User Manual

AIRSYSTEM
SecondaryAirPressureGauge
Followtheprocedurebelowto
checkthecompressedairsystem
forleaks:
1.Periodically,oraftermaintenance
orreplacementofairsystem
components:
2.Buildupairpressureinthesystem
tothegovernorcutoutpointoruntil
120psi(827kPa)isreached.
3.Stoptheengineandreleasethe
servicebrakes.
4.Withoutapplyingthebrakepedal,
observetherateofairpressure
drop.Thisrateshouldnotexceed
2.0psi(14kPa)perminute.
5.Starttheengineandbuildupthe
airpressureagain.
6.Stoptheengine,andapplythe
brakesfully.Applythebrakepedal
andholditdownforveminutes.
Thepressuredropshouldnot
exceed3.0psi(21kPa)per
minute.
7.Ifyoudetectexcessiveleakage
(airpressurelossgreaterthan3.0
psi(21kPa)afterveminutesof
brakeapplication),aleakagetest
shouldbemadeattheairline
connectionsandatallairbrake
controlunits.Thesetestsshould
determinewhereairisescaping.
AirCompressor
Operation
Allcompressors,regardlessofmake
ormodel,runcontinuouslywhilethe
engineisrunning.Systempressure
iscontrolledbythegovernor.The
governoractsinconjunctionwith
theunloadingmechanisminthe
compressorcylinderblocktostart
andstopcompressionofair.The
compressorisunloadedwhenthe
systempressurereaches120psi(827
kPa)andcompressionisreestablished
whensystempressurefallsto100psi
(690kPa).
5-64Y53-6077-1B1(03/17)
5