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SERVICING
Copper to Copper Joints - Sil-Fos used without flux (alloy
of 15% silver, 80% copper, and 5% phosphorous). Recom-
mended heat 1400°F.
Copper to Steel Joints - Silver Solder used without a flux
(alloy of 30% silver, 38% copper, 32% zinc). Recommended
heat - 1200°F.
LEAK TESTING (NITROGEN OR NITROGEN-TRACED)
To avoid the risk of fire or explosion, never use oxygen,
high pressure air or flammable gases for leak testing of a
refrigeration system.
To avoid possible explosion, the line from the nitrogen
cylinder must include a pressure regulator and a pressure
relief valve. The pressure relief valve must be set to open at
no more than 450 psig.
LEAK TESTING
Leak test the system using dry nitrogen and soapy water to
identify leaks. If you prefer to use an electronic leak de-
tector, charge the system to 10 PSIG with the appropriate
system refrigerant (see Serial Data Plate for refrigerant
identification). Do not use an alternative refrigerant. Using
dry nitrogen finish 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.
STANDING PRESSURE TEST
Using dry nitrogen, pressurize the system to 450 PSIG.
Allow the pressure to stabilize and hold for 15 minutes (min-
imum). If the pressure does not drop below 450 PSIG the
system is considered leak free. Proceed to system evacu-
ation using the Deep Vacuum Method. If after 15 minutes
the pressure drops below 450 PSIG follow the procedure
outlined below to identify system leaks. Repeat the Stand-
ing Pressure Test.
SYSTEM EVACUATION
REFRIGERANT UNDER PRESSURE!
Failure to follow proper procedures may cause property
damage, personal injury or death.
WARNING
WARNING
WARNING
IMPORTANT NOTE: Because of the potential damage to
compressors, do not allow suction pressure at service valve
to drop below 5 PSIG when pumping unit system down for
repair. Outdoor section, depending on line set length and
amount of charge in system, may not be able to hold the
entire system charge.
This is the most important part of the entire service proce-
dure. The life and efficiency of the equipment is dependent
upon the thoroughness exercised by the serviceman when
evacuating air (non-condensables) and moisture from the
system.
Air in a system causes high condensing temperature and
pressure, resulting in increased power input and reduced
performance.
Moisture chemically reacts with the refrigerant oil to form
corrosive acids. These acids attack motor windings and
parts, causing breakdown.
The equipment required to thoroughly evacuate the system
is a vacuum pump, capable of producing a vacuum equiva-
lent to 500 microns absolute and a micron gauge to give a
true reading of the vacuum in the system
NOTE: Never use the system compressor as a vacuum
pump or run when under a high vacuum. Motor damage
could occur.
Condensing unit liquid and suction valves are closed to con-
tain 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.
DEEP VACUUM METHOD
The Deep Vacuum Method requires a vacuum pump rated
for 500 microns or less. This method is an effective and effi-
cient way of assuring the system is free of non-condensable
air and moisture. As an alternative, the Triple Evacuation
Method may be used.
It is recommended to remove the Schrader Cores from the
service valves using a core-removal tool to expedite the
evacuation procedure.
Connect the vacuum pump, micron gauge, and vacuum rat-
ed hoses to both service valves. Evacuation must use both
service valves to eliminate system mechanical seals.
Evacuate the system to less than 500 microns.
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 considered leak-
free; proceed to system charging and startup.
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