26
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Center port manifold hose before hand shut-off
valve to charging cylinder.
•
Center port manifold hose after hand shut-off valve
to vacuum pump.
Evacuating System
WARNING: R-134A SYSTEMS ARE
PARTICULARLY SUSCEPTIBLE TO
MOISTURE CONTAMINATION WHICH
CAN ONLY BE PREVENTED BY
EVACUATING THE SYSTEM FOR A
MINIMUM OF 30 MINUTES TO ATTAIN A
MINIMUM 29.9 INCH (500 MICRON OR
LOWER) VACUUM.
To achieve the required levels of evacuation, a properly
maintained two stage vacuum pump in good condition is
required. It is absolutely essential to maintain your
vacuum pump according to the manufacturer’s
instructions including required oil changes at the
recommended intervals. Vacuum pump oil should always
be changed after evacuating a contaminated system.
Vacuum pump performance should be checked
periodically with a micron gauge.
1.
Make certain that charging cylinder valve, hand
shut-off valve, and manifold gauge valves are closed.
2.
Start vacuum pump.
3.
Open hand shut-off valve and slowly open both
manifold valves, turning counterclockwise, for two
full rotations.
CAUTION: If high vacuum equipment is used, just
crack both manifold valves for a few
minutes and then open slowly for the
two full turns counterclockwise. This will
prevent the compressor oil from
foaming and being drawn into the
vacuum pump.
4.
Operate the vacuum pump for a minimum of 30
minutes to a minimum of 29.9” (500 micron) vacuum.
5.
Close hand shut-off valve to vacuum pump. Watch
compound gauge for several minutes. If reading rises,
there is a leak in the system, go to step 6. If no leak
is indicated, stop vacuum pump. System is now
ready for charging.
6.
If a leak is indicated, stop vacuum pump and
introduce a small charge of refrigerant into system
by cracking valve on bottom of charging cylinder
until system is pressurized to 40 or 50 lbs psig.
7.
Leak test low-side. Close compound gauge.
Run compressor for a few minutes and leak test
high side.
When leak is found, recapture refrigerant using EPA
approved recovery system Repair and go back
to step 1.
Charging the System
CAUTION: Check the serial plate for the correct
refrigerant type. It is extremely
important to verify the type of
refrigerant in the system before
starting any sealed system repairs.
CAUTION: After charging the system with liquid be
certain to wait at least 5 minutes before
starting the compressor to give the
refrigerant a chance to disperse
throughout the system. Otherwise the
compressor could be damaged by
attempting to pump excessive
quantities of liquid.
Preparing The Charging Cylinder:
1.
Make certain that hand shut-off valve to vacuum
pump is closed.
2.
Close high-side manifold gauge valve.
3.
Set charging cylinder scale to pressure indicated
on cylinder pressure gauge.
4.
Observe refrigerant level in sight glass. Subtract
amount to be charged into system and note shut off
point.
5.
Open charging cylinder valve slowly and allow proper
charge to enter system.
6.
As soon as refrigerant in sight glass has gone down
to predetermined level, close charging cylinder valve.
WARNING: DISCONNECT THE CHARGING
CYLINDER HEATER AT THIS TIME TO
PREVENT THE CYLINDER PRESSURE
FROM EXCEEDING ITS MAXIMUM
LIMITS.
7.
Allow system to sit for five minutes.
8.
Turn on freezer’s compressor. and allow it to run
for a few minutes and monitor system pressures.
