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

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Troubleshooting
Electrical Control System 143
2.4.4.14. P5 malfunction
When condenser high temp. is more than 65°C, the unit will stop, and unit runs again when outdoor pipe
temp. less than 52°C.
P5 display
High temperature protection of
condenser
Check whether the
condenser temperature is
Higher than 65°C
Yes
Check whether the
resistance of condenser
temp. sensor is normal
refer to the Appendix 1
Replace the temperature sensor
No
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
Refrigerant is not enough add the
refrigerant
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
Correct the connection No
Yes
Check the connection
between temperature
sensor and PCB.
Yes