Refrigerant: Testing and Inspection

SIGHT GLASS REFRIGERANT LEVEL TEST
The sight glass is a refrigerant level indicator. To check the refrigerant level, clean the sight glass and start the vehicle engine. Push the air conditioning button to operate the compressor, place the blower switch to high and move the temperature control lever to MAX. COOL. After operating for a few minutes in this manner, check the sight glass.
1. If the sight glass is clear, the magnetic clutch is engaged, the compressor discharge line is warm and the compressor inlet line is cool; the system has a full charge.
2. If the sight glass is clear, the magnetic clutch is engaged and there is no significant temperature difference between compressor inlet and discharge lines; the system has lost most of its refrigerant charge.
3. If the sight glass shows foam or bubbles, the system could be low on refrigerant or the receiver drier is restricted. The system has to be tested, leak checked then recharged with refrigerant.




MAGNETIC CLUTCH
1. Disconnect the wiring to the magnetic clutch.
2. Connect battery (-) to compressor body.
3. Connect battery (+) voltage directly to the wiring for the magnetic clutch.
4. If the magnetic clutch is normal, there will be a "click". If the pulley and armature do not make contact ("click"), there is a malfunction.

RECEIVER DRIER
To Test the Receiver Drier
1. Operate the unit and check the piping temperature by touching the receiver drier outlet and inlet.
2. If there is a difference in the temperatures, the receiver drier is restricted.
Replace the receiver drier.




DUAL PRESSURE SWITCH (LOW PRESSURE SWITCH)
1. Turn back the adaptor valve handle all the way and install it to the low-pressure side service valve.
2. With the gauge manifold low-pressure service valves closed, connect the gauge manifold high-pressure side charging hose to the adaptor valve.
3. Tighten the adaptor valve handle and open the service valve.
4. It there is continuity between the dual pressure switch terminals when the low-pressure side pressure is at the level of dual pressure switch ON condition shown to the left, the switch is functioning normally. If not, replace the switch.




COMPRESSOR CHECK
After running the compressor for five minutes, check whether the following items are proper or not.







FIN-THERMO SENSOR
1. Disconnect the sensor connector at the evaporator case and by using an ohmmeter, measure the resistance. If the resistance is within ± 10% of value of the characteristic curve, the sensor is functioning normally.
2. If the sensor is normal, there is a malfunction of the air conditioning control unit and it should be replaced.