OPENING THE SYSTEM.

TM 5-4120-364-13

valve. (Refer to figure 4-3).

(2) Close the condenser shutoff valve (outlet) by turning valve stem fully clockwise.

(3) Install a suction pressure gage on the compressor suction service valve as shown in

figure 4-2.

(4) Operate the unit until suction pressure gage registers 5 to 10 inches ( 12.75 to

25.5cm) of mercury vacuum.

(5) Shut off machine and observe pressure gage for a few minutes. If pressure

rebuilds, repeat step (4) until pressure does not rebuild appreciably.

(6) Crack condenser shutoff valve (outlet) until 3 to 4 psig is indicated on the suction

pressure gage.

(7) Close condenser shutoff valve (inlet) by turning valve stem clockwise as far as it

will go.

(8) Remove suction pressure gage from compressor suction service valve.

4-7.

OPENING THE SYSTEM.

Before opening the refrigerant system, the pressure in the system should be known. If the system is

under high pressure. excessive loss of refrigerant will occur. If opened under vacuum, air is drawn into

the system which will cause operating difficulties. If the pressure gage indicates a vacuum after pump-

ing down, open the receiver outlet valve slightly to build 3 to 4 pounds pressure in the system.

4-7.1

DISCHARGING THE REFRIGERANT SYSTEM.

NOTE

In accordance with Environmental Protection Agency

regulations, refrigerants cannot be discharged into the

atmosphere. A refrigerant recovery & recycling unit

must be used whenever discharging the refrigerant

system.

Operation of the recovery/recycling unit must be by

AUTHORIZED PERSONNEL ONLY

Remove service valve caps.

Connect charging manifold service hoses to unit service valves.

Connect and operate a recovery/recycling unit in accordance with the manufacturer's

instructions.

4-6

Change 3