TM 5-2420-230-24-1
Contact with refrigerant can cause frostbite. Keep hands and face away to prevent personal injury.
Protective goggles must always be worn when refrigerant lines are opened, even if the gauges
indicate the system is empty.
Do not smoke when servicing air conditioners or wherever refrigerant gas may be present. Personal
injury or death can result from inhaling refrigerant through a lit cigarette.
Personal injury or death can result from inhaling refrigerant. Only vent refrigerant in a
well-ventilated area.
NOTE
Only open manifold gage set valves long enough to purge air from charging hose.
(5)
Slowly open valves (2) and (3) and purge air from charging hose (6).
(6)
Attach charging hose (6) to recovery station inlet (7).
NOTE
One valve is for vapor and the other valve is for liquid.
(7)
Ensure valves on refrigerant recovery tank (8) are open.
(8)
Follow recovery station OEM instructions and recover R-134a refrigerant.
c. Evacuation.
Moisture will combine with metals in the refrigerant system and this will produce highly corrosive
by-products. The by-products are oxides, iron hydroxide, and aluminum hydroxide and they will
damage the A/C system.
Moisture in the A/C system can freeze and damage the expansion valve and orifice tube. If there is
water in the system the water must be removed.
NOTE
If replacement of a component is necessary or repair of a component is necessary, refrigerant must
be recovered from A/C system.
If A/C system has lost any charge after a long period of time, refrigerant in A/C system must be
recovered.
It is necessary to perform evacuating procedure to delete all air and moisture from the A/C system.
A complete charge must never be given to a system without first performing the evacuating
procedure.
If the system has been left open for more than a half hour, the system has been exposed to air and moisture. A new
receiver-dryer must be installed (Para 19-9).
NOTE
Evacuating the A/C system with a vacuum pump will boil and remove any water in the system.
Remove water from the A/C system by evacuating the system with a vacuum pump (Table 19-1).
19-5
