TM 5-2410-240-23-3
0254
EVACUATION
000254
C AU T I O N
Moisture will combine with metals in refrigerant system to produce highly corrosive
byproducts. Byproducts are oxides, iron hydroxide, and aluminum hydroxide, and they will
damage A/C system.
Moisture in A/C system can freeze and damage expansion valve and orifice tube. If there
is water in A/C system, it must be removed.
Failure to follow these cautions ma result in damage to equipment.
y
N OT E
If replacement or repair of component is nec ssary, refrigerant must be recovered from
e
A/C system.
If A/C system has lost any ch rge after a long period of time, refrigerant in A/C system
a
must be recovered.
Perform evacuating procedures to removeall air and moisture from A/C system.
A complete charge must never be given toA/C system without first performing evacuating
procedures.
If A/C system has been left open for more than 30 minutes, A/C system has been exposed
to air and moisture. New receiver dryer must be installed.
Evacuating A/C system with vacuum pump willboil and remove any water in A/C system.
Remove water from A/C system by evacuating A/C system with vacuum pump.
1. Install blue low-side hose (Figure 2, Item 3) on suction (low) side of A/C compressor.
2. Install red high-side hose (Figure 2, Item 2) on discharge (high) side of A/C compressor.
3. Follow recovery station OEM instructions to evacuate A/C system.
N OT E
At high elevations, less vacuum is required. At sea level, 28 to 29 in Hg (95 to 98 kPa) is
the required specification. For every 1,000 ft (305 m) above sea level, decrease the
required specification by 1 in Hg (3 kPa).
AMBIENT
VACUUM REQUIRED TO BOIL WATER
TEMPERATURE F (C)
IN A/C SYSTEM IN. HG (KPA)
100F (38C)
28 in Hg (95 kPa)
90F (32C)
28.5 in Hg (96.5 kPa)
81F (27C)
28.8 in Hg (97.5 kPa)
70F (21C)
29.2 in Hg (98.8 kPa)
0254-4