15
In addition to the refrigeration system, check all condenser water lines, humidifi er make-up lines,
condensate lines, condensate pumps, chilled water lines, centrifugal pumps and fl uid coolers as
applicable.
When handling or recovering refrigerant it is not permissible to release refrigerant into the atmo-
sphere. Many leak-test methods recommended in the past are no longer possible. Current stan-
dard practices must be used.
Pressurize system circuit to 150 PSIG (1034 kPa) by using dry nitrogen with a trace of refrigerant.
Check the entire system for leaks with suitable leak fi nder (per local code) including but limited to
all braze joints, caps, fi ttings and fl are nuts on both fi eld and factory furnished components. After
completion of leak testing, release test pressure and pull a vacuum on the system.
NOTE: Tightening of fi ttings and valves is the responsibility of the installing contractor
2.7 Evacuation
Evacuate the refrigerant lines, condenser coil and evaporator coil to 250 microns or lower (a micron
gauge and 2-stage vacuum pump are required). Valve off and turn off the vacuum pump and wait
for at least fi fteen minutes to make sure the micron gauge reading does not go back up above 700
microns. If it does, re-start the vacuum pump and evacuate until the system reaches 250 microns.
If the system still does not hold the pressure below 700 microns the system needs to be rechecked
for leaks.
After the system has been satisfactorily evacuated the unit(s) can be charged with refrigerant. Con-
nect the pressure gauge manifold set to the high and low ports near the compressor, connect the
charging line to the refrigerant tank and set it for liquid feed. Open the refrigerant tank valve and
purge the line at the manifold, then open the high side valve on the manifold only, and allow the
refrigerant to fl ow until the system pressure equalizes. At this point the system will have 75 to 80%
of the total refrigerant charge. Start the blower and then the compressor checking the operating
pressure and temperatures.
WARNING: DO NOT APPLY POWER TO THE COMPRESSOR WHEN IN A VACUUM
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