Thermo King 914 724, Manual

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Refrigeration Service Operations (Rev. 1/99)
61
Installation
1. Place the accumulator in the unit and tighten the
mounting bolts.
2. Solder the inlet and outlet suction lines to the accumu-
lator.
3. Pressurize the low side and test for refrigerant leaks. If
no leaks are found, evacuate the low side.
4. Open the refrigeration valves and place the unit in oper-
ation. Check the refrigerant charge and compressor oil
and add as required.
THREE-WAY VALVE REPAIR
In most cases, the three-way valve can be repaired in the
unit.
Disassembly
1. Remove the refrigerant charge.
2. Clean the exterior surface of the valve.
3. Remove the 1/4 in. (6 mm) copper line from the three-
way valve to the pilot solenoid.
4. Loosen the four Allen head screws (DO NOT
REMOVE); use Tool P/N 204-424 to break the gasket
at each side of the center section.
CAUTION: Do not force the tool into the brass
or against the bolts.
5. Remove the four bolts from the valve.
6. Remove the top cap and spring.
7. Remove the spring clip. Observe the slot in the piston
and slide the piston off the stem.
8. Remove the seat and stem assembly.
9. Inspect the following parts for wear or damage:
a. Bottom cap, sealing and support area.
b. Seat, sealing surface.
c. Top cap, sealing and support area.
Remove the screen. If any particles drop from the
screen into the discharge line, the discharge line must
be removed at the compressor.
NOTE: The valve body cannot be reconditioned. Seat
positions change and improper sealing will result.
Assembly
After cleaning and inspecting all parts, reassemble the
valve.
1. Place the screen in the bottom cap.
2. Place a new stem in the bottom cap.
3. Install new gaskets on both sides of the seat. Dip the
gaskets in compressor oil before installing.
4. Install the piston on the stem and attach with a spring
clip.
5. Install a new O-ring on the piston, then place the Teflon
seal over the O-ring.
NOTE: The Teflon seal will stretch when it is
installed. To prevent this stretch from becoming per-
manent (and possibly causing a malfunction), the top
cap must be installed immediately.
6. Install the spring and top cap.
7. Line up the passageways in the top cap and the seat.
Failure to line up the holes will result in improper oper-
ation of the three-way valve.
8. Install the bolts and tighten them in a rotating sequence.
9. Install the pilot solenoid line and pressurize the system
with refrigerant to check for leaks.
10. If there are no leaks, evacuate the system and recharge
with refrigeration.
11. Run the unit to check for proper three-way valve
operation.