Navistar International LT Series - Desiccant Filter; Purge Valve; Heater; Air Reservoir; Tanks Moisture Draining

MaintenanceInstructions
Theairdryerisinstalledbetweentheaircompressordischarge
lineandtheairtanks.Theairdryerhasadesiccantcartridge
andalter,whichisservicedasanassembly.Moisturefromthe
aircollectsonthedesiccantandisautomaticallydischarged.
Lifeandperformanceoftheairdryerdependsonusage,air
humiditylevels,environmentaltemperatures,aircompressoroil
control,anddesiccantquantity.Regularlycheckthedesiccant,
purgevalve,andairdryerheaterperformance.
DesiccantFilter
Openreservoirdrainvalvesandcheckforpresenceofwater.
Smallamountsofwaterduetocondensationarenormal.Ifthe
wet,primary,orsecondarytanksarecollectinganabnormally
highamountofwaterbetweenregularairtankdrainintervals,
replacetheairdryerdesiccant.
Theairdryerdesiccantreplacementintervalmayvary;itis
generallyrecommendedthatthedesiccantbereplacedevery
12monthsforsmallairdryers,liketheBendix
®
AD-IP
®
,orevery
24monthsforlargeairdryers,liketheBendix
®
AD-9
®
orBendix
®
AD-HF
®
.Ifexperiencehasshownthatextendedorshortened
lifehasresultedforaparticularinstallation,thentheinterval
shouldbeincreasedorreducedaccordingly.
PurgeValve
Checkthatthepurgevalveopensandexpelsmoisturewhen
theairgovernorshutsofftheaircompressor.Airshouldescape
rapidlyandthenquicklystop.Ifthepurgevalvedoesnotopen
oryoucanhearaslightaudibleairleakagepastthevalvefor
longerthan30seconds,thevalvemaybestickingandshould
berebuilt.Purgevalvesmayalsostickiftheairdryerheaterhas
failedandiceiscloggingthevalve.
Heater
Checkthattheairdryerheateractivatesattemperaturesbelow
freezing.Withthevehicleinacoldenvironmentandbeforethe
engineisstarted,turnontheignitionandtouchtheairdryer
housing.Itshouldbewarmerthanothermetallicitemsonthe
vehicle.Ifsomewarmthcannotbefelt,itmayindicatethatthe
heaterelementorthewiringpoweringitshouldbeserviced.
AirReservoir/TanksMoistureDraining
Moisturetakeninwiththeairthroughthecompressorinletvalves
collectsintheairtanks.Thewettankisthersttanktoreceive
airfromtheairdryerandthereforecollectsmostoftheremaining
moisturethatwasnotremovedbytheairdryer.Drainthewet
tankreservoireverydayattheendofthetrip.Draintheprimary
andsecondarytanksperiodically.Periodically,manuallydrain
eachreservoirbyopeningthedraincocklocatedeitheronthe
bottomofthetankorintheendofthetank.
Makesurethedrainpassageisnotplugged.Foreaseof
draining,someorallairtankdrainvalvesmaybeequippedwith
optionalpullcords.Theremustbesomeairpressureinthe
systemtoensureproperdrainage.Closethedraincocksafter
allmoisturehasbeenexpelled.
Drainthewettankdailyattheendofeachtriptopurgecollected
waterandpreventiceformationinsidethetankwhenthevehicle
isshutoffincoldweather.Ifyouareunsurewhichtankisthe
wettank,drainalltanksdaily.
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