4-9
T-312
4.12.2 Re--installing the Compressor
NOTES
1. The
service
replacement
05G
compressors are sold without shutoff
valves. Valve pads are installed in their
place. The optional unloaders are not
supplied, as the cylinder heads are shipped
with plugs. The customer should retain the
original unloader valves for use on the
replacement compressor.
2. The piston plug that is removed from the
replacement compressor head must be
installed in the failed compressor if
returning for warranty.
3. Do not interchange allen head capscrews
that mount the piston plug and unloader;
they are not interchangeable.
4. Check oil level in service replacement
compressor. (Refer to paragraphs 1.3 and
4.12.4)
5. Service replacement compressors are
supplied with a suction filter sock for initial
startup. Ensure the filter sock is installed
and removed in accordance with the
instructions furnished.
a. Remove the three socket head capscrews from both
unloader valves on the side heads of the 05G
compressor. Remove the unloader valve and bypass
piston assembly, keeping the same capscrews with
the assembly. (See Figure 4-8) The original unloader
valve must be transferred to the replacement
compressor. The plug arrangement removed from
the replacement is installed in the original
compressor as a seal. If piston is stuck, it may be
extracted by threading a socket head capscrew into
top of piston. A small Teflon seat ring at the bottom of
the piston must be removed.
GASKET
BYPASS
PISTON
PLUG
SPRING
FLANGE
COVER
CAPSCREWS
COMPRESSOR
HEAD
(NOT INTERCHANGEABLE WITH
CONTROL VALVE SCREWS
)
Figure 4-8. Removing Bypass Piston Plug
b. Remove the high pressure switch and pressure
transducer assemblies and install on replacement
compressor after checking switch operation.
c. Install compressor in unit by performing steps c.
through g. in reverse sequence. It is recommended
that new locknuts be used when replacing
compressor. Install new gaskets on service valves
and tighten bolts uniformly.
d. Re--install and tension the compressor drive belt.
e. Unlock and turn main battery disconnect switch to ON
position..
f. Attach two lines (with hand valves near vacuum
pump) to the suction and discharge service valves.
g. Fully backseat (open counterclockwise) both suction
and discharge service valves.
h. Remove vacuum pump lines and install manifold
gauges.
i. Start unit and check refrigerant level. (Refer to
paragraph 4.7.1)
j. Check compressor oil level. (Refer to paragraph
4.12.4) Add or remove oil if necessary.
k. Check compressor unloader operation.
4.12.3 Compressor Unloaders
Although the electric unloaders are non--adjustable,
they will require some periodic maintenance. Service
kits are available for repair of the electric unloaders
solenoid and stem assemblies.
To check the unloaders proceed as follows:.
a. Ensure that the compressor is fully loaded. Heat the
interior of the coach if necessary.
1. Electric Unloader
Valve
2. Suction Service
Valve Charging Port
3. Suction Service
Valve
4. Clutch
5. Oil Fill Plug
6. Bottom Plate
7. Oil Drain Plug
8. Oil Level Sight
Glass
9. Oil Pump
10. O’Ring
11. Discharge Service
Valve
12. Service Port
1
2
3
4
5
6
7
8
9
10
11
12
Figure 4-9. Model O5G Compressor
b. Connect manifold guages to the compressor.
c. Slowly frontseat the suction valve until 26 psig shows
on the suction guage. The first unloader should
energize (check for magnetism at the unloader coil)
increasing suction pressure by 3 to 5 psig.
d. Slowly open the suction valve until the suction gauge
reads 32 psig. The first unloader should de--energize
decreasing suction pressure by 3 to 5 psig to show it
is operating properly.
e. To check the second unloader, continue to frontseat
the suction valve until 21 psig shows on the suction