Refrigeration Service Operations 11-7
High Pressure Relief Valve
Removal
1. Recover the refrigerant charge.
2. Unscrew and remove the high pressure relief valve.
Installation
1. Apply compressor oil to the O-ring on the high pressure relief valve.
2. Apply a refrigerant locktite to the threads of the high pressure relief valve.
3. Install and tighten the high pressure relief valve.
4. Pressurise the refrigeration system and test for leaks. If no leaks are found, evacuate the system.
5. Recharge the unit with refrigerant and check the compressor oil level.
Dehydrator (Filter-Drier)
Removal
1. Pump down the low side and equalise the pressure to 0 psig, (0 bar g).
2. Disconnect the nuts at the end of the drier. Hold the drier with a back-up wrench on the hex behind the flare fitting.
3. Loosen the mounting hardware and remove the drier.
Installation
1. Apply a thin layer of compressor oil to new O-rings and install in the inlet and outlet nuts.
2. Install the new drier and tighten the mounting bracket screws and nuts.
3. Install and tighten the inlet nut to the receiver tank outlet valve line (inlet end of drier is labelled “IN”). Hold the drier with a
back-up wrench on the hex behind the Flare/ORS (depending on manufacture date of the unit) fitting .
4. Pressurise the system and inspect for leaks. If no leaks are found, evacuate low side (See the correct operation and diagnostic
manual for more information. Place the unit in operation.
5. Back seat the receiver outlet valve, check the refrigerant charge and compressor oil level.
Expansion Valve Assembly
Removal
1. Pump down the low side and equalise pressure to 0 psig, (0 bar g). (Check for Fgas regulations)
2. Remove necessary evaporator access panels.
3. Remove the feeler bulb from the suction line clamp. Note the position of the feeler bulb on the suction line.
4. Disconnect (or unsolder) the equaliser line from the expansion valve.
5. Unsolder the inlet liquid line and the distributor from the expansion valve.
6. Remove the expansion valve mounting bolt. Remove the expansion valve from the unit.
Location of Expansion Valve Bulb
1. End View
2. Side View
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