Refrigeration Maintenance and Service Operations
139
12. Verify that all personnel are clear and connect
main power plug to power supply. Start the
unit and check the refrigerant charge. Add
refrigerant as required.
Refrigerant Recovery
When removing any refrigerant from a Thermo
King refrigeration system, use a recovery process
that prevents or absolutely minimizes the
refrigerant that can escape to the atmosphere.
Typical service procedures that require removal of
refrigerant from the unit include:
•
To reduce the refrigerant pressure to a safe
working level when maintenance must be
performed on high-pressure side components.
•
To empty the unit of refrigerant when an
unknown amount of charge is in the system
and a proper charge is required.
•
To empty the unit of contaminated refrigerant
when the system has become contaminated.
NOTE: Always refer to specific recovery
equipment Operator and Service Manuals.
Vapor Recovery
1. Install a gauge manifold set on the unit. Attach
the service line to the recovery machine and
properly purge the lines. Set the recovery
machine for vapor recovery.
2. Keep unit OFF and mid-seat the discharge
service valve.
3. Turn ON the recovery machine and open
(back seat) both gauge manifold and hand
valves.
4. Continue to operate the recovery machine
until unit pressures drop to 0 kPa, 0 bar, 0 psig
pressure.
Liquid Recovery
1. Install a gauge manifold’s low-pressure line to
the service fitting on the suction service valve.
Attach the manifold’s high-pressure line to
receiver tank service port. Attach the service
line to the recovery machine and purge the
lines.
2. Operate the unit and build discharge pressures
to approximately 1380 kPa, 13.80 bar, 200
psig.
3. Close the liquid line service valve and pump
down the low-pressure side of the system.
4. Stop the unit.
5. Set recovery machine for liquid recovery and
turn it ON.
6. Open (back seat) high-pressure valve on
gauge manifold.
7. Operate the recovery machine until the unit
system pressures reach approximately 0 kPa, 0
bar, 0 psig.
Using Pressurized Nitrogen
The improper use of high pressure cylinders can
cause physical damage to components, or
personal injury, or cause stress that would lead to
failure of components.
Safety Precautions
Observe the proper handling of cylinders:
1. Always keep protective cap on cylinder when
not in use.
2. Secure cylinder in proper storage area or
fastened to cart.
3. DO NOT expose to excessive heat or direct
sun light.
4. DO NOT drop, dent, or damage cylinder.
5. Use a pressure regulator and a safety pressure
relief valve as part of the pressure testing
equipment. The safety pressure relief valve
should be of the non-adjustable,
non-tempering type. The valve should bypass
any time the pressure exceeds its setting.
6. Open valve slowly; use regulators and safety
valves that are in good working order.
CAUTION: Use only refrigerant recovery
equipment approved for and dedicated to
R-134a recovery.
Summary of Contents for CRR-40 119
Page 4: ......
Page 16: ...Safety Precautions 16...
Page 18: ...Service Guide 18...
Page 20: ...Model Features 20...
Page 32: ...Specifications 32...
Page 120: ...MP 3000a Controller 120...
Page 160: ...Wiring and Schematic Diagrams Index 160...
Page 161: ...161 MPC2000 Wiring Schematic...
Page 162: ...162 MPC2000 High Voltage Wiring Diagram...
Page 163: ...163 MPC2000 Low Voltage Wiring Diagram...
Page 164: ...164 MPC2000 WCC Wiring Schematic...