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ARMY TM 9-4120-381-14
NAVY EE-000-CA-MMA-010/7053-AC
AIR FORCE TO 35E9-136-31
5-18.
REFRIGERANT PRESSURE CHECK-Continued.
SERVICE-Continued
g.
Open manual service valve (para 5-39).
h.
Adjust cool control thermostat (para 4-87) to lowest temperature setting.
i.
Connect air conditioner input power at source.
j.
Turn MODE SELECT SWITCH to COOL mode.
k.
With unit operating, allow gauges to stabilize. Take readings of the two gauges.
(1)
If discharge and suction pressures are at, or near, same value, a pressure equalizer solenoid valve malfunction
or an internal compressor failure is indicated.
(2)
If discharge pressure is low and suction pressure is normal, (refer to Table 5-3), a low refrigerant charge is
indicated.
(3)
If discharge pressure is normal and suction pressure is either high or low, failure or maladjustment of the
pressure regulator valve or expansion valve is indicated.
(4)
If discharge pressure is high and suction pressure is normal, a malfunction of the condenser fan, refrigerant
overcharge, or clogged filter drier is indicated.
I.
When pressure tests are completed, proceed with maintenance action indicated.
m.
Turn mode switch to OFF.
n.
Disconnect air conditioner input power at source.
o.
Remove jumper wires installed in step f.
FOLLOW ON PROCEDURE
1.
Reset cool control thermostat (para 4-87).
2.
Close left electric plate (para 4-30).
3.
Remove service manifold hoses from service valves.
4.
Install protective caps (para 5-11) to high and low pressure service valve stems.
5.
Connect air conditioner input power at source.
Table 5-3.
Normal Operating Pressures (In Full Cooling Mode)
5-36
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