Midea M-Thermal Arctic HT R290 Mono fault E1

Phase loss or phase reversal

Heat pump

What it means

Error code E1 applies to 3-phase units and indicates phase loss or phase reversal, triggered when at least one of L1/L2/L3/N is misconnected or disconnected.

Likely causes

  1. At least one of L1/L2/L3/N misconnected or disconnected
  2. Incorrect phase sequence
  3. Faulty inverter control box
  4. Faulty inverter power module
  5. Faulty three-phase bridge rectifier (3Ph models)

Where to start

  1. Identify CN30 terminal block pins 1-10 (A, B, X/HA, Y/HB, E, T1, T2, E1, H1, H2)
  2. Confirm correct wiring of A, B, X/HA, Y/HB, E to external Modbus module terminals X1/HB, X2/HA, H1, H2
  3. Verify B-/A+/E connections to Modbus interface

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 116), right under the answer

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 M-Thermal Arctic HT R290 Mono. Check the model on the data plate before you order parts.

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