A/C System Tests

Pressure Test

Performance Test






The performance test will help determine if the air conditioner system is operating within specifications.

Use only service equipment for refrigerant HFC-134a (R-134a).

If accidental system discharge occurs, ventilate work area before resuming service.

R-134a service equipment or vehicle air conditioning systems should not be pressure tested or leak tested with compressed air.

Additional health and safety information may be obtained from the refrigerant and lubricant manufacturers.

1. Connect a R-134a refrigerant recover/recycling/charging station to the high-pressure service port and the low-pressure service port, following the equipment manufacturer's instructions.

2. Determine the relative humidity and air temperature.

3. Insert a thermometer in the center vent.

4. Test conditions:

Avoid direct sunlight.

Open the hood.

Open the front doors.

Set the temperature control dial to Max Cool, the mode control dial to Vent and the recirculation control lever to Recirculate.

Turn the A/C switch on and the fan switch on Max.

Run the engine at 1,500 rpm (min-1).

No driver or passengers in vehicle.

5. After running the air conditioning for 10 minutes under the above test conditions, read the delivery temperature from the thermometer in the center vent, the intake temperature near the blower unit behind the glove box and the high and low system pressure from the A/C gauges.

6. To complete the charts:

Mark the delivery temperature along the vertical line.

Mark the intake temperature (ambient air temperature) along the bottom line.

Draw a line straight up from the air temperature to the humidity.

Mark a point 10 % above and 10 % below the humidity level.

From each point, draw a horizontal line across the delivery temperature.

The delivery temperature should fall between the two lines.

Complete the low-side pressure test and high-side pressure test in the same way.

Any measurements outside the line may indicate the need for further inspection.