Thermo King UT-1200, Manual

Page: 136 / 169

Refrigeration Service Procedures
136
2. Remove the feeler bulb from the suction line
clamp. Note the position of the feeler bulb on
the suction line.
3. Unsolder the equalizer line from the
expansion valve.
4. Unsolder the inlet liquid line and the line to
the distributor from the expansion valve.
5. Remove the expansion valve mounting bolt
and remove the expansion valve from the unit.
Installation
1. Install and bolt the expansion valve assembly
in the unit.
2. Solder (95-5 Solder) the inlet liquid line and
the distributor to the expansion valve.
3. Solder (95-5 Solder) the equalizer line to the
expansion valve.
4. Clean the suction line to a bright polished
condition. Install the feeler bulb clamps and
the feeler bulb on the side of the suction line
in its former position. The feeler bulb must
make good contact with the suction line or the
operation will be faulty. Wrap with insulating
tape.
5. Pressurize the low side and check for leaks.
6. If no leaks are found, replace the liquid line
drier then evacuate the low side.
7. Open the refrigeration valves and place the
unit in operation.
8. Test the unit to see that the expansion valve is
properly installed.
Heat Exchanger Replacement
NOTE: It unlikely that the heat exchanger is
defective. Carefully review your refrigeration
system diagnosis to eliminate all other system
components before proceeding. This
replacement procedure should only be attempted
by qualified technicians.
Removal
1. Pump down the low side and equalize the
pressure to slightly positive. Make sure to
front seat the suction service valve to isolate
the low side and use the suction access port to
access the low side.
2. Remove the mounting hardware that holds the
heat exchanger on the evaporator.
3. Unsolder the suction and liquid lines.
4. Remove the heat exchanger assembly from the
evaporator.
5. Lift the heat exchanger assembly out of the
evaporator housing.
Installation
1. Clean the tubes for soldering.
2. Place the heat exchanger assembly in the
evaporator housing and install the mounting
hardware loosely.
3. Solder the refrigeration lines connections.
4. Tighten the mounting hardware.
5. Pressurize the low side and test for leaks. If no
leaks are found, evacuate the low side.
6. Open the refrigeration valves and place the
unit in operation. Check the refrigerant charge
and add refrigerant as required.
1. Suction Line
2. Capillary Bulb
3. End View
Figure 205: Location of Expansion Valve Bulb
1. Top View
Figure 206: Completely Wrap Bulb with Tape