SERVICE (cont) - TM-5-4120-393-140237

TM 5-4120-393-14

5-14. Charging Refrigerant System (cont)

NOTE

If power has just been connected to unit, a short (30 minute maximum during very

cold weather) warm up period is required. When compressor reaches a safe

operating temperature, it will come on automatically if the mode selector switch is

in the COOL mode.

16. Turn air conditioner on and operate in the COOL mode with the TEMPerature control thermostat set at a maximum

DECREASE position.

17. If the 9.1 pound (4.13 kg) full charge was obtained, skip steps 18 through 20. If the system pressure equalized prior

to obtaining a full charge of 9.1 pounds (4.13 kg) proceed to step 18.

18. Switch the refrige rant drum to the gas only position.

19. Be sure that the refrigerant drum has been switched to the gas position and open the refrigerant drum valve, the low

(suction) pressure charging manifold valve, and the low (suction) pressure service valve on the air conditioner.

20. Monitor the weight of the refrigerant drum as the air conditioner compressor pulls additional refrigerant gas into the

system until the full 9.1 pound (4.13 kg) charge is obtained. When the system is fully charged, immediately close the

air conditioner low pressure service valve and refrigerant drum valve.

21. Run the air conditioner in COOL mode (with TEMPerature control thermostat in full DECREASE position) for 15

minutes. The ambient temperature should be between 75 and 95 F (24 and 35 C).

CAUTION

Do not skip the next step. This is a necessary preparation inspection to insure

procedures were carried out correctly.

22. After 15 minutes, observe the sight glass on back of condenser section.

Green center means the refrige rant moisture content is acceptable.

Yellow center means there is too much moisture in the system. It must be discharged, evacuated, and charged

again.

Milky white or bubbly liquid means the system has a low charge.

NOTE

Bubbles may be visible at temperatures less than 70 F (21 C) or greater than 1000

F (38 C).

Clear bubble-free liquid around the center means the system is fully charged.

23.

If charge is low, add gas refrigerant.

Be sure that drum is switched to gas position. Open the drum valve and the air conditioner low pressure service

valve.

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