Refrigerant: Testing and Inspection

ON-VEHICLE INSPECTION

1. AIR CONDITIONER FUNCTION CHECK




a. Set the manifold gauge set.
b. Set the vehicle to the conditions (Procedure "A").
c. Place a dry and wet bulb thermometer at the air inlet opening and insert the bulb of a dry bulb thermometer at the center of the air outlet opening.
d. Operate the air conditioner with the vehicle in condition (See procedure "A"), and stabilize the air outlet opening temperature (approximately 5 to 6 minutes).
e. Measure the dry and wet bulb temperature at the air inlet opening and the dry bulb temperature at the air outlet opening.




f. Using the psychrometric chart, determine the relative humidity value, based on the measured values of the wet and dry bulb thermometers in the inlet.




1. For example, when the dry-bulb temperature is 25 °C (77 °F) and the wet-bulb temperature is 19.5 °C (67.1 °F), the relative humidity value is 60% which is shown in the psychrometric chart as the point where the 2 dotted lines intersect.




g. Using the standard performance chart, find the point where the difference between the temperatures measured in the inlet and outlet, and the relative humidity intersect.

The intersecting point is within the diagonal range shown in the chart.




1. For example, when the difference between temperatures measured in the inlet and outlet is 17 °C (62.6 °F) and the relative humidity is 60%, the intersecting point is within the diagonal range. Therefore this air conditioner is normal.

2. INSPECT REFRIGERANT VOLUME







a. Check the sight glass on the air conditioning tube & accessory assembly.
Test conditions:
- Engine is running at 1,500 rpm
- Blower speed control switch is at "HI"
- A/C switch is ON
- Temperature control dial is at "MAX. COOL" position
- Doors are fully open

3. INSPECT REFRIGERANT PRESSURE WITH MANIFOLD GAUGE SET
a. This is a method in which the trouble is located by using a manifold gauge set. 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




1. Normally functioning refrigeration system
Gauge reading:
Low pressure side: 0.15 to 0.25 MPa (1.5 to 2.5 kgf/sq.cm)
High pressure side: 1.37 to 1.57 MPa (14 to 16 kgf/sq.cm)




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 present in refrigeration system




8. Expansion valve malfunction




9. Defective compressor




Gauge readings (Reference)