Filter Drier Replacement

Parent topic: Refrigeration Maintenance

Removal

  1. 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).

  3. Place the new dehydrator near the unit for immediate installation.

  4. Remove the filter bracket clamping nuts and bolts.

  5. Do one of the following:

    • R-134a System: Using two wrenches, “crack” both filter drier line mountings. Use two wrenches on flare fittings to prevent line damage. Separate the dehydrator line mountings.

    • R-23 System: Unsolder filter drier from liquid line.

    Note Perform the following four procedures as quickly as possible to prevent contamination.

  6. Remove the old dehydrator from the line.

Installation

  1. Remove the sealing caps from the new dehydrator.

  2. Do one of the following:

    • R-134a System: Apply clean compressor oil to dehydrator threads. Assemble new dehydrator to lines. Finger tighten mounting nuts.

    • R-23 System: Clean tubes for soldering. Position filter drier in liquid line. Solder filter drier in liquid line.

    Note To prevent incorrect installation of the dehydrator, the inlet and outlet fittings are different sizes.

  3. Reinstall dehydrator clamping brackets, nut and bolts. Tighten the bolts.

  4. Do one of the following:

    • R-134a System:

    1. Tighten the dehydrator inlet line mounting nut. Open the liquid line service valve on the inlet side of the dehydrator slowly to release a small amount of refrigerant from the receiver tank to purge the air through the filter. Then tighten the outlet nut.

      Note R-134a — When removing or replacing the o-ring nuts on the dehydrator, always hold the body of the dehydrator near the flange fittings to prevent twisting the tubing when the nuts are being loosened or tightened.

    2. Back seat (open) the liquid line service valve on the inlet side of the dehydrator.

    3. Test refrigeration system and check for leaks (Refer to Leak Testing Refrigeration System). Repair leaks if required.

    4. If no leaks are found, place the unit in operation.

    • R-23 System:

    1. Pressurize the refrigeration system and check for leaks (Refer to Leak Testing Refrigeration System). Repair leaks if required.

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

    3. Evacuate the system (Refer to Evacuation and Cleanup of Refrigeration System).

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    4. Recharge the unit with R-23 (Refer to Charging System with Refrigerant).