North American HVAC MOC-12HFN1-MS0W, Service Manual

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Troubleshooting
Electrical Control System 141
2.4.4.12. P3 malfunction
P3 display
Current protection of compressor
The protection occurred in
standby
Yes
Yes
Measure whether the
current is normal ？
Yes
No
Replace the outdoor main PCB
Check whether the power
voltage is normal.
Measure whether outdoor
terminal voltage is normal
？
Restart the unit when the power
supply gets normal
No
Yes
No Reconnect it well
Yes
Measure whether the voltage
between L and N is normal
？
Yes
Measure whether input voltage
of bridge rectifier is normal ？
No
No
Check the wiring of
power wires well or
correctly
Reconnect it well
Check the wiring of
L and N well or
correctly
Reconnect it well
Check the wiring of
bridge rectifier well
or correctly
No
No
Yes
Replace the PFC module(If has)
No
Measure whether the voltage
between P and N is normal
refer to the Appendix 3
？
Replace the bridge
rectifier
No
Check whether
bridge rectifier is
normal
Check the wiring of
reactor or inductance
Reconnect the
wiring
No
Check whether reactor
or inductance is normal
Yes
Replace reactor or
inductance
No
Check whether the outdoor
ambient temperature is
higher than 50 ℃
No
Stop the unit Yes
Check if the outdoor unit
ventilation is good
Yes
Make the outdoor unit ventilate well
Check whether the heat
exchanger is dirty
No
Clean the heat exchanger Yes
Check whether the refrigerant
system is ok
Replace outdoor main
board
No
No
Check if the outdoor fan
runs properly
please refer to the solution of fan
speed has been out of control
malfunction . Find out the cause and
have it solved.
No
Yes
No
Yes
Yes
Check whether system pressure
is too high
Recycle the over charged
refrigerant
Yes