Air Conditioning - Chevrolet LIGHT DUTY TRUCK (SERIES 10-35) Service Manual

Restriction in High Side o f System.
Visually Check for Frost Spot to Locate
Restriction. Repair as Necessary.
Evacuate & Charge
l
System
(O .K.)
RUNS CONTINUOUSLY
WITHIN LIMITS
Disconnect Blower W ire and Check For
C ycling Off at 138-193 kPa (20-28 PSI)
PRESSURE FALLS
BELOW 20 PSI
Defective Pressure
Switch
I
Replace. *Do Not Discharge
System. There is a Schrader
Valve in the Fitting
I
System
(O.K.)
A M BIEN T TEMP.
A/C
PICK-UP
O U T L E T
TEMP.
SU BU R B A N
OUTLET TEMPERATURE
WITHIN LIMITS
System
(O.K.)
MISSING
T
Install Expansion Tube
i
Evacuate 8t Charge
System
(O.K.)
--------------------------------SERVICE DIAGNOSTIC PROCEDURE----------------------------
INSUFFICIENT COOLING — A/C SYSTEM S W ITH CYCLING CLUTCH — EXPANSION TUBE
MOVE TEMP. LEVER RAPIDLY BACK AND FORTH
FROM HOT TO COLD. LISTEN FOR DOOR HITTING
This System Does Not Have a S ight Glass. Under No
Circum stances Should a Sight Glass Be Installed
Feel Liquid Line Before Expansion Tube
INLET PIPE AND OUTLET
PIPE SAME TEMPERA­
TURE OR OUTLET
COLDER THAN INLET
Install Gage Set and Check Com pressor
C ycling Press.
ON at 282.6-351.6 kPa (41-51 PSI)
OFF at 138-193 kPa (20-28 PSI)
CYCLES WITHIN LIMITS
CYCLES OFF AT 138-193
kPa (20-28 PSI) OR DOES
NOT PULL DOWN TO
PRESS.
Install Therm om eter in A/C Outlet and
Check Performance
SET TEMP. LEVER TO FULL COLD
SET SELECTOR LEVER TO MAX A/C
SET BLOWER SWITCH ON HI
CLOSE DOORS AND WINDOWS
RUN ENGINE AT 2000 R.P.M.
USE AUX FAN IN FRONT OF GRILL
21°C 27° C 32° C
(70° F) (80° F) (90° F)
5-8°C 5-8°C 6-10°C
(41-47) (41-47) (42-50)
6-9°C 6-9°C 10-14°C
(42-48) (50-58)
(42-48)
OUTLET TEMPERATURE
HIGH AS PER CHART
Check Compressor Cycling
ON CONTINUOUSLY
"D is c h a rg e System and Check For
Missing Expansion Tube
PLUGGED
Repair o r Replace Screen
I
Evacuate & Charge
i
System
(O.K.)
Chart 1 B-3~Pressure Cycling CCOT System Diagnosis
(PRESSURE SENSING)
AT EACH END
Feel Evaporator Inlet and O utlet Pipes
38° C 43° C
(100° F ) (110°F)
6-1 f C 6 -1 1°C
(43-57) (43-51)
12-17°C 14-19°C
(54-62) (57-67)
| IN PLACE |
Check Com pressor Inlet
Screen
i
___________ _ ___________
System Over Charged
I
Evacuate & Charge
I
System
(O.K.)
------ "W JP

AIR CONDITIONING

CYCLES HIGH OR LOW
(ON ABOVE 51 PSI
OR OFF BELOW 20 PSI)
Defective
Pressure
Switch
Replace
•Do Not Discharge
System. There
Is a Schrader
System
(O.K.)
CYCLE ON AND OFF OR
REMAINS OFF FOR LONG
PERIOD OF TIME
Discharge System and
Check fo r Plugged Expansion Tube
Replace
i
Evacuate & Charge
System
(O.K.)
LIGHT TRU CK S ER V IC E MANUAL
1B-19