13
Front seated.
2) Connect the low pressure gauge to the 3
way service valve access port..
3) Connect the middle hose of the gauge
manifold (usually yellow) to the vacuum
pump.
4) Fully open the handle for the low pressure
gauge..
5) Start the vacuum pump and operate
according to manufacture spec's.
6) Perform an evacuation for a minimum of 30
minutes and check that the low pressure
(compound) gauge indicates a vacuum of
29.9 in/hg (500 microns) A vacuum gauge
should be used if available. If the proper
vacuum cannot be achieved the vacuum
pump should be run for an additional 20
minutes. If after the additional 20 minutes
the vacuum still cannot be achieved the is a
leak in the system and must be located and
repaired. follow the leak checking procedure
as mentioned before. If the vacuum is
achieved, close the low pressure gauge
handle off and shut the vacuum pump off.
Recheck the reading after 10 minutes, the
vacuum may change slightly, this is normal.
7) The system is now dry and free of
contaminates, refrigerant pressure should
now be added to the system from a source
other than the system before opening the 2
way and 3 way valves for system operation.
8) The 2 way and 3 way valve can now be
opened for the system operation
2. Air purging by refrigerant
Procedure:
1). Confirm that both the 2-way and 3-way
valves are set to the closed position.
2). With a container of refrigerant and a gauge
manifold set, connect the low pressure gauge
hose to the 3 way valve service port and a
charging cylinder to the service port of the
3-way valve.
3). Open the valve on the refrigerant container
and the low pressure gauge to allow the
refrigerant to enter the system, next loosen the
flare connection on the 2 way valve line to purge
the air and contaminants from the system for 30
to 50 seconds, then retighten the connection.
4). Next allow the pressure from the refrigerant
to reach 100 psi and then close the low
pressure gauge and the refrigerant container
and check the 2 way and 3 way valve line
connections for leaks with liquid soap or
electronic leak detector.
5). After the system has been check for leaks
the pressure should be adjusted to about 25 to
50 psi.
6). You can now disconnect the gauge manifold
and refrigerant container from the system and
open the 2 way and 3 way valves for system
operation
7). Mount the valve stems nuts and the service
port cap.
Be sure to use a torque wrench to tighten the
service port cap to a torque 18N·m(13.27 ft.lbs).
Be sure to check the gas leakage.
6.5 Adding the refrigerant after running the
system for many years
Procedure
