4-19
© 2015 Mobile Climate Control
T-367 Rev. 05/2015
g. With the clearance set, hold each set screw while
tightening the lock nuts to 7 ft/lbs.
h. Reconnect wiring and test clutch operation.
4.14.6 Compressor Oil Level
To check, and if requ ired correct, the compressor oil
level do the following:
a. Operate the coach for at least one-half hour at fast
idle speed, with the temperature controls at the
coolest setting, and the compressor fully loaded. It
may be n ecessary to pre-heat the coach and/or op
erate the system in the reheat mode to keep the
compressor fully loaded throughout this proce
dure
b. Ensure the system is fully charged (refer to para
grap h 4.7) and the compressor crankcase is warm
to the touch after fifteen minutes of operation.
c. Shut off the system and immediately reco rd the oil
level in the compressor sight glass. See
Figure 4-14. If the compressor is not level, an aver
age between the sight glass levels will have to be
made to determine level.
d. The correct oil level for this application should be
between the Min/Max of the oil level sightglass.
See Figure 4-14. If the oil level is correct, release
the coach into service. If the level is above the
sightglass m aximum, proceed to step e. If the level
is below th e sightglass m inimum proceed to step f.
e. To remove oil and bring the level between the
Min/Max sightglass markings, do the following:
1.With the system o ff, connect a m anifold gauge
set to the compressor suction and discharge ser
vice valves. Front seat th e service valves to isolate
the compressor from the system (See
Figure 4-13) and reclaim t he refrigerant to below
atmospheric pressure. Shut off the reclaimer and
verify the p ressure does not rise. If the pressure
rises, continue reclaiming until the pressure re
main s below atmospheric.
WARNING
Extreme care must be taken to ensure
that all the refrigerant has been removed
from the compressor crankcase or the re
sultant pressure will forcibly discharge
compressor oil.
2.Drain or pump out compressor oil until the lev
el is brought between the Min/Max markings.
3.Evacuate the compressor to 500 microns. Back
seat th e comp ressor service valves and repeat t h e
oil level check procedu r e.
f. To add oil to the compressor, do the following:
1.With the system o ff, connect a m anifold gauge
set to the compressor suction and discharge ser
vice valves. Front seat bo th service valves to iso
late the compressor from the system (See
Figu re 4-13) and r eclaim t he refrigerant to below
atmospheric pressure. Shut off the reclaimer and
verify the p ressure does not rise. If the pressure
rises, continue reclaiming until the pressure re
main s below atmospheric.
2.Add oil to compressor crankcase slowly,
through the oil fill plug opening (see Figure 4-14)
to bring level to mid range of allowed levels.
3.Evacuate com pressor to 500 m icrons. Backseat
compressor suction and discharge valves, start
system and recheck oil level.
4.Remove manifold gauge set.
4.14.7 Checking Unloader Operation
To check unloader op eration do the following:
a. Install a manifold gauge set as shown in
Figure 4-13. Ensure both manifold valves are
frontseated and center connection is tight on
blank fitting.
b. Midseat compressor suction service valve.
c. Disconnect the suction pressure transducer. This
will force the controller to energize the unload
er(s).
d. Start the bus and run in cooling, lower set point if
required to ensure system remains in full speed
cooling.
e. Locate the unloader connector at the compressor.
Observe manifold suction gauge while unplugging
the connector. Pressure should decrease 3 to 5 psi
(0.2 to 0.4 bar) when the unloader is unplugged
and increase the same amount as the plug is recon
nected. Repeat test for second unloader if fitted.
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