Front

HR-6 Compressor:

DESCRIPTION
The Cycling Clutch Orifice Tube (CCOT) refrigeration system is designed to cycle a compressor on and off to maintain desired cooling and to prevent evaporator freeze-up. Passenger compartment comfort is maintained by the temperature select bar on the controller.

OPERATION
Control of the refrigeration cycle (on and off operation of the compressor) is done with a switch that senses low side pressure as an indicator of evaporator pressure. During air temperatures of 60-80°F, the equalized pressures within the charged air conditioning system will close contacts of the pressure switch.

When an air conditioning mode is selected, voltage is supplied to the compressor clutch coil. As the compressor reduces the evaporator pressure to approximately 25 psi, the pressure switch will open, de-energizing the compressor clutch. As system equalizes and the pressure reaches approximately 46 psi, the pressure switch contacts close, re-energizing the clutch coil.

When the engine is turned off with the air conditioning system operating, the refrigerant in the system will flow from the high pressure side of the expansion tube (orifice) to the low pressure side until the pressure is equalized. This may be detected as a hissing sound for 30 to 60 seconds and is considered a normal condition.

The Blower Motor delivers air to the interior of the vehicle. Its speed is controlled by the Blower Switch and the Blower Resistor Assembly. When the Ignition Switch is in RUN, battery voltage is applied to the Blower Switch. With the Blower Switch in LO, voltage is applied across both Blower Resistors and the Blower Motor; the Blower Motor runs at its slowest speed. With the Blower Switch in MED, one of the Blower Resistors is bypassed; the Blower Motor runs faster. When the Blower Switch is set to HI, battery voltage is applied directly to the Blower Motor; the Blower Motor runs at its fastest speed.