Lennox MPB012S4S

148
Error Code: P4
Description: Compressor drive error
General Note: An abnormal inverter compressor drive is detected by a special detection circuit, including communication signal detection,
voltage detection, compressor rotation speed signal detection and etc
CompressorDriveError
Checkwiringconnectionsbetweencompressorand
mainPCB.
No
Makenecessarycorrections.
Yes
ChecktheIPM
ReplacetheIPMboardorreplacethe
mainPCB.
No
Yes
Checktheoutdoorfanandtheoutdoorunitventilation.
Refertotheerrorcodefanspeedmal-
function (E8).
No
Yes
Checkthecompressorresistancevalues.
Replacethecompressor.
No
Yes
ReplacetheoutdoormainPCB.
Error Code: P5
Description: Modeconict.
General Note: Theindoorunitscannotworkcoolingmodeandheatingmodeatthesametime.Heatingmodehaspriority.
• SupposeindoorunitAworkingincoolingmodeorfanmode,andindoorunitBissettoheatingmode,thenAwillchange
tooffandBwillworkinheatingmode.
• SupposeindoorunitAworkinginheatingmode,andindoorunitBissettocoolingmodeorfanmode,thenBwillchange
tostandbyandAwillbenochange.
Cooling mode Heating mode Fan Off
Cooling Mode No Yes No No
Heating Mode Yes No Yes No
Fan No Yes No No
Off No No No No
No=Nomodeconict.
Yes=Modeconict