TM9-4120-401-14
PURGING THE REFRIGERANT SYSTEM.
Purge
This task covers:
INITIAL SETUP
E q u i p m e n t Condition
Tools
Refrigeration Unit Service Tool Kit
Appendix B, item 1
Goggles
Use disconnect switch (NOT POWER
Appendix B, item 2
CABLE) to disconnect power to unit.
Damage to cable connector pins will
Nitrogen Regulator
result if cable is used.
Appendix B, item 7
Disconnect power at power source.
Install service manifold (para 5-11).
Nitrogen
Appendix E, item 8
Discharge refrigerant system (para 5-12).
The pressure in a nitrogen cylinder can exceed 2000 psi. A nitrogen pressure
regulator should be used at all times to avoid personal injury.
Nitrogen is an inert gas that can cause suffocation and must be discharged in a
well ventilated area.
Purge.
(1) Connect the charge hose to a nitrogen regulator and dry nitrogen cylinder.
(2) Disconnect the compound gauge hose from the service manifold.
(3) Be sure the compound gauge and vacuum valves are closed.
(4) Be sure that HIGH and LOW PRESSURE CHARGING VALVES are open.
(5) Open the pressure gauge and charge valves.
(6) Open the nitrogen cylinder valve and adjust the regulator so that approximately 1-2 cfm (0.028 -0.057
m3/minute) of nitrogen flows through the system.
(7) Check discharge from the compound gauge hose attached to the LOW PRESSURE CHARGING
VALVE to be sure that no oil is being forced out of the system.
(8) When purging is completed, close nitrogen cylinder valve.
(9) Disconnect the charge hose from nitrogen regulator.
(10) Connect the compound gauge hose to service manifold.
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