b. Refrigerant Recovery.
(1) Connect recovery unit to manifold charging valve.
(2) Operate recovery unit in accordance with recovery unit operator's manual.
(3) Record amount of oil collected in recovery unit after completing refrigerant recovery.
This oil quantity
indicates the amount of oil to be replaced in the refrigerant system.
(4) Remove the recovery unit from manifold charging valve.
(1) Remove safety cap from nitrogen cylinder and install regulator onto nitrogen cylinder.
(2) Connect regulator and nitrogen cylinder to manifold.
(3) Disconnect manifold hose from low pressure service valve.
(4) Open nitrogen cylinder valve and adjust regulator so that 1-2 psig of nitrogen flows through the system.
(5) Allow nitrogen to sweep through the system at a rate of not less than 1-2 psig for not less than 5 minutes
before beginning any brazing or debrazing operations. Allow nitrogen to continue to flow through the system at the same
rate until all brazing or debrazing operations are complete.
(6) When brazing operations are complete, close valve on nitrogen cylinder.
(7) Disconnect manifold hose from nitrogen cylinder and regulator.
(8) Remove regulator from nitrogen cylinder and install safety cap onto cylinder.
d. Leak Testing the System .
(1) Recover refrigerant from system per step b.
(2) When to Test. The entire repaired area should be thoroughly leak tested after repair or replacement of any
component, before it is recharged with refrigerant 22. Leak testing is also the method for troubleshooting when a system
has lost all or part of its refrigerant charge through an undetermined cause.