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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..
This task covers: Service
INITIAL SETUP:
Tools:
Tool kit, service, refrigeration unit (Item 1, Appendix B)
Gloves, chemical (Appendix C)
Goggle, industrial (Appendix C)
Personnel: 1
SERVICE
WARNING
Death or serious injury may result if personnel fail to observe safety precautions. Use great care to
avoid contact with liquid refrigerant or refrigerant gas being discharged under pressure. Sudden and
irreversible tissue damage can result from freezing. Wear thermal protective gloves and a face
protector or goggles in any situation where skin-eye-contact is possible. Prevent contact of
refrigerant gas with flame or hot surfaces. Heat causes the refrigerant to break down and form
carbonyl chloride (phosgene), a highly poisonous and corrosive gas.
1.
Except in cases where it is obvious that the refrigerant charge has been lost, the first step in troubleshooting
problems in the refrigeration system should be to check discharge and suction pressures under operating
conditions.
2.
Check pressures as follows:
a.
Turn mode selector switch to OFF.
b.
Connect service manifold (para 5-11).
c.
Both gauges should read the same. Check the reading with the appropriate column in Table 5-2. If the
system is even partially charged, the pressure should be approximately equal to that shown in the table for
the appropriate ambient temperature. If the pressure is considerably less than shown in the table, the
system does not contain enough refrigerant to continue the pressure check; go to leak testing (para 5-15).
WARNING
Disconnect input power to the air conditioner before performing any internal maintenance or adjusting
thermostat. Voltages used can KILL. Shutting the unit off at the control panel does not disconnect unit
power.
d.
Disconnect air conditioner input power at source.
e.
Open left electric plate (para 4-30).
NOTE
If air conditioner is configured for dual operation, jumper wires need to be installed for single mode
operation refrigerant testing.
f.
Install jumper wires to TB2 (para 4-61) for single mode operation. (See Figure FO-3)
5-34
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