SERVICING
48
1. Never open a system that is under vacuum. Air and
moisture will be drawn in.
2. Plug or cap all openings.
3. Remove all burrs and clean the brazing surfaces of the
tubing with sand cloth or paper. Brazing materials do
not ow well on oxidized or oily surfaces.
4. Clean the inside of all new tubing to remove oils and
pipe chips.
5. When brazing, sweep the tubing with dry nitrogen to
prevent the formation of oxides on the inside surfaces.
6. Complete any repair by replacing the liquid line drier in
the system, evacuate and charge.
BRAZING MATERIALS
IMPORTANT NOTE:
- Sil-Fos used without ux
(alloy of 15% silver, 80% copper, and 5% phosphorous).
Recommended heat 1400°F.
- Silver Solder used without
a ux (alloy of 30% silver, 38% copper, 32% zinc).
Recommended heat - 1200°F.
Leak test the system using dry nitrogen and soapy
water to identify leaks. If you prefer to use an electronic
leak detector, charge the system to 10 PSIG with the
appropriate system refrigerant (see Serial Data Plate
for refrigerant identication). Do not use an alternative
refrigerant. Using dry nitrogen nish charging the system
to 450 PSIG. Apply the leak detector to all suspect areas.
When leaks are discovered, repair the leaks, and repeat
the pressure test. If leaks have been eliminated proceed to
system evacuation.
Condensing unit liquid and suction valves are closed to
contain the charge within the unit. The unit is shipped with
the valve stems closed and caps installed. Do not open
valves until the system is evacuated.
The Deep Vacuum Method requires a vacuum pump
rated for 500 microns or less. This method is an eective
and ecient way of assuring the system is free of non-
condensable air and moisture. As an alternative, the Triple
Evacuation Method is detailed in the Service Manual for
this product model.
It is recommended to remove the Schrader Cores from the
service valves using a core-removal tool to expedite the
evacuation procedure.
1. Connect the vacuum pump, micron gauge, and
vacuum rated hoses to both service valves.
Evacuation must use both service valves to eliminate
system mechanical seals.
2. Evacuate the system to less than 500 microns.
3. Isolate the pump from the system and hold vacuum
for 10 minutes (minimum). Typically, pressure will rise
slowly during this period. If the pressure rises to less
than 1000 microns and remains steady, the system is
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