York DHP30NWB21SDCP30NWB21SDHP36NWB21SDCP36NWB21S Service Manual page 58

(3)High temperature and overload protection diagnosis (AP1 hereinafter refers to the control board of the outdoor unit)
Mainly detect:
Is outdoor ambient temperature in normal range?
Are the outdoor and indoor fans operating normally?
Is the heat dissipation environment inside and outside the unit good?
Fault diagnosis process:
Is outdoor ambient temperature higher than 53?
51
Overheat and high
temperature protection
N
20 minutes after the complete
unit is powered off.
Is heat dissipation of the indoor unit
and outdoor unit abnormal?
N
Does the outdoor fan work normally?
Y
Replace the
control panel AP1
End
Normal protection, please operate
it after the outdoor ambient temp-
Y
erature is normalized.
Improve the heat
Y dissipation environ-
ment of the unit
1. Check if the fan terminal OFAN
is connected correctly
2. Unplug the fan hub and using
N
an Amp meter set to Ohms,
measure resistance between
any two terminals ensuring
resistance is less than 1 Kohm
Y
N
Replace the
outdoor fan