Lubricate the clutch assembly

Lubricate the heat exchangers

Circulate oil back to compressor

Lubricate the moving parts of TEV

Thermostat, LPC, HPC

LPC, Blower Fan Motor

HPC, Condenser Fan Motor

Thermostat, Condenser Fan Motor

Check Rpm of engine shaft

Check Rpm of compressor shaft

Start and stop the evaporator blower

Start and stop the compressor electro magnetically

LPC, HPC and Blower-switch

Thermostat, Electromagnetic clutch, on-off control

Thermostat, Thermostatic expansion valve, Blower-switch

Thermostat, Low-pressure control and high pressure control

Drain pan is leak proof

Leakage of evaporator coil

Poor insulation at the bottom of drain pan

Worn out shock absorbers on the bus wheels