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

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Troubleshooting
140 Electrical Control System
2.4.4.11. P2 malfunction
(Only for 36K~48K)
P2 display
Low pressure protection
Whether the wiring
between the low pressure
protector and main control
board is connected well or
correctly
Method: Disconnect the plug.
Measure the resistance of the
low pressure protector. If the
protector is normal the value is
o
Yes
Yes
Connect it well
Replace outdoor main board
No
Replace low pressure protector
No
Whether the low
pressure protector
is broken
Check whether the outdoor
ambient temperature is too
low
No
Stop the unit Yes
Open fully valve core of
high pressure valve
No
Check whether valve core
of high p
ressure
valve is
opened
Check if the indoor fan runs
properly in cooling mode
please refer to the solution of fan
speed has been out of control
malfunction. Find out the cause and
have it solved.
No
Yes
Yes
No
Check whether the refrigerant
system is ok
Refrigerant is not enough add the
refrigerant
No