Thermo King SB-190 30, Manual

Page: 88 / 119

Refrigeration Service Operations (Rev. 12/03)
78
HIGH PRESSURE RELIEF VALVE
Removal
1. Recover the refrigerant charge.
2. Unscrew and remove the high pressure relief valve.
Installation
1. Apply a refrigerant oil to the O-ring of the high pres-
sure relief valve.
2. Install and tighten the high pressure relief valve.
3. Pressurize the refrigeration system and test for leaks. If
no leaks are found, evacuate the system.
4. Recharge the unit with the proper refrigerant and check
the compressor oil.
DISCHARGE PRESSURE TRANSDUCER
(OPTIONAL)
Removal
1. Recover the refrigerant charge.
2. Disconnect the wires and remove the discharge pres-
sure transducer.
Installation
1. Apply a refrigerant Loctite to the threads of the dis-
charge pressure transducer.
2. Install and tighten the discharge pressure transducer
and reconnect the wires.
3. Pressurize the refrigeration system and test for leaks. If
no leaks are found, evacuate the system.
4. Recharge the unit with the proper refrigerant and check
the compressor oil.
SUCTION PRESSURE TRANSDUCER
(OPTIONAL)
Removal
1. Pump down the low side and equalize pressure to
slightly positive.
2. Disconnect the wires and remove the suction pressure
transducer.
Installation
1. Apply a refrigerant Loctite to the threads of the suction
pressure transducer.
2. Install and tighten the suction pressure transducer and
reconnect the wires.
3. Pressurize the low side and check for leaks. If no leaks
are found, evacuate the low side.
4. Open the refrigeration valves and place the unit in oper-
ation.
ELECTRONIC THROTTLING VALVE
(OPTIONAL)
Removal
1. Attach a gauge manifold to the compressor.
2. Pump down the low side and equalize the pressure to
slightly positive.
3. Remove the evaporator access panels.
4. Remove the clip and disconnect the ETV harness con-
nector from the stepper motor.
5. Unscrew the large nut that attaches the stepper motor
and piston assembly to the valve body. The torque on
the nut is approximately 100 ft-lb (136 N•m). Hold the
valve body with backup wrench to prevent damage to
the refrigeration tubing.