4-wayvalvetroubleinheatingmode
Abnormal points and detection methods Causes and checkpoints
Abnormalif4-wayvalvedoesnotoperateduringheatingoperation.
Abnormalwhenanyofthefollowingtemperatureconditionsissatisedfor
3min.ormoreduringheatingoperation
1.TH22j−TH21j
[
−10°C[−18°F]
2.TH23j−TH21j
[
−10°C[−18°F]
3. TH22j
[
3:[37.4°F]
4. TH23j
[
3:[37.4°F]
Note:
Forindoorunit,theabnormalityisdetectedifanoperatingunitsatisesthe
condition.
4-wayvalvefailure
Disconnectionorfailureof4-wayvalvecoil
Cloggeddrainpipe
Disconnection or loose connection of connectors
Malfunctionofinputcircuitonoutdoormulticontrollercircuitboard
Defectiveoutdoorpowercircuitboard
TH21:Indoorintaketemperaturethermistor(RT11orTH1)
TH22:Indoorliquidpipetemperaturethermistor(RT13orTH2)
TH23:Indoorgaspipetemperaturethermistor(TH-AtoE)
●Diagnosisofdefectives
MakesuretoturnthepowerOFFbeforeconnecting/disconnectinganyconnectors,orreplacingboards.
Diagnosis Remedy
Is the connector for outdoor multi
controllercircuitboardor4-wayvalve
coil disconnected or loose?
Reconnect the connector or connect it
tightly.
Yes
Disconnect the connector for outdoor multi
controllercircuitboardor4-wayvalvecoil
to check the resistance.
No
Replacethe4-wayvalvecoil.
Replacetheoutdoormulticontrollercircuit
board.
Is the detected voltage normal?
Is it free from any trace of over-heating
or burning?
Is there a resistance detected?
Checkthevoltageandappearanceofthe
outdoor multi controller circuit board.
No
No
Yes
1508
(EF)
Yes
Replacetheoutdoormulticontrollercircuit
board.
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