Komatsu PC88MR-10 Shop Manual page 1352

80 Appendix
Input and output signals of the air conditioner controller
5. The air conditioner controller detects the evaporator temperature using the evaporator temperature
sensor.
6. In order to prevent freezing of the evaporator, the air conditioner controller controls the compressor by
turning the compressor clutch relay ON and OFF.
a When the dual pressure switch detects a pressure abnormality (i.e., turns OFF), the air conditioner
controller turns the compressor clutch relay OFF, and therefore, the compressor stops operating.
7. When performing automatic air conditioning, the air conditioner controller controls the inside (air)
temperature to the set temperature and adjust the air flow according to the data from the sunlight sensor,
the outside air temperature sensor, and the inside air temperature sensor.
8. The air conditioner controller has the self-diagnosis function. If any abnormality is detected, the controller
notifies it to the machine monitor by the CAN communication. Then, failure code [879***] is displayed on
the "Electrical Systems" screen of the electrical system on the machine monitor.
80-28 PC88MR-10