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 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.
Test conditions used to determine system operation:
A. Place Temperature probe (thermometer) into center outlet.
B. Connect the gauges or service equipment to the High/Low charging ports.
C. Place Blower fan switch on Medium
D. Close all doors and windows in the vehicle.
E. Place shop fan or heavy-duty squirrel-cage blower directly in front of the condenser
F. Run engine idle up to 1500 RPM.
These test conditions will simulate the effect 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.
Charges as follows R134A = 1.8 lbs. R12 = 2.0 lbs.
No additional oil is necessary in new compressors
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III. TYPICAL PROBLEMS ENCOUNTERED IN CHARGING SYSTEMS
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A. NOISY COMPRESSOR
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1. A noisy compressor is generally caused by over charging the system or introducing outside air into the system.
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a. If a system is over charged 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 pressure. System must be evacuated according to weight specifications.
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b. If air is introduced into the system during the charging process, 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 the exact weight specifications making sure to bleed any air from lines when introducing the refrigerant.
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B. SYSTEM NOT COOLING
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1. There are numerous factors that can cause the cooling to be less than optimal.
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a. Improper charge in the system - Improper charging is the number one cause of system failure. The pressure readings should be taken before any determination can be made. High or low readings in direct proportion to the normal pressures (see sect. II) will tell you if the charge is too high or low. Excessive system pressure can also cause vibrations and whistling noise from the expansion valve and refrigerant lines.
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b. Heater control valve installation - Installing the heater control valve in the incorrect hose will allow water to collect in the unit. The heater control is a directional valve; make sure the water flow is with the direction of the arrow. As the engine heats up the water transfers the heat to the coil, thus overpowering the a/c coil. A leaking or faulty valve will have a more pronounced affect on the unit’s cooling ability. Installing the valve improperly (such as having the flow reversed) will allow water to flow through, thus inhibiting cooling. Check for heat transfer by disconnecting hose from the system completely. By running down the road with the hose looped back through the motor, you eliminate the possibility of heat transfer to the unit. Move or replace the valve if necessary.
Notes:
Gas charging is safest; however, most compressors today do have anti-slug valves. Always charge with manufacturers recommended charge. If you don't think the charge is working correctly, call Vintage Air
Oil:
New compressor - no additional oil needed - if using remote condenser or rear-mounted system, call Vintage Air for advice on possible additional refrigerant.
Used compressors - call Vintage Air for Leak check - dye - soap/water Recommendations
Inject a quality leak detection dye at time of charging
Bead lock fittings crimped with (bubble crimp) crimping tool is best option with barrier hose
NOTE: This procedure applies when using complete Vintage Air System only.