Munters ML690 - 8.3 Fault tracing list

DehumidierML420-MLT1400
8.3Faulttracinglist
ThecontrolpanelLEDaretheprimarysourceofinformationforfaulttracingwhentheunithasgivenan
alarmandstoppedautomatically.
GothroughthefaulttracinglistbelowbeforecontactingMuntersservicedepartment.Thelistcontains
informationforidentifyingfaultsthatareeasytorepairwithoutthehelpofatechnician.
IftheunitisequippedwiththehumidityregulationsystemRH98,seealsoappendix
1.6,Humiditycontrolsystem.
SymptomIndicatorsPossiblecauseCorrectiveaction
Powersupplyfailure.Checkpowersupplytotheunit.
Mainssupplyswitch(no.1)issetto
”0”.
Setthemainssupplyswitchto”1”andcheckthatthemains
connectionindicator(no.14)ison.
TransformerTC25fuseFU26
failure.
Investigatethecauseofthefaultandrectify.Replacethefuse.
Unithas
stopped.
Nolights.
CircuitbreakerQM25trippeddue
toawiringfault.
Investigatethecauseofthefault,andrectify.
ResetQM25.Ifthefaultre-occurs,contactMunters.
Theunithasbeensetto
AUTomaticmodebymistakewith
nohumiditysensorconnected.
SetthemodeswitchtoMANual,andcheckthattheunitstarts. Unithas
stopped.
No.12
doesnot
ash.
Humiditysensorfault(AUTomatic
mode).
SetthemodeswitchtoMANual,andcheckthattheunitstarts.Ifthe
unitstarts,thefaultisprobablyinthehumiditysensor.
SetthemodeswitchtoAUTomaticmode,andcheckthehumidity
sensorbyseeingifthedehumidierstartswhenthehumiditysensor
setpointisreduced.Thenresetthehumiditysensorsetpoint.
Calibratethehumiditysensor(accordingtothemanufacturer's
recommendations)ifnecessary,orreplaceit.
Unithas
stopped.
No.12,6
and7are
ashing.
Ifbothindicatorsareashing,
itindicatesthatone(orboth)of
thehightemperaturecut-outs
(BT27andBT30)havetripped,
duetoeitheranobstructioninthe
reactivationairow,orbecausethe
reactivationairowhasbeenset
toolow.
Switchoffthemainssupplyandallowtheunittocooldown.
ResetQM12andQM14circuitbreakersasrequired.
Checkthattheairinlet,outletductsandltersarefreefrom
obstructionsandarenotblockedwithdirt.
Switchonthemainssupplyatthemainssupplyswitchtoresetthe
faultwarning.Checkandadjustthereactivationairow,seesection
5.3,Airowcheckandadjustment.
Switchoffthemainssupplyandallowtheunittocooldown.
Investigatethecauseofthefault,andrectify.
ResetQM12andQM14asrequired.
Unithas
stopped.
Either
No.12,6
and7are
ashing.
Safetydeviceshavetrippeddueto
aheaterelementorwiringfault.
Switchonthemainssupplyatthemainssupplyswitchtoresetthe
faultwarning.
190TGB-1035-H1604Faulttracing29