Mitsubishi EHST20C-VM2C - Page 70

70
No. Fault symptom Possible cause Explanation - Solution
4 LED2 on FTC is off.
(See"6.WIRING
DIAGRAM".)
<FTCpoweredonindependentsource>
1. FTCisnotsuppliedwith220to240VAC. 1. CheckthevoltageacrosstheLandNterminalsontheindoorpowersupply
terminalblock.(See"7.FIELDWIRING".)
•Whenthevoltageisnot220to240VAC,checkforfaultywiringtopower
supply.
•Whenthevoltageis220to240VAC,goto2.below.
2. There are problems in the method of
connectingtheconnectors.
2. Checkforfaultywiringbetweentheconnectors.
•Whentheconnectorsarewiredincorrectlyre-wirethem correctlyreferring
tobelow.(See"7.FIELDWIRING"andawiringdiagramonthecontroland
electricalboxcover.)
L
N
CN01
CN01
S1
S2
S3
•Ifnoproblemfoundwiththewiring,goto3.below.
3. FTC failure 3. Check the FTC control board.
•CheckthefuseonFTCcontrolboard.
•Checkforfaultywiring.
•Ifnoproblemfoundwiththewiring,theFTCcontrolboardisfaulty.
When LED1 on FTC is lit. Rechecktherefrigerantaddresssettingontheoutdoorunit.
Settherefrigerantaddressto“0”.
(SetrefrigerantaddressusingSW1(3-6)onoutdoorcontrollercircuitboard.)
Incorrectsettingofrefrigerantaddressfor
outdoor unit.
(Noneoftherefrigerantaddressissetto"0".)
5 LED2 on FTC is
blinking.
(See"6.WIRING
DIAGRAM".)
WhenLED1isalsoblinkingonFTC. CheckforfaultywiringbetweenFTCandoutdoorunit.
FaultywiringbetweenFTCandoutdoorunit
When LED1 on FTC is lit.
1. Faultywiringinmainremotecontroller
Multipleindoorunitshave been wired to a
singleoutdoorunit.
1. Checkforfaultywiringinmainremotecontroller.
Thenumberofindoorunitsthatcanbewiredtoasingleoutdoorunitisone.
Additionalindoorunitsmustbewiredindividuallytoasingleoutdoorunit.
2. Short-circuitedwiringinmainremotecontrol-
ler
2.,3. Removemainremotecontroller wires and check LED2 on FTC.(See"6.
WIRINGDIAGRAM".)
•
IfLED2isblinkingcheckforshortcircuitsinthemainremotecontrollerwiring.
•IfLED2islit,wirethemainremotecontrolleragainand:
-ifLED2isblinking,themainremotecontrollerisfaulty;
-
ifLED2islit,faultywiringofthemainremotecontrollerhasbeencorrected.
3. Main remote controller failure
6 LED4 on FTC is off.
(See"6.WIRING
DIAGRAM".)
1. SD memory card is NOT inserted into the
memorycardslotwithcorrectorientation.
1. Correctly insert SD memory card in place until a click is heard.
2. Not an SD standards compliant memory card. 2. Use an SD standards compliant memory card. (Refer to installation manual,
"5.8UsingSDmemorycard".)
LED4 on FTC is
blinking.
(See"6.WIRING
DIAGRAM".)
1. Full of data. 1. Moveordeletedata,orreplaceSDmemorycardwithanewone.
2. Write-protected. 2. Releasethewrite-protectswitch.
3. NOT formatted. 3. Refertoinstallationmanual,"5.8UsingSDmemorycard".
4. FormattedinNTFSlesystem. 4. FTCis Notcompatible withNTFSlesystem.UseanSDmemorycardfor-
mattedinFATlesystem.
7 Nowaterathottap. 1. Cold main off 1. Check and open stop cock.
2. Strainer (local supply) blocked. 2. Isolatewatersupplyandcleanstrainer.
8 Coldwaterattap. 1. Hotwaterrunout. 1. EnsureDHWmodeisoperatingandwaitforDHWtanktore-heat.
2. Prohibit, schedule timer or holiday mode se-
lected or demand control input (IN4) or smart
gridready(switch-offcommand).
2. Checksettingsandchangeasappropriate.
3. Heatpumpnotworking. 3. Check heat pump – consult outdoor unit service manual.
4. Booster heater cut-out trip
ped . 4. Check booster heater thermostat and press reset button if safe.
Resetbuttonislocatedonthesideofboosterheater,coveredwithwhiterub-
bercap.See"4.PARTNAMESANDFUNCTIONS"tondoutitsposition.
5.
Theearthleakagecircuitbreakerforbooster
heater breaker (ECB1) tripped.
5. Check the cause and reset if safe.
6. The booster heater thermal cut-out has
trippedandcannotberesetusingthemanual
reset button.
6. Check resistance across the thermal cut-out, if open then the connection is
brokenandtheboosterheaterwillhavetobereplaced.
Contact your Mitsubishi Electric dealer.
7. Immersion heater cut-out tripped. 7. Check immersion heater thermostat and press reset button, located on im-
mersionheaterboss,ifsafe.If the heater has been operated with no water
insideitmayhavefailed,sopleasereplaceitwithanewone.
8.
Immersion heater breaker (ECB2) tripped. 8. Check the cause and reset if safe.
9. 3-wayvalvefault 9. Checkplumbing/wiringto3-wayvalve.
(i)Manuallyoverride3-wayvalveusingthemainremotecontroller.(Referto
<Manualoperation>in"9-4.Servicemenu")Ifthevalvedoesnotstillfunc-
tion,goto(ii)below.
(ii)Replace3-wayvalvecoil.Ifthevalvedoesnotstillfunction,goto(iii)be-
low.
(iii)Replace3-wayvalve.(Referto"11.DISASSEMBLYPROCEDURE".)
YELLOW
YELLOW
BLACK
BLACK
Modiedsettings
(Separatepower
supply to the
cylinder unit)
Cylinder unit
control board
White
OCH570C