TM 9-4120-401-14
Evacuate
This task covers:
INITIAL SETUP
Equipment Condition
Tools
Refrigeration Unit Service Tool Kit
Vacuum Pump
Use disconnect switch (NOT POWER
CABLE) to disconnect power to unit.
Damage to cable connector pins will
result if cable is used.
Disconnect power at power source.
Evacuate.
(1) Check that new refrigerant desiccant dehydrator was installed. If not, install one. (See paragraph 5-22.)
(2) Check that service manifold charge valve is closed.
(3) Check that unit HIGH and LOW PRESSURE CHARGING VALVES are open
(4) Connect the vacuum hose to vacuum pump.
(5) Start vacuum pump.
(6) Open service manifold high pressure gauge, compound gauge, and vacuum valves.
(7) Run vacuum pump until at least 29 inches of mercury is measured on compound gauge.
NOTE
Inability to reach and hold 29 inches of mercury may indicate either a leak or a
problem with the vacuum pump.
( 8 ) Continue running vacuum pump for one more hour, while observing the gauge. If gauge needle
moves back and forth, you have a leak which must be located and corrected. (See paragraph 5-16.)
(9) Close unit HIGH and LOW PRESSURE CHARGING VALVES.
(10)
Close service manifold high pressure gauge, compound gauge, and vacuum valves.
(11)
Stop vacuum pump.
5-43