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Midea Heat pump fault H1

Communication error between main control PCB and inverter PCB

Heat pump

What it means

Communication failure occurs between the Main Control PCB and the Inverter PCB, triggered after powering on the unit for 2 minutes.

Likely causes

  1. Abnormal power supply to ODU
  2. Inverter PCB fault (LED2 off or abnormal BUS voltage)
  3. Faulty communication cable between Main Control PCB and Inverter PCB (CN43)
  4. Faulty Main Control PCB

Where to start

  1. View the slim light of LED2 through the gap at the back of the inverter PCB
  2. Identify CN30 terminal block pins 1-10 (A, B, X/HA, Y/HB, E, T1, T2, E1, H1, H2)
  3. Confirm correct wiring of A, B, X/HA, Y/HB, E to external Modbus module terminals X1/HB, X2/HA, H1, H2

The full answer, free

  • 13 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 105), 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 Heat pump. Check the model on the data plate before you order parts.

Other Midea Heat pump fault codes