Service manual

6-15
T-294-01
d. Removing Oil from the Compressor
1. If the oil level recorded in step a.3 is above
one-eighth level of the capacity of the sight glass,
oil m ust be removed from the compressor.
2. Close (frontseat) the manifold liquid hand valve
and pump unit down to 1.2 to 1.3 kg/cm@ (2 to 4
psig). Frontseatthe manifoldvapor handvalveand
slowly bleed remaining refrigerant.
3. Removetheoildrainplugonthebottomplateofthe
compressoranddraintheproperamountofoilfrom
the compressor to obtain t he correct level
(maximum is one-eight level of the sight glass).
Replacetheplugsecurelybackintothecompressor.
4. Repeat step (a) to ensure proper oil level.
5. Return the system to its hermetic state byreferring
to section 6.4.
6.12 FILTER-DRIER
Onunitsequippedwithawater-cooledcondenser,ifthe
sight glass appears to be flashing or bubbles are
constantly moving through the moisture liquid
indicator/sightglasswhenthesuctionmodulationvalve
isfullyopen,theunitmayhavealowrefrigerantcharge
or the filter-drier could be partially plugged.
a.
To Check Filter-Drier
1. Testforarestrictedorpluggedfilter-drierbyfeeling
the liquid line inlet and outlet connections of the
driercartridge.Iftheoutletsidefeelscoolerthanthe
inlet side, then the filter-drier should be changed.
2. A second test for moisture in the filter-drier is that
themoisture-liquidindicatorshowsmoistureinthe
system.
b.
To Replace Filter-Drier
WARNING
Residual system oil can cause a fire and
potential injury. To avoid the possibility of
an oil firewhenreplacingthefilter drieruse
the following procedure.
OilFireextinguishingsourceisREQUIRED
to be at your disposal during the repair.
NOTE
Run unit in a FULL COOL operation for 20
minutesbeforebeginningProcedure. Thiswill
circulate the majority of the oil back to the
compressor.
1. Recover refrigerant (refer to section 6.4) and
replace filter-drier. Do not allow contaminants and
moisture into the system.
2. Evacuate the unit per section 6.6.
3. After unit is in operation, inspect for m oisture in
system.
4. Remove strap from around the filter drier.
5. Using a small tube cutter, cut the liquid line just
below the moisture--line indicator. Make t he cut
just below the brazed joint of the moisture--line
indicatorandU--tube.Approximately,1inchbelow
the brazed joint. Refer to Figure 6-18.
Filter Drier
Moisture-Line
Indicator
U-tube
(needs to be pierced
to remove residual oil)
Figure 6-18. Filter-Drier and U-tube
6. Using the small tube cutter, cut t he U--tube just
below the filter drier, and remove the old U--tube
completely.
7. Allow oil to drain.
WARNING
Due to the nature of refrigeration systems,
there may be some residual oil. There is still
a potential for fire. Be prepared to
extinguish the fire.
8. Braze out the filter drier and remains of the U--tube,
use kit P/N 76 --50085--00 and braze in the new Filter
Drier and U--tube.