Expansion Valve Replacement

Do one of the following:

• R-134a System: Close the liquid line service valve and pump down the low side. Open the outlet valve slightly to equalize the pressure between 10 and 20 kPa, 0.10 and 0.20 bar, 1 and 3 psig.

• R-23 System: Recover the refrigerant charge from the unit (do NOT vent refrigerant to the atmosphere).

Remove insulating tape and encamp feeler bulb from the suction line. Note the position of the feeler bulb on the side of the suction line.

Remove insulating tape from expansion valve outlet line.

Heat and unsolder the equalizer line from expansion valve.

Heat and unsolder the liquid line inlet and outlet connections to expansion valve.

Remove expansion valve from unit.

Clean the liquid lines and equalizer lines for soldering.

Place new expansion valve in position in liquid line.

Solder liquid line inlet and outlet line connections to valve.

Solder equalizer line to expansion valve.

Clean the suction line to a bright polished condition. Install the feeler bulb of new power head in the feeler bulb clamp on the suction line. Locate bulb on the suction line in former position. The feeler bulb must make good contact with the suction line or operation will be faulty. Cover with insulating tape.

Do one of the following:

• R-134a System:

1. Open the liquid line service valve and pressurize the low side. Test for leaks (see “Refrigerant Leak Test Procedure” in this chapter).

2. If no leaks are found, recover the leak test gas (see “Refrigerant Recovery” in this chapter).

3. Evacuate the low side (see “Evacuation and Cleanup of the Refrigeration System” in this chapter).

4. Cover expansion valve outlet line with insulating tape.

5. Open the liquid line service valve and place the unit in operation.

6. Operate the unit and note the suction pressure and container temperature to see that the expansion valve is properly installed and that the feeler bulb is properly located.

• R-23 System:

1. Pressurize the system with R-23 and test for leaks (see “Refrigerant Leak Test Procedure” in this chapter).

2. If no leaks are found, recover the leak test gas (see “Refrigerant Recovery” in this chapter).

3. Evacuate the system (see “Evacuation and Cleanup of the Refrigeration System” in this chapter).

4. Cover expansion valve outlet line with insulating tape.

5. Recharge the unit with R-23 refrigerant and check the compressor oil level. Add oil if necessary.

6. Operate the unit and note the suction pressure and container temperature to see that the expansion valve is properly installed and that the feeler bulb is properly located.