York HP Series Service Manual page 106

16.4.8 Over-voltage or under-voltage protection diagnosis and solution (P1)
Error Code
Malfunction conditions
Potential causes
Trouble shooting:
P1
Abnormal increases or decreases in voltage are detected by
checking the specified voltage detection circuit.
Power supply issues
●
System leakage or blockage
●
Faulty PCB
●
103
Remark:
Measure the DC voltage
between P and N port.
The normal value should
be around 310V.340V or
380V