Midea M-Thermal Series - Page 74

  M‐ThermalSplit 
20190973
Figure4‐4.1:Replacinganinvertermodule

Paint a layer of thermally conductive
silicagelonthePFCmodule

Paint a layer of thermally conductive
silicagelontheIPMmodule

Situation2:L0orL4errorappearsimmediatelyafterthecompressorstartsup

L0/L4 


UVWwirebetweeninvertermoduleand
compressorisnotconnectedproperly
1

Yes
EnsureUVWwireisconnectedproperly
No

Invertermoduleisdamaged
2

Yes
Replacetheinvertermodule
3

No

Compressorhasmalfunctioned
4

Yes
Replacethecompressor
No

ReplacetheoutdoorunitmainPCB


Notes: 
1. ConnecttheUVWwirefromtheinvertermoduletothecorrectcompressorterminals,asindicatedbythelabelsonthecompressor.
2. MeasuretheresistancebetweeneachofU,VandWandeachofPandNontheinvertermodule.Alltheresistancesshouldbeinfinite.Ifanyofthemare
notinfinite,theinvertermoduleisdamagedandshouldbereplaced.Referto
 Figure4‐2.2or4‐2.4inPart4,2.1“OutdoorUnitPCBs”. 
3. Whenreplacinganinvertermodule,alayerofthermallyconductivesilicagelshouldbepaintedontheIPMmodule,IGBT,diode,brigderectifer(onthe
reversesideoftheinvertermodulePCB).RefertoFigure4‐4.1.

4. Thenormalresistancesoftheinvertercompressorare0.7‐1.5ΩamongUVWandinfinitebetweeneachofUVWandground.Ifanyoftheresistances
differfromthesespecifications,thecompressorhasmalfunctioned.


Midea CAC Confidential