Evacuate System (A/C-1 and 3).

TM 55-1905-223-24-17

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.

(8) 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).

(9) When evacuation is complete, close both gauge port handwheels on the manifold fully clockwise. Stop

the vacuum pump.

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

(11) 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.

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

(13) Once you are able to maintain a vacuum reading on the gauges, disconnect the common hoseline from

the vacuum pump and connect it to a container of refrigerant

(14) Loosen the common hoseline connection at the gauge manifold momentarily, crack the refrigerant

container valve to purge the hose, and retighten the hose connection.

(15) Crack the valve on the refrigerant container. Crack the valves (handwheels) on the gauge manifold

until the system pressure rises to 2 psig. Close the valve on the refrigerant container and both

handwheels of the manifold.

(16) Disconnect the common hoseline from the refrigerant container and reconnect it to the suction

connection on the vacuum pump.

(17) Start the vacuum pump, slowly open both handwheels on the manifold, and again evacuate the system

to 18 inches vacuum (or to limit of pump's ability).

(18) Close both handwheels on the manifold, stop the vacuum pump, and wait 15 minutes to see that a

vacuum is held.

(19) When a vacuum is maintained, disconnect the common hoseline from the vacuum pump.

(20) The system is now ready to recharge.

c. Recharge System (A/C-1 and 3).

(1)

Determine the weight of refrigerant charge required from the data plate on the unit.

(2)

Use the scale from the refrigeration tool kit and weigh the refrigerant container before charging. Make

sure the container is holding more refrigerant (weight) than required for the charge.

(3)

With the system evacuated and the portable gauge manifold still hooked up to the unit, connect the

common hoseline of the manifold to the refrigerant container.

Change 2 3-13