KOREL M2OC-18HFN8-Q, Service Manual

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10.3.3.11 The cooling operation or heating operation does not operate.
Potential causes
●
Faulty 4-way valve
Check of 4-way, please refer to part 4 in 10.4 Trouble Criterion Of Main Parts.
10.3.3.12 When cooling, heat exchanger of non-operating indoor unit frosts.
When heating, non-operating indoor unit get warm.
Potential causes ●
Faulty EXV
●
Wire and piping connected in reverse.
Check of EXV, please refer to part 5 in 10.4 Trouble Criterion Of Main Parts.
Automatic correction of wiring/piping error:
Press the "check switch" on the outdoor unit PCB board 5 seconds until LED display "CE", which
mean this function is working, Approximately 5-10 minutes after the switch is pressed, the "CE"
disappear the wiring/piping error will be corrected, and wiring/piping is properly connected.
Check switch
LED display