Chrysler DODGE D150 1993 Service Manual page 1449

2 4 - 1 2 HEATING AND AIR CONDITIONING
PERFORMANCE TEMPERATURE CHART
Garage Ambient Temperature
21 °C
(70°F)
26.5°C
(80°F)
32°C
(90°F)
3/.5°'J
(100T)
43°C
(110°F)
Discharge Air Temperature
3-10°C
(38-50°F)
6-12°C
(42-54'F)
8-14°C
(46-58°F)
10-17°C
(50-62°F)
12-19°C
(54-66°F)
Compressor Discharge Pressure
1344 a 1620 a
1861 k P a g
2103 a
1 3 7 9
k P c g
2344 a
Compressor Discharge Pressure
120 •
195 P S ' 9
160 .
235 P S ' 9
200 .
270 P S ' 9
240 .
305 P S ' 9
280 .
340 P S ' 9
Evaporator Suction Pressure
1 2 4 kPag
207 a
1 3 8 kPag
241 J 269 k P a g
III k P ° 9
296
179 ,
D
324 k P a g
Evaporator Suction Pressure
18 .
30 P S ' 9
20 .
35 p S ' g
22
39 p S , g
25 .
43 p S ' g
26 .
47
p S
'
9
J9124-97
pressure must drop to below -50 kPag (15 inch of vacu­
um). If the condition is not met the H-valve is stuck
open and should be replaced. Remove Liquid C 0
2
and
watch evaporator suction pressure; it should increase to
a minimum of 262 kPag (38 psig) and then stabilize to a
pressure of 172-240 kPag (25-35 psig). Any H-valve
which does not produce this response is stuck open and
should be replaced.
(4) Connect A/C water valve vacuum hose (gray)
and set temperature control in cool position.
(5) Set engine speed at 1,000 RPM and blower on
HI. The evaporator suction pressure should be in the
range of 138-207 kPag (20-30 psig). If compressor dis­
charge is higher t h a n 1 656 kPag (240 psig), check
for restricted discharge line, radiator overheating, air
in system or faulty viscous fan drive. If discharge
pressure is less t h a n 966 kPag (140 psig), check com­
pressor head gaskets and discharge reeds.
(6) Connect the electrical wires to the electronic
temperature cycling clutch switch.
VACUUM CONTROL SYSTEM ADJUSTMENTS
AND TESTS
To keep the vacuum harness in place, common vi­
nyl tape (sometimes called plastic tape of electri­
cian's tape) cannot be used. It will cause the tube to
deteriorate directly under the tape, when high under­
hood temperatures are involved. A compatible nylon
type of tape such as MS CH69 (#281) or an equiva­
lent must be used.
The test of the push button switch operation deter­
mines whether or not the vacuum and electrical cir­
cuits are properly connected and the controls are
functioning properly. However, it is possible t h a t this
system operating perfectly at engine idle during high
manifold vacuum, may not function properly at high
engine speeds. Before starting this test, stop engine
and make certain the vacuum source hose at engine
intake manifold is tight on its connector.
EXPANSION (H) VALVE TEST
Test must be made at ambient temperature of
21°C-29°C (70°F-85°F).
After performing all previously mentioned tests,
conduct the H-valve test as follows:
(1) Operate the engine at 1,000 RPM with the win­
dows closed. Set air conditioning controls for MAX
A/C, high blower, temperature control lever in full
reheat position and cycling clutch switch electrically
bypassed. Disconnect and plug the water valve vac­
uum hose in the engine compartment.
(2) Operate the system for at least 5 minutes in or­
der to obtain partial stabilization and sufficient re­
heat to load the system. Pressure at the discharge
service port should reach 966-1 656 kPag (140-240
psig) (Fig. 6). If head pressure of 966-1 656 kPag
(140-240 psig) cannot be obtained, check system
charge level.
Fig. 6 Expansion (H) Valve Test
W A R N I N G : E X T R E M E C A R E M U S T B E U S E D W H E N
H A N D L I N G L I Q U I D C 0
2
A S S K I N I N J U R Y C A N O C ­
C U R IF P R O T E C T I V E G L O V E S A R E N O T W O R N .
(3) Put Liquid C 0
2
on control head (completely cover
head) for a minimum of 30 seconds. Evaporator suction