Midea R32 M thermal Arctic Mono fault E8

What it means

Water flow failure detected (serial number 9). Displayed on user interface and hydronic system main PCB.

Likely causes

1. Wire circuit short connected or open, water flow rate too low, water flow switch damaged, water circuit abnormal or not emptied
2. Pump failure, blocked water lines, air in system, low water level, closed isolation valves
3. Insufficient water flow rate in cooling mode
4. Insufficient refrigerant caused by refrigerant leakage
5. Low pressure side blocked by crushed or bent pipe, blocked EXV, or dirty filter
6. Poor air side heat exchanger heat exchange in heating or DHW mode

Where to start

1. Check water flow switch connection on hydronic system main PCB port CN8. Check water flow after water pump is switched on. Verify water circuit ball valve is open. Verify inlet and outlet pipes are not reversed. Verify water circuit replenishment and emptying is completed. Check pump wires connection and water pump indicator light.
2. Check pump operation, verify water circulation, inspect for blockages, bleed air from system
3. Whether the pump wires are connected and whether the water pump indicator lights up after the water pump icon is lit on the wired controller