Midea PH Series Manual page 28

9.2.3 Hermetic compressor replacement.
The following procedure applies when replacing components in the sealed refrigeration circuit or
repairing refrigerant leaks. (Include Compressor, condenser, evaporator, capillary tube, refrigerant
leaks, etc.)
1. Recover the refrigerant from the system at the process tube located on the high side of the system
by installing a line tap on the process tube. Apply gauge from process tube to EPA approved
gauges from process tube to EPA approved recovery system. Recover CFCs in system to at least
5%.
2. Cut the process tube below pinch off on the suction side of the compressor.
3. Connect the line from the nitrogen tank to the suction process tube.
4. Drift dry nitrogen through the system and unsolder the more distant connection first. (Filter drier,
high side process tube, etc.)
5. Replace inoperative component, and always install a new filter drier. Drift dry nitrogen through the
system when making these connections.
6. Pressurize system to 30 PSIG with proper refrigerant and boost refrigerant pressure to 150 PSIG
with dry nitrogen.
7. Leak test complete system with electric halogen leak detector, correcting any leaks found.
8. Reduce the system to zero gauge pressure.
9. Connect vacuum pump to high side and low side of system with deep vacuum hoses, or copper
tubing. (Do not use regular hoses.)
10. Evacuate system to maximum absolute holding pressure of 200 microns or less. NOTE: This
process can be speeded up by use of heat lamps, or by breaking the vacuum with refrigerant or
dry nitrogen at 5,000 microns. Pressure system to 5 PSIG and leave in system a minimum of 10
minutes. Recover refrigerant, and proceed with evacuation of a pressure of 200 microns or a
minimum of 10%.
11. Break vacuum by charging system from the high side with the correct amount of refrigerant
specified. This will prevent boiling the oil out of the crankcase.
NOTE: If the entire charge will not enter the high side, allow the remainder to enter the low side in
small increments while operating the unit.
12. Restart unit several times after allowing pressures to stabilize. Pinch off process tubes,
cut and solder the ends. Remove pinch off tool, and leak check the process tube ends
9.2.4 Special procedure in the case of compressor motor burnout
1. Recover all refrigerant and oil from the system.
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