TROUBLESHOOTING GUIDE
The following guide will help the installer determine if a problem exists in the system that would cause a malfunction. If you are experiencing problems in the physical operation of the unit ( blower speeds, door operation, etc.), we encourage you to refer to the wiring diagram located in the instruction manual. Using a continuity or light tester you can solve many of the simple problems by tracing all connections and testing them individually. However, if the unit is functioning correctly, but it is not cooling, you can refer to the following guide that will outline the most common problems encountered by installers.
I. TEST CONDITIONS USED TO DETERMINE SYSTEM OPERATION
A. PLACE TEMPERATURE PROBE (THERMOMETER) INTO CENTER OUTLET.
B. CONNECT GAUGES OR SERVICE EQUIPMENT TO HIGH/LOW CHARGING
PORTS
C. PLACE BLOWER FAN SWITCH ON MEDIUM.
D. CLOSE ALL DOORS AND WINDOWS ON VEHICLE.
E. PLACE SHOP FAN OR HEAVY DUTY? SQUIRREL-CAGE BLOWER
DIRECTLY IN FRONT OF CONDENSER.
F. RUN ENGINE IDLE UP TO 1500 RPM.
(THESE TEST CONDITIONS WILL SIMULATE THE AFFECT OF DRIVING THE VEHICLE AND GIVE THE TECHNICIAN THE THREE CRITICAL READINGS THAT THEY WILL NEED TO DIAGNOSE ANY POTENTIAL PROBLEMS )
II. ACCEPTABLE OPERATING PRESSURE RANGES FOR VINTAGE AIR SYSTEMS
A. R134A TYPE
1. HIGH-SIDE PRESSURES ( 160-250 PSI ) * Note- general rule of thumb is two times the ambient ( daytime ) temperature,? plus 15-20%.
2. LOW-SIDE PRESSURES ( 06-12 PSI in a steady state)
3. CENTER DUCT TEMPERATURE ( 36-46 DEGREES F.)
B. R12 TYPE
1. HIGH-SIDE PRESSURES ( 140-230 PSI ) * Note- general rule of thumb is two times the ambient ( daytime ) temperature,? plus 15%.
2. LOW-SIDE PRESSURES ( 12-15 PSI in a steady state)
3. CENTER DUCT TEMPERATURE ( 36-46 DEGREES F.)
Charge as follows:?? R134A = 1.8 lbs R12= 2.0 lbs
No additional oil is necessary in new compressors
III. TYPICAL PROBLEMS ENCOUNTERED IN CHARGING SYSTEMS
A. NOISY COMPRESSOR
1. A noisy compressor is generally caused by overcharging the system or introducing outside air into the system.
a. If the system is overcharged both gauges will read abnormally high readings.
This is causing a feedback pressure on the compressor causing it to rattle or shake from the increased? cylinder head pressures. System must be evacuated and re-charged to exact weight specifications.
b. If air is introduced into the system during charging it will introduce moisture that will cause ice to form in the refrigerant flow and will cause the compressor to rattle or growl under acceleration. System must be evacuated and re-charged to exact weight specifications making sure to bleed any air from lines when introducing the refrigerant.