Compressor Replacement

Parent topic: Refrigeration Maintenance

Removal

  1. Close the suction service valve and pump down the compressor:

    • R-134a Compressor: Pump down the compressor to -35 kPa, -0.35 bar, 10 in. vacuum.

    • R-23 Compressor: Pump down the compressor to 0 to 21 kPa, 0.0 to 0.2 bar, 0 to 3 psig.

      Caution
    • Equipment Damage
    • Do NOT allow the R-23 scroll compressor to operate for more than 10-20 seconds.

  2. Break the vacuum with nitrogen between 10 and 20 kPa, 0.10 and 0.20 bar, 1 and 3 psig.

    Note If the compressor does not operate, or the compressor is unable to pump the low side down, the refrigerant charge must be reclaimed before service can be performed on the refrigeration system.

  3. Front seat the discharge valve.

      Caution
    • Equipment Damage
    • Any time the discharge valve is front seated, disconnect the unit power source to prevent accidental compressor start-up.

  4. Remove discharge service valve and suction service valve from the compressor.

  5. Disconnect the wire connector for the high pressure cutout switch.

  6. Remove the three-phase electric power connection.

  7. Remove the compressor mounting tray bolts and nuts.

  8. Slide the compressor from the unit.

  9. Keep the compressor ports covered to prevent dust, dirt, etc., from falling into the compressor.

    Note When the compressor is removed from the unit, oil level should be noted or the oil removed from the compressor should be measured so that the same amount of oil can be added before placing the new compressor or repaired compressor in the unit.

Installation

  1. Slide the compressor into the unit. Install mounting bolts, washers and nuts, and tighten.

  2. Bolt the discharge valve to the compressor with a new gasket lightly coated with compressor oil. Bolt the suction service valve to the compressor using a new O-ring coated with compressor oil.

  3. Apply refrigerant locktite to the threads of the high pressure cutout switch. Install the switch and connect the wire connectors.

  4. Connect three-phase electric power to the compressor.

  5. Pressurize the compressor with refrigerant gas:

    • R-134 compressor with R-134a refrigerant.

    • R-23 compressor with R-23 refrigerant.

      Caution
    • Equipment Damage
    • Be sure to add the correct refrigerant to the compressor.

  6. Check for refrigerant leaks around the compressor assembly and gasket connections.

  7. If no leaks are found, recover the refrigerant used for the leak test (see “Refrigerant Recovery” in this chapter). Because this refrigerant gas will contain some air, place it in a contaminated refrigerant bottle to be reclaimed later.

  8. After all pressure is removed from the compressor, connection the evacuation equipment.

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

  10. Back seat the discharge service valve and open the suction service valve fully.

  11. Operate the unit at least thirty minutes and then inspect the oil level in the compressor. Add or remove oil if necessary.

      Caution
    • Equipment Damage
    • Do NOT operate the unit on cooling unless both the R-134a and the R-23 refrigeration systems contain a partial charge of refrigerant.

  12. Check the refrigerant charge and add refrigerant if needed.