TM 9-4120-399-14
WARNING
DANGEROUS CHEMICAL
(R22)
is used in this equipment.
DEATH
or severe injury may result if personnel fail to observe safety
precautions. Use great care to avoid contact with liquid refrigerant gas being
discharge 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 refrigerant to break down and form carbonyl
chloride (phosgene), a highly poisonous and corrosive gas.
(3) Remove protective caps from charging valves.
(4) Connect individual pressure gages, or a refrigeration charging manifold and hoses to
the high (discharge) and low (suction) charging valves.
CAUTION
Take care that only a very small amount of refrigerant is allowed to
escape during hose purging. Large amounts of escaping refrigerant will
freeze components.
Loosen hose connections at gages or charging manifold.
(5)
Open high (discharge) high pressure manifold valve slightly to purge air from hose.
(6)
Tighten low pressure hose connection at gage fitting as soon as a hissing sound is
Heard.
Open low (suction) pressure manifold valve slightly to purge air from hose. Tighten
(7)
low pressure hose connection at gage fitting as soon as a hissing sound is heard.
(8) Open the low (suction) and high (discharge) manifold valves.
(9) Both gages should read the same. Check the reading with the appropriate column
in Table 5-1. 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.
(10) Turn the mode selector switch to the COOL mode with the temperature control
thermostat in the full DECREASE setting for a few minutes.
(11) With the unit operating, allow gages to stabilize. Take readings of the two gages.
5-20
