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TRUCK SERVICE MANUAL
TM 5-4210-230-14&P-1
BODIES AND CABS
AIR CONDITIONING PERFORMANCE CHECK (PRESSURE
TEST)
This performance test can be used to determine if the
air conditioning system is properly charged and functioning
correctly.
The procedure for making the performance check
utilizing the SE-2443 Portable Service Station is outlined
below.
1.
Park vehicle in an area with low air movement.
Place transmission in neutral and apply brake.
2.
Open cab doors. Close all cab ventilators. Raise
hood.
3.
Connect SE-2443 Service Station to air conditioning
system service ports as follows: (See Fig. 35)
a.
Close manifold suction and pressure gauge
valves. (Turn fully clockwise.)
b.
Remove cap from compressor suction service
port. Connect manifold suction gauge hose to
compressor suction service port.
c.
Remove cap or engine fan drive override
switch
(if
equipped)
from
compressor
discharge service port.
Connect manifold discharge gauge hose to
compressor discharge service port.
Fig. 35 Manifold and Garage Set Connected to Compressor
Service Port
4.
Position a thermometer about 305-610 mm (12-24")
in front of vehicle grille to measure ambient
temperature of air entering condenser.
5.
Insert
another
thermometer
through
center
of
passenger air conditioning air outlet. Do not let
thermometer touch side of air duct.
6.
Set air conditioning controls for maximum cooling
(A/C lever at "COLD", blower switch on "HIGH").
7.
Operate engine at RPM specified in "Engine Speed
Chart" under SPECIFICATIONS for about ten (10)
minutes. Then:
a.
Observe and record ambient temperature of
air centering vehicle grille.
b.
Observe
and
record
cool
air
outlet
temperature.
c.
Observe and record discharge and suction
pressure gauge readings.
8.
To evaluate air conditioning system performance,
compare readings obtained in Step 7 with those
listed in the "Operating Pressure Test Chart" under
SPECIFICATIONS.
If readings obtained from vehicle are not within limits
specified in the chart, refer to TROUBLE SHOOTING
GUIDE for causes of abnormal pressures. Make
necessary repairs.
9.
After pressure test is completed disconnect manifold
and gauge set hoses from compressor service ports.
Install cap on compressor suction service port.
Install cap or fan drive override switch (if equipped)
on compressor discharge service port.
IMPORTANT
To keep foreign material out of manifold and
gauge set hoses, always attach ends of hoses
to bracket on service station when not in use.
10.
Check air conditioning system for refrigerant leaks
using an electronic leak detector. Follow equipment
manufacturer's instructions.
11.
Close hood and cab doors.
DISCHARGING THE AIR CONDITIONING SYSTEM
Whenever it becomes necessary to open the air
conditioning
refrigerant
system
to
remove
or
service
components, the refrigerant charge must be removed from the
system.
To discharge the system, utilizing the SE-2443
Portable Service Station, proceed as outlined below:
CTS-2731 Page 21
PRINTED IN UNITED STATES OF AMERICA
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