Lennox MWMB012S4-*L - Page 124

124
Error Code: P5
Description: Hightemperaturesensedatoutdoorcoil.
General Note: Whenoutdoorpipetemperatureismorethan149°F(65°C),theunitwillstop,andunitrunsagainwhenoutdoorpipe
temperatureislessthan125.6°F(52°C).
Hightemperatureprotectionof
condenser
Checkwhetherthecompressor
temperatureishigherthan149°F
(65°C)?
Istheconnectionbe-
tweenthetemperature
sensorandthePCB
correct?
No
Repair/replacewiringas
perwiringdiagram.
No
Yes
Checktheresistance
valueoftheoutdoor
temperature sensor is
correct.Refertotable
Appendix 1.
Replacethetemperature
sensor.
No
Yes
Yes
Checkwhethertheoutdoorambi-
enttemperatureishigherthan
122°F(50°C).
Switchunitoffuntilambienttem-
peratureiswithinnormaloperating
parameters.
Yes
No
Istheresufcientairowacross
outdoorunitcoils?
Removeobstructionorincrease
ventilationpath/airow.
No
Removeremainingrefrigerant
charge,pressuretestandlocate
leak.Addcorrectcharge.Test
system. If system fails to operate
correctly replace outdoor board.
Replacetheoutdoormainboard.
Yes
Aretheoutdoorunitfansoperat-
ingcorrectly?
Refertothefaultcodefanspeed
malfunction (E8).
No
Yes
Aretheoutdoorunitcoilsclean?
Cleantheoutdoorcoilthoroughly.
No
Yes
Conrmifsystemhasthecorrect
refrigerantcharge.
No
Yes