Mitsubishi EHST20C-VM2C User Manual

63
10-4. Self diagnosis and action
CheckifDIPSWissetcorrectly.(Referto"6-19.DIPswitchfunctions".)
Error code Title and display conditions Possible Cause Diagnosis and action
L3 Circulation water temperature overheat
protection
<DHW/Heating/Cooling/LP/FS/OS>
ErrorcodedisplayedwhenTHW1detectsa
temp.≥80ºCfor10consecutivesecondsor
THW2detectsatemp.≥80ºCfor10consecutive
seconds.
DHW :Domestichotwatermode
Heating :Heatingmode
Cooling :Coolingmode
LP :Legionellapreventionmode
FS :Freezestat
OS : Operation stop
TH1A/B : Room temp. thermistor
TH2 :Liquidrefrigeranttemp.thermistor
THW1 :Flowwatertemp.thermistor
THW2 :Returnwatertemp.thermistor
THW5 :Tankwatertemp.thermistor
THW6 :
Zone1owwatertemperaturethermistor
THW7 : Zone1returnwatertemperaturethermistor
THW8 : Zone2owwatertemperaturethermistor
THW9 : Zone2returnwatertemperaturethermistor
THWB1 : Boilerflowwatertemperaturethermistor
THWB2 : Boilerreturnwatertemperaturethermistor
1.
Insufcientsystemhead
1
Refertotablein"10-6.CheckingCom-
ponentParts'Function"todetermineif
system pump meets requirements.
If more head required either add a pump
ofthesamesizeorreplaceexistingpump
withcapacitymodel.
See"11.DISASSEMBLYPROCEDURE"
forhowtoreplacepump.
2.
Reducedowinprimarywatercircuit
Dueto1ormoreofthefollowing;
Faultypump,insufcientairpurge,
blockedstrainer,leakinwatercircuit.
2.
Checkcirculationpump(See"10-6.Check-
ingComponentParts'Function"forhowto
check).
Openpurgevalvetoremovetrappedair.
Checkthestrainerforblockages.
Checktheprimarywatercircuitforleaks.
Checkthattheowamountiswithinthe
recommendedrange.
3.
Valve operation fault
3.
Checkvalvesonprimarywatercircuitare
installed level.
4.
2-wayvalve(localsupply)actuator
fault
4.
Electrically test to determine fault
5.
3-wayvalveactuatorfault
5.
1) Electrically test to determine fault.
2)Operate3-wayvalvemanuallyusing
the main remote controller. (Refer to
<Manualoperation>in"9-4.Service
menu".)
3)Replace3-wayvalvecoil.
4)
Replace3-wayvalve.(RefertoProcedure
6 in “11. DISASSEMBLY PROCEDURE.”
6.
Booster heater relay (BHC1, BHC2,
BHCP)operatingfault
6.
Electrically test the relays (BHC1, BHC2,
BHCP) to determine fault.
See"10-6.CheckingComponentParts'
Function"forhowtocheck.
7.
Powersupplyvoltageincrease
7.
Checkthesupplyvoltage.
8.
THW1 or THW5 has become de-
tached from its holder.
8.
Visually inspect location and reattach as
necessary.
9.
THW1 or THW2 fault
9.
Checkresistanceofthermistoragainst
tablein"10-6.CheckingComponentParts'
Function".
Compare FTC detected temperature to
hand held detector.
10.
FTC board failure
10.
Replace board.
L4
Tank water temperature overheat protection
<DHW/Heating/Cooling/LP/FS/OS>
ErrorcodedisplaywhenTHW5detectsa
temp.≥75ºCfor10consecutiveseconds.
1.
3-wayvalveactuatorfault
1.
1) Electrically test to determine fault.
2)Operate3-wayvalvemanuallyusing
the main remote controller. (Refer to
<Manualoperation>in"9-4.Service
menu".)
3)Replace3-wayvalvecoil.
4)Replace3-wayvalve.(RefertoProcedure
6 in “11. DISASSEMBLY PROCEDURE.”
2.
Immersion heater relay (IHC) operat-
ingfault
2.
Check immersion heater relay (IHC).
3.
THW5 fault
3.
Checkresistanceofthermistoragainst
tablein"10-6.CheckingComponentParts'
Function".
Compare FTC detected temperature to
hand held detector.
4.
FTC board failure
4.
Replace board.
OCH570C

Mitsubishi EHST20C-VM2C Specifications

General

Brand	Mitsubishi
Model	EHST20C-VM2C
Category	Heat Pump
Language	English