TM 5-3805-291-23-1
AIR CONDITIONING SYSTEM TESTS, INSPECTIONS, AND ADJUSTMENTS - CONTINUED
0018 00
REFRIGERANT QUICK-CHECK PROCEDURE FOR R-134A EXPANSION VALVE AND ORIFICE TUBE
SYSTEMS
0018 00
N OT E
In order to use this procedure, temperature of ambient air must be at least 70F (21C).
1.
Start engine and run engine at approximately 1,000 rpm. Move control knob on AC to position of MAXIMUM so cool-
ing is at a maximum in order to stabilize system, put fan switch in HIGH position and operate system for a minimum of
10 minutes (TM 5-3805-291-10).
2.
Check for restrictions present in refrigerant lines from compressor to inline dryer. Refrigerant lines and components that
are high pressure and high temperature come from outlet side of compressor. Lines go to inlet side of orifice tube. Outlet
side will be warm during normal operation. Heavy frost or a decrease in temperature in a line or in a component on high
pressure side may be an indication of a restriction or blockage.
a.
If there is no evidence of a restriction in condenser coil, inline dryer or refrigerant lines from compressor to inline
dryer, use procedure in step 3.
b.
If there is a restriction in condenser coil, inline dryer, or refrigerant lines from compressor to inline dryer, perform
the following procedures:
(1)
Recover refrigerant (WP 0222 00).
(2)
Remove restriction or replace component (WP 0223 00, WP 0224 00, and WP 0226 00).
(3)
Evacuate system (WP 0222 00).
(4)
Charge system with correct amount of refrigerant (WP 0222 00).
Perform a leak test. Refer to Refrigerant Leakage Test in this work package.
(5)
Perform a performance check. Refer to Performance Checks for Air Conditioning System in this work
(6)
package.
(7)
If problem still exists, go to step 4.
3.
Low system charge is indicated. Perform a leak test.
