Refrigerant: Testing and Inspection
ON-VEHICLE INSPECTION1. INSPECT REFRIGERANT VOLUME
a. Check the sight glass on the air conditioning tube & accessory assembly.
1. Prepare the vehicle according the chart.
2. Compare the sight glass to the following chart.
2. INSPECT REFRIGERANT PRESSURE WITH MANIFOLD GAUGE SET
HINT: This is a method where a manifold gauge set is used to help locate the problem.
a. Read the manifold gauge pressure when these conditions are established. Test conditions:
- Temperature at the air inlet with the switch set at RECIRC is 30 to 35 °C (86 to 95 °F)
- Engine is running at 1,500 rpm
- Blower speed control switch is at "HI"
- Temperature control dial is at "COOL"
- A/C switch is ON
- Doors are fully open
- Ignition switch in a position that enables the AC compressor to run.
1. Normally functioning refrigeration system
Gauge reading:
Low pressure side: 0.15 to 0.25 MPa (1.5 to 2.5 kgf/sq.cm, 21.3 to 35.5 psi)
High pressure side: 1.37 to 1.57 MPa (14 to 16 kgf/sq.cm, 199.1 to 227.5 psi)
2. Moisture is present in refrigeration system.
3. Insufficient cooling
4. Poor circulation of refrigerant
5. Refrigerant does not circulate.
Part 1:
Part 2:
6. Refrigerant is overcharged or cooling effectiveness of condenser is insufficient.
7. Air is present in refrigeration system.
8. Expansion valve malfunction
9. Insufficient compressor compression
Gauge readings (Reference)