax threshold

Where to start

  1. Restart unit
  2. Use clip-on ammeter to measure compressor current
  3. Measure the resistance between each of U, V and W and each of P and N on the inverter module

The full answer, free

  • 29 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 67), 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 Midea manual for the R32 M thermal Arctic Mono. Check the model on the data plate before you order parts.

Other Midea R32 M thermal Arctic Mono fault codes