Figure 4-9 Unloader Solenoid Valve; Checking And Replacing Filter-Drier - Carrier SUPRA 850Mt Operation And Service Manual

2. Verify coil type, voltage and frequency of old and new
coil. This information appears on the coil housing.
3. Place new coil over enclosing tube, retainer and
connect wiring.
c. Replacing solenoid valve internal parts (see
Figure 4-9)
1. Pump down the unit. Frontseat both service valves
to isolate the compressor.
2. Remove coil.
3. Remove enclosing tube collar (item 4, Figure 4-9)
using installation/removal toolsuppliedwith repairkit
(item 3).
4. Check plunger for restriction due to: (a) Corroded or
worn parts; (b) Foreign material lodged in valve; (c)
Bent or dented enclosing tube.
5. Install new parts. Do not overtighten enclosing tube
assembly. Torque to a value of 100 inch pounds
(1.15 mkg).
6. Remove supplied installation/removal tool. Install
coil, voltage plate.
7. Evacuate and dehydrate the compressor. (Refer to
section 4.7)
8. Start unit and check unloader operation (Refer to
section 4.11.a.).
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
13.
1. Coil assembly
2. Installation/removal tool
3. Enclosing tube Collar
4. "O"ring
5. Enclosing tube
6. Plunger spring
7. Plunger assembly

Figure 4-9 Unloader solenoid valve

11.
12.
8. Gasket
9. Valve body
10. Gasket
11. Bolt
12. Gasket, bolt
13. Piston ring
4-14
4.12 CHECKING AND REPLACING
FILTER-DRIER
2 methods
To Check Filter-Drier
- - Check for a restricted or plugged filter-drier
by feeling the liquid line inlet and outlet connec-
tions of the drier cartridge. If the outlet side
feels cooler than the inlet side, then the filter-
drier should be changed.
- - Inspect liquid sightglass humidity indicator.
To Replace Filter-Drier
a. Pump down the unit per section 4.5.
Remove bracket, then replace drier.
b. Check refrigerant level. (Refer to section 4.8.2)
4.13 CHECKING AND REPLACING HIGH
PRESSURE CUTOUT SWITCH
4.13.1 Replacing high pressure switch
a. Pump down theunit (Refer to section 4.5). Frontseat
both suction and discharge service valves to isolate
compressor (HP) or discharge and receiver valve
(BP).
b. Slowly release compressor pressure through the
service valve gauge ports.
c. Disconnect wiring from defective switch. The high
pressure switch is located near the top of the
compressor. Low pressure switch on compressor or
suction line.
d. Install new cutout switch after verifying switch
settings. (Refer to section 4.13.2)
e. Evacuate and dehydrate the compressor. (Refer to
section 4.7)
4.13.2 Checking high pressure switch
WARNING
Do not use a nitrogen cylinder without
a pressure
pressure is approximately 165 kg/cm
(2350 psi). Do not use oxygen in or
near a refrigerant system as an
explosion mayoccur (see Figure 4-10).
regulator. Cylinder
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