Midea M-Thermal Arctic HT R290 Mono fault E0

What it means

Water flow failure detected before pump activation. Triggered by 5 consecutive no-water detection failures in a row before pump on, or 10 consecutive E8 occurrences in a row during running-water detection after pump on.

Likely causes

1. No water flow before the pump starts (e.g. external pump still running/interfering)
2. Incorrect dip switch configuration for pump type
3. Water flow restriction or blockage
4. Air in water system
5. Flow switch leak due to faulty sealing ring
6. External pump starts before internal pump (PUMPI) starts
7. The water flow in the pipe is not consistent with arrow on the flow switch
8. Flow switch FS plug (CN8) is not connected properly
9. Water flow switch rake mechanically damaged
10. Flow switch not installed properly
11. Water flow switch mechanically damaged (rake does not trigger contact closure)
12. Pump stalling due to impeller obstruction
13. Water pump internal failure despite correct wiring
14. Water pump malfunction indicated by abnormal indicator light status
15. Water pump leak due to faulty sealing ring
16. Water pump connection is correct, the water pump icon on the User Interface is lit, while no indicator lights on water pump is lit
17. Pump idling
18. Pump idling due to insufficient water/air in circuit

Where to start

1. Locate water flow switch, water pump, air purge valve, water inlet and water outlet using this layout when diagnosing E0/E8 faults
2. Verify DIP switch S2 positions 3/4 match installed pump type
3. Locate CN28 PUMP connector to check power supply to water pump