York DHP30NWB21SDCP30NWB21SDHP36NWB21SDCP36NWB21S Service Manual page 61

(6)Overload and air exhaust malfunction diagnosis (following AP1 for outdoor unit control board)
Mainly detect:
Wether the PMV is connected well or not? Is PMV damaged?
Is refrigerant leaked?
Fault diagnosis process:
20 minutes after the
complete unit is
powered off
Is the terminal FA for the
electronic expansion valve
connected correctly?
Resistances between the first four pins
close to the terminal hole and the fifth
pin are almost the same, less than 100
ohm.
Replace the electronic
expansion valve
If the fault is eliminated?
Replace the
control panel
AP1
If the fault is eliminated?
Coolant leakage, refilling
the coolant
End
Connect the
wires correctly
54