- The sight glass is an indicator of the refrigerant level in the air conditioning system. To check the level, clean the glass and start the engine (pic. 18.1). Press the air conditioning compressor start button, set the fan switch to the maximum speed position, and set the air temperature control knob to the maximum cooling position. After a few minutes of operation of the air conditioner in this mode, look through the viewing window.
Pic. 18.1. Location of the viewing window for checking the refrigerant level
1. If the sight glass is clear, the compressor magnetic clutch is engaged, the compressor discharge hose is warm, and the inlet hose is cold, the system is completely filled with refrigerant.
2. If the sight glass is clear, the electromagnetic clutch is engaged, however, there is no significant temperature difference between the discharge and inlet hose, which means that part of the refrigerant has escaped from the system.
3. If foam or bubbles are visible in the sight glass, this indicates insufficient refrigerant. The system needs to be recharged with refrigerant.