Midea M-Thermal Series - Page 46

  M‐ThermalSplit 
20190945
Procedure

E2 


CommunicationwiresXYEhaveshort
circuited,disconnectedorare
misconnected
1

Yes
Reconnectthecommunicationwires
No

CommunicationwiresXYEarenot
connectedinadaisychain
Yes
Connectthecommunicationwiresina
daisychain
No

WiresbetweenhydronicboxmainPCB
andelectriccontrolboxcommunication
terminalsblockareloose
Yes
Ensurethewiresareconnectedproperly
No

Interferencefromhighvoltage(220Vor
higher)wires
Yes
Ensurethecommunicationwiresand
highvoltagewiresareseparated
No

Communicationwiresareclosetoa
sourceofelectromagneticradiationsuch
astransformerorstrongfluorescentlamp
Yes
Removethesourceofinterference,or
addadditionalshieldingtothe
communicationwires
No

Replacingelectriccontrolbox
communicationterminalsblockresolves
theerror

No

ReplacehydronicboxmainPCB  

Notes: 
1. Measuretheresistanceamong X,Yand E.ThenormalresistancebetweenPandQis120Ω,betweenPandEisinfinite,betweenYandEisinfinite.
Communicationwiringhaspolarity.EnsurethattheXwireisconnectedtoXterminalsandtheYwireisconnectedtoYterminals. 
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