(h) If a leak was not found and Refrigerant-22 was used to pressurize the system see charging
(2) To pressurize a system that has been discharged and purged, for leak testing with an electronic
(a) Remove the caps from the high and low pressure charging valves.
(b) Connect the hoses from a charging manifold to the charging valves.
(c) Connect a drum of Refrigerant-22 to the center hose connection of the service manifold.
Connect the Refrigerant-22 drum so that only gas will be used for pressurization.
(d) Open both unit charging valves and the charging manifold valves.
(e) Open the refrigerant drum valve slightly and adjust as necessary to prevent formation of frost; and,
allow system pressure to build up until the gages read 40-50 psi (2.8 -3.5 kg/cm2).
(f) Close the charging manifold valves and the refrigerant drum valve.
(g) Remove the Refrigerant-22 drum from the center hose connection.
(h) Connect a cylinder of dry nitrogen to the center hose connection.
(i) Open the charging manifold valves and the nitrogen cylinder valve; allow system pressure to build
up until gages read 350 psi (24.7 kg/cm2).
(j) perform leak tests, then discharge and purge the system, in accordance with paragraphs 5-9 and
5-10 before performing maintenance, or before evacuating and charging the system, as appropriate.
(3) Final Leak Testing. 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.
The refrigeration system must be evacuated to remove all moisture before it is charged with Refrigerant-22.
Check that system was leak tested and has NO LEAKS.
Check that new filter-drier was instaIled. If not, install one.
Check that both charging valves and charging manifold valves are closed.
Attach hose assemblies to charging valves and charging manifold valves.
Attach center hose assembly to vacuum pump.
Start vacuum pump.
Open charging manifold valves.
Open both unit charging valves.
Run the vacuum pump until at least 29 inches of mercury, measured on the gage, is reached.