Service manual

16
Service Information
Toachievetherequiredlevelsofevacuation,a
properlymaintainedtwostagevacuumpumpin
goodconditionisrequired.Itisabsolutelyessential
tomaintainyourvacuumpumpaccordingtothe
manufacturer’sinstructionsincludingrequired
oilchangesattherecommendedintervals.
Vacuumpumpoilshouldalwaysbechangedafter
evacuatingacontaminatedsystem.
Vacuumpumpperformanceshouldbechecked
periodicallywithamicrongauge.
1.  Makecertainthatchargingcylindervalve,
handshut-offvalve,andmanifoldgauge
valvesareclosed.
2.  Startvacuumpump.
3.  Openhandshut-offvalveandslowly
openbothmanifoldvalves,turning
counterclockwise,fortwofullrotations.
WARNING
R-134a systems are particularly susceptible
to moisture contamination which can only
be prevented by evacuating the system for a
minimum of 30 minutes to attain a minimum
29.9 inch (500 micron or lower) vacuum.
4.  Operatethevacuumpumpforaminimum
of30minutestoaminimumof29.9”(500
micron)vacuum.
NOTE
OnproductswithLowsideleaksyoumustheat
thecrankcaseareaofthecompressorthough
outthe30minutesyouarerunningyourvacuum
pumptopullavacuumonthesystem.Every4
to5minuteswhileyouarerunningyourvacuum
pumpandheatingthecrankcaseareashake
thecompressor.Byheatingthecrank-caseyou
areheatingtheoilinthecompressor.Thiswill
drivethemoistureoutoftheoil.Byshakingthe
compressorthiswillallowthemoisturetocometo
thetopoftheoilfastersothevacuumpumpcan
removethemoisturefromthesystem.
CAUTION
If high vacuum equipment is used, just
crack both manifold valves for a few minutes
and then open slowly for the two full turns
counterclockwise. This will prevent the
compressor oil from foaming and being drawn
into the vacuum pump.
Evacuating SystemEquipment Needed for Evacuation &
Recharging:
•  Heatedchargingcylinder
•  Standard3-portmanifoldgaugeset:
 -4charginghoses
 -Teettingwithvalvecorestemremoved
(RobinairNo.40396)
 -Handshut-offvalve(RobinairNo.40380)
•  Twostagevacuumpump
•  Processtubeadapterkit(RobinairNo.
12458)
•  Tubingcutter
•  Pinch-offtoolcapableofmakingleakproof
seal
•  Completebrazingtorchset
•  Small3-cornerle
•  GritclothorScotch-Brite
•  45%silversolderandux
•  HeatGun
Installing Evacuation and Recharging
Equipment
1.  Disconnectrefrigeratorfromelectricalsupply.
2.  Ifcompressorwasreplaced,installcorrect
sizedprocesstubeadaptoronprocesstube.
Ifcompressorwasnotreplaced,cutprocess
tubewithtubingcutterleavingasmuchtube
aspossibleandinstallcorrectsizeprocess
tubeadaptor.
3.  Installcorrectsizedprocesstubeadaptoron
high-sideprocesstube.
4.  Attachrefrigerationservicegaugemanifold
tosysteminfollowingorder:
 • Low-side(compoundgauge)hosetosuction
sideprocesstubeadaptor.
 • High-side(pressuregauge)hosetohigh-side
processtubeadaptor.
 • Centerportmanifoldhosebeforehandshut-
offvalvetochargingcylinder.
 • Centerportmanifoldhoseafterhandshut-off
valvetovacuumpump.