TM 9-4120-398-14
5-10. CHARGING THE REFRIGERATION SYSTEM (cont)
l. Connect power.
m. Be sure circuit breakers are on.
n. Press and release both pressure switch reset buttons.
o. Turn air conditioner on and operate in the COOL mode with the temperature control thermostat set at a maximum
DECREASE position.
p. If the 11.0 pound (5.0 kg) full charge was obtained, skip steps q thru s. If the system pressure equalized prior to
obtaining a full charge of 11.0 pounds (5.0 kg), proceed with step q.
q. Switch the refrigerant drum to the gas only position.
r. Be sure that the refrigerant drum has been switched to the gas position and open the refrigerant drum valve and the
low (suction) pressure charging manifold valve.
s. Monitor the weight of the refrigerant drum as the air conditioner compressor pulls additional refrigerant gas into the
system until the full 11.0 pound (5.0 kg) charge is obtained. When the system is fully charged, immediately close the
refrigerant drum valve.
t. Run the air conditioner in COOL mode (with temperature control thermostat in full COOLER position) for 15
minutes.
Do not skip the next step.
u. After 15 minutes, observe the sight glass on back of condenser section. Green center means the refrigerant moisture
content is acceptable. Yellow center means there is too much moisture in the system. It must be discharged, evacuated, and
charged again.
NOTE
Milky white or bubbly liquid means the system has a low charge. Clear bubble-free liquid around the center
means the system is fully charged.
v. If charge is low, add gas refrigerant.
(1) Be sure that drum is switched to gas position. Open the drum valve.
(2) Continue to charge until sight glass is clear and bubble free.
(3) Close the refrigerant drum valve.
W.
Check air conditioner for proper cooling. There should be at least a 15F temperature difference between evaporator
discharge air and the inlet air. Turn the mode selector switch to OFF.
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