Evacuate System (A/C-2).

TM 55-1905-223-24-17

(11) Once the charge has been removed, the system can be opened for maintenance.

b. Evacuate System (A/C-2).

CAUTION

Make sure the oil level in the compressor is at the half-way point in the observation

window before evacuating.

(1) Use a refrigeration vacuum pump and a portable gauge manifold to evacuate the system.

(2) Make sure both handwheels on the gauge manifold are closed fully clockwise.

(3) Connect combination (suction) hoseline from manifold to suction service valve on

compressor. Connect high pressure hoseline from the manifold to the discharge service

valve on the compressor. Open both service valves by turning stems three or four turns

clockwise.

(4) Connect the common (middle) hoseline from the manifold to the suction connection of a

vacuum pump.

(5) Make sure all hoseline connections are secure.

(6) Start and run the vacuum pump. Slowly open both gauge port handwheels on the manifold

counterclockwise.

NOTE

It may be necessary to restrict the vacuum pump suction pressure by means of the

gauge port handwheels to avoid overloading the vacuum pump motor.

Evacuation of system may be a slow process.

(7) Continue running vacuum pump until a reading of 18 inches vacuum is obtained on both

gauges (or to the limit of the vacuum pump's ability).

(8) When evacuation is complete, close both gauge port handwheels on the manifold fully

clockwise. Stop the vacuum pump.

(9) Leave the gauge manifold connected and wait 15 minutes. Check pressure readings.

(10) If the vacuum has been lost, or if you were unable to obtain a vacuum initially, there is

loose hoseline connection or a leak in the system. Check hoseline connections.

(11)

Test for leak (Item 10, Table 3-1) and repeat the above evacuation procedure.

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