True GDM-49 - Page 29

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True Food Service Equipment, Inc.
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INSTALLATION / OPERATION INSTRUCTIONS
4.Ifalloperatingconditionsarenormal,
thevoltagesupplyatthecompressor
terminalsbalancedandwithinlimits,the
compressorcrankcasetemperaturewithin
normallimits,andtheamperagedrawn
withinthespecifiedrange,themotor
protectormaybedefective,andshould
bereplaced.
Iftheoperatingconditionsarenormal
andthecompressorisrunningexcessively
hotfornoobservablereason,orifthe
amperagedrawnisabovethenormal
rangeandsufficienttorepeatedlytripthe
protector,thecompressorhasinternal
damageandshouldbereplaced.
IF THE COMPRESSOR RUNS
BUT WILL NOT REFRIGERATE
1.Checktherefrigerantcharge.Check
theevaporatorsurfacetodetermine
ifitisevenlycoldthroughout,orif
partiallystarved.Alackofchargemay
beindicatedbylight,fluffyfrostat
theevaporatorinlet.Addrefrigerantif
necessary.
2.Checkthecompressorsuction
pressure.Anabnormallylowpressure
mayindicatealossofrefrigerantcharge,
amalfunctioningcapillarytube,alackof
evaporatorcapacitypossiblyduetoicing
orlowairflow,orarestrictioninthe
system.
Oftenarestrictioninadrierorstrainer
canbeidentifiedbyfrostoradecrease
intemperatureacrosstherestrictiondue
tothepressuredropintheline.Thiswill
betrueonlyifliquidrefrigerantisin
thelineattherestrictedpoint,sinceany
temperaturechangeduetorestriction
wouldbecausedbytheflashingofliquid
intovaporasthepressurechanges.
Anyabnormalrestrictioninthesystem
mustbecorrected.
3.Checkthecompressordischarge
pressure.Anabnormallyhighdischarge
pressurecancausealossofcapacity,and
canbecausedbyadirtycondenser,a
malfunctioningcondenserfan,orairin
thesystem.
4.Ifthesuctionpressureishigh,
andtheevaporatorandcondenser
arefunctioningnormally,checkthe
compressoramperagedraw.Anamperage
drawnearorabovethenameplaterating
indicatesnormalcompressororunitmay
havedamagedvalves.
Anamperagedrawconsiderablybelow
thenameplateratingmayindicate
abrokensuctionreedorbroken
connectingrodinthecompressor.
IF THE MOTOR COMPRESSOR
STARTS BUT TRIPS
REPEATEDLY ON THE
OVERLOAD PROTECTOR
1. Defrost Time Clock
 A. Checktimermotortobe
  sureitruns.
 B. Checkcontactsonthe 
  defrosttimer.
 C.Checksolenoidwindings
  forcontinuitytoensure
  contactswitching.
 D.Checktobesuredefrost
  actuatorpinsareinproper
  position.
 E. Checkallwiresinthetimer
  fortightnesstoterminalsand
  brokenwires.
2. Defrost Control On The
Evaporator Drain Pan
A.Ifthedefrosttimeisalways35
minutes(orwhateverdurationthe
elapsedtimeadjustmentissetat)and
thefanmotorsdonotdelayaftera
defrostcycleandithasbeendetermined
thatthesolenoidinthedefrostclockis
functioning,changethedefrostcontrol
intheevaporatorcompartmentin
thetopofthefreezer.Thiscontrolis
attachedtotheevaporatordrainpan.
3. Coil Defrost Heater
 A.Lowertheevaporatorcover.
Disconnectthecoilheaterbyremoving
thewirenutsatthepointwherethe
heaterjoinstheelectricalcircuitofthe
freezerintheevaporatorcompartment.
Checkheaterforcontinuitywithan
ohmmeter.Iftheheaterisdefective,cut
thebalewiresholdingtheheatertothe
coilandremovetheheater.Replacewith
anewheaterusingbalewiresprovided.
4. Drain Tube Heater
 A.Lowertheevaporatorcover.
Disconnectthedraintubeheaterby
removingthewirenutsatthepoint
wheretheheaterjoinstheelectrical
circuitofthefreezerintheevaporator
compartment.Checkthedraintube
heaterwithanohmmeter.
 B.Ifthedraintubeheateris
defective,disconnectthedraintubefrom
therigidplasticdrain,bendthetabsthat
holdtheevaporatordrainpantothe
evaporatorcoverandraisethedrainpan
sothattheflexibleheaterisvisible,pull
heateroutoftheplasticdraintubeand
replace.Connectheatertotheelectrical
circuitintheevaporatorcompartment.
5. Cabinet Temperature Control
 A.Removethetwoscrewson
therightsideoftheevaporatorhousing
thatholdsthecontrolmountingplate.
Reachbehindtheevaporatorhousingon
thecontrolsideofthecabinetandpull
thecontrolbulboutofthereceptaclein
theroofofthecabinet.Disconnectthe
wiresfromthecontrol.Checkcontrol
forcontinuity,replaceifdefective.