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g. Noting the position of the wire, remove the three bolts
holding the coil to the compressor.
h. Remove every other bolt from the seal cover of the
new compressor in the same manner as the original
compressor. Mount the coil assembly with the wire in
the same orientation as it was mounted on the original
compressor. Tighten the mounting bolts to 45--50 ft/
lbs (5.53--6.92 mkg).
i. Mount the rotor on the shaft. Seat the rotor to the hub,
using the rotor nut. Be sure pulley turns freely without
binding. Tighten rotor nut by first noting torque neces-
sary to start the nut on the hub and then adding 50 ft/
lbs (6.92 mkg) of torque.
j. Install armature on shaft using original key and tight-
en mounting bolt to 20 ft/lbs (2.8 mkg).
k. Perform a check of the air gap between the inside
face of the armature and the mating face of the rotor.
The air gap should be measured with a minimum of 30
psig (2.04 bar) in the crankcase. A preliminary check
may be performed before the crankcase is pressur-
ized but a final check must be performed before the
clutch is operated. The gap should be between 0.030
and 0.060 inch (7.62 to 15.24 mm).
l. Loosen each of the three lock--nuts with a 7/16" box
wrench while holding the jacking screws with a 1/8"
hex socket wrench.
m. Back off the three jacking screws until they do not
touch the armature plate.
n. Turn the jacking screws clock--wise until they make
contact with the armature plate and then one and one
half more turns after contact.
o. Measure the initial clearance, the gap should be
between .030" and .060". All three set screw locations
should be very close in clearance dimensions.
p. With the clearance set, hold each set screw while
tightening the lock nuts to 7 ft/lbs.
q. Reconnect wiring and test clutch operation.
4.14.4 Compressor Oil Level
To check, and if required 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 cool-
est setting, and the compressor fully loaded. It may
be necessary to pre--heat the coach and/or operate
the system in the reheat mode to keep the compres-
sor fully loaded throughout this procedure
b. Ensure the system is fully charged (refer to paragraph
4.7.1) and the compressor crankcase is warm to the
touch after fifteen minutes of operation.
c. Shut off the system and immediately record the oil
level in the compressor sight glass. See Figure 4-11.
If the compressor is not level, an average between
the sight glass levels will have to be made to deter-
mine level.
d. The correct oil level for this application should be be-
tween the bottom and 1/2 of the oil level sightglass.
See Figure 4-11. If the oil level is correct, release the
coach into service. If the level is above the 1/2 sight-
glass maximum, proceed to step e. If the level is be-
low the 1/2 sightglass maximum proceed to step f.
03/11
e. To remove oil and bring the level to the 1/2 sightglass
maximum, do the following:
1. With the system off, connect a manifold gauge set to
the compressor suction and discharge service
valves. Front seat the service valves to isolate the
compressor from the system (See Figure 4-4) and
reclaim the refrigerant to below atmospheric pres-
sure. Shut off the reclaimer and verify the pressure
does not rise. If the pressure rises, continue reclaim-
ing until the pressure remains below atmospheric.
Extreme care must be taken to ensure that
all the refrigerant has been removed from
the compressor crankcase or the resultant
pressure will forcibly discharge compres-
sor oil.
2. Drain or pump out compressor oil until the level is
brought to or just below the 1/2 sightglass maximun.
3. Evacuate the compressor to 500 microns. Backseat
the compressor service valves and repeat the oil lev-
el check procedure.
f. To add oil to the compressor, do the following:
1. With the system off, connect a manifold gauge set to
the compressor suction and discharge service
valves. Front seat both service valves to isolate the
compressor from the system (See Figure 4-4) and
reclaim the refrigerant to below atmospheric pres-
sure. Shut off the reclaimer and verify the pressure
does not rise. If the pressure rises, continue reclaim-
ing until the pressure remains below atmospheric.
2. Add oil to compressor crankcase slowly, through the
oil fill plug opening (see Figure 4-11) to bring level to
mid range of allowed levels.
3. Evacuate compressor to 500 microns. Backseat
compressor suction and discharge valves, start sys-
tem and recheck oil level.
4. Remove manifold gauge set.
4.14.5 Checking Unloader Operation
To check unloader operation do the following:
a. Install a manifold gauge set as shown in Figure 4-5.
Ensure both manifold valves are frontseated and cen-
ter connection is tight on blank fitting.
b. Midseat compressor suction service valve.
c. Disconnect
the
(Figure 1-9, 23). This will force the controller to ener-
gize the unloader(s).
d. Start the bus and run in cooling, lower set point if re-
quired 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.
f. If pressures do not react as described, check unload-
er coil or repair unloader mechanism as required.
g. When testing is complete, reconnect transducer and
unloader connectors and remove manifold gauge set.
4--11
WARNING
suction
pressure
transducer
T356
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