How to Use Air-con Manifold Gauges
How to Use A/C Manifold Gauges
Ray Strobo
Instructions
Step 1:
Connect the low side hose (blue) to the low side port on the A/C unit.
Step 2:
Connect the high side hose (red) to the high side port on the A/C unit.
Step 3:
Open both valves so that the gauges register the A/C system pressure.
Step 4:
Compare the actual PSI readings to the normal PSI readings with the A/C system in the “off” position (static pressure). The normal reading on both the high side and the low side should be 80 to 105 PSI.
Step 5:
Turn the A/C system on to “max/high” output. With the engine speed at about 1,000 RPMs, check the low side PSI reading, which should be about 25 to 35 PSI, then check the high side PSI reading, which should be about 200 to 350 PSI. If the PSI readings are lower than normal, hook up a can of refrigerant to the yellow hose and add enough refrigerant to the system to bring the PSI readings up to the normal ranges.
Tips & Warnings
The low and high hoses have different size connectors.The owner’s manual may have specific PSI ranges for your car’s make and model.If the PSI readings are normal and the system is still blowing hot air, you may need to consult an auto A/C professional.
Do not add refrigerant to the system without first using the manifold gauges to check the refrigerant level. Do not overfill the system with refrigerant. Excess refrigerant must be removed by a professional and exhausted into a proper container.
How to Use A/C Manifold Gauges article by eHow.com
