Removing Oil From The Compressor; Unloader Checkout Procedure; Unloader Coil Replacement; Figure 8−24 Unloader Coil - Carrier VECTOR 6500 Operation & Service Manual

pressor suction service valve port and connect the
common connection to a vacuum pump. Remove
the discharge hose from the manifold gauge set;
connect the end with the Schrader depressor to the
compressor oil fill port (Item 12, Figure 8−19), and
immerse the other end in a container of refrigeration
oil. Start the vacuum pump throttle the manifold
gauge set suction valve and pull a vacuum on the
compressor while watching the the oil level in the
glass. Fill to 1/4 glass. Shut down pump and remove
oil fill line from the oil fill port.
3. Break any remaining vacuum (raise to 0 psig/bar)
with refrigerant remaining in the system (crack open
the suction service valve), or from a fresh cylinder of
refrigerant. Evacuate the compressor crankcase to
500 microns. Remove service equipment, backseat
suction and discharge service valves and recheck oil
level.
c. Removing Oil From The Compressor
1. Check compressor oil level, refer to preceding step a.
If the oil level is above the middle of the sight glass
(item 11, Figure 8−19), oil must be removed from the
compressor.
2. Pump down the compressor. Refer to Section 8.6.2.
3. Ensure the unit will not start automatically by dis-
abling any two way communication and placing the
Main Power switch in the OFF position. Disconnect
the high voltage source and lockout/tagout the re-
ceptacle.
4. Loosen the oil drain plug (item 10, Figure 8−19) and
allow oil to seep out and bring the level to 1/8 glass.
Tighten the plug securely back into the compressor.
5. Leak check the oil drain plug, refer to Section 8.6.3.
Start compressor and recheck oil level
8.7.6 Unloaders
a. Unloader Checkout procedure
1 Install a manifold gauge set on the compressor suc-
tion and discharge service valves and start unit in
cooling with compartment temperatures at least 5_F
(2.8_C) below set point. The compressor will be fully
loaded (both unloader coils de-energized). Note suc-
tion pressure.
2 Unplug both unloader coils.
3 Using cable included in the test kit (Carrier Transicold
part number 07-50006-00), energize the front unload-
er (UL1). Note discharge and suction pressures. A
rise of approximately 3 psig (0.2 bar) will be noted on
the suction pressure gauge. Discharge pressure
should drop approximately 5 to 15 psig (0.4 to 1.0
bar).
4 Disconnect UL1 and note pressures. Suction pres-
sure should drop and discharge pressure should rise
by same amount as in step 3 above.
5 Repeat steps 3 & 4 for the rear unloader (UL2). At the
end of the test, reconnect both unloaders.
If pressures do not change as indicated, check
the unloader coil resistance (refer to Section
2.12). Replace if coil is open or shorted. If either
unloader coil energizes and the suction and dis-
charge pressures do not change, the unloader
assembly must be checked.
b. Unloader Coil Replacement
The coil may be removed while the compressor
is under pressure.
1. Disconnect leads and lift coil (see Figure 8−24) off en-
closing tube.
2. Verify replacement coil is the correct type, voltage
and frequency.
3. Place new coil over enclosing tube. With wiring facing
in the desired direction, ensure roll pin is fitted in one
of the detents in the bottom of the coil mounting. Coll
is to snap into place with bottom in contact with the
enclosing tube nut. Connect wiring.
4. Check operation, refer to preceding step a.
13
12
11
10
9
8
1. Coil Assembly
2. Pin, Roll
3. Enclosing Tube Nut
4. Enclosing Tube
5. Bolts, Valve Body (3)
6. Washers (3)
7. Piston
Figure 8−24 Unloader Coil
8−25
NOTE
NOTE
1
2
3
4
5
6
7
8. Gasket
9. Valve Body
10. "O" Ring
11. Plunger
12. Plunger Spring
13 Installation/Removal
Tool
62-11389