Lennox MPB012S4S

132
Error Code: E4
Description: Indoor return air temperature sensor error.
General Note: Ifthevoltageislowerthan0.06Vorhigherthan4.94V,theLEDwilldisplaytheerror.
Temperaturesensorerror
Checktheconnectionsbetweentempera-
turesensorandPCB.Aretheconnec-
tionsgood?
Yes
No
No
Correcttheconnections
Checktheresistancevalueofthesensor
via Appendix 1 and Appendix 2.
Yes
Replaceindoororout-
doorPCB.
Isitnormal?
No
Replacethesensor.