(f) Connect a nitrogen regulator and cylinder of dry nitrogen to the manifold.
(g) Open the charging manifold valves and the nitrogen cylinder and regulator valve. Allow system
pressure to build up until gages read 350 psig (24.7 kg/cm2 ).
(h) Perform leak tests, then recover and purge the system, in accordance with steps b. and c. of this
paragraph before performing maintenance, or before evacuating and charging the system, as
(5) Always perform a final leak test after performing any repair or replacement of components before the air
conditioner is reassembled and the refrigeration system is evacuated and charged.
Refrigerant/nitrogen mixture will damage recovery unit. DO NOT attempt to
recover refrigerant/nitrogen combination used for leak test. Discharge this test
mixture to open air.
e. Evacuating the System .
(1) Attach vacuum pump to manifold.
(2) Start vacuum pump.
(3) Open high pressure and low pressure service valves.
(4) Run the vacuum pump for at least two hours. If the refrigerant system is larger or has been opened for a
long period of time, the vacuum pump must be run longer as required by maintenance technician.
(5) Refer to amount of oil removed during refrigerant recovery and add an equal amount of clean new oil into
the system by siphoning method.
(6) Close high pressure and low pressure service valves.
(7) Disconnect vacuum pump from manifold.
(8) Stop v cuum pump.