Midea PD Series Manual page 32

8. Accurate refrigerant charge measuring device such as:
a. Balance Scales - 1/2 oz. accuracy
b. Charging Board - 1/2 oz. accuracy
9. High Pressure Gauge - (0 - 400 lbs.)
10. Low Pressure Gauge - (30 - 150 lbs.)
11. Vacuum Gauge - (0 - 1000 microns)
9.2.2 Equipment must be capable of:
1. Recovery CFC's as low as 5%.
2. Evacuation from both the high side and low side of the system simultaneously.
3. Introducing refrigerant charge into high side of the system.
4. Accurately weighing the refrigerant charge actually introduced into the system.
5. Facilities for flowing nitrogen through refrigeration tubing during all brazing processes.
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
30