CCOT Refrigeration System

CYCLING CLUTCH ORIFICE TUBE (CCOT) REFRIGERATION SYSTEM
The sole function of the refrigeration system is to maintain an evaporator core ambient temperature between approximately -1°C and 9°C (30.5.°F and 49°F) when refrigeration is required. The major components are the compressor, condenser, evaporator, expansion (orifice) tube and the accumulator. The components are interconnected by hose and tubing connections. This system incorporates the cycling clutch expansion (orifice) tube-type refrigeration system called CCOT.

The refrigeration system is controlled by an A/C Programmer (ACP) with input from a low-side refrigerant temperature thermistor which turns the compressor "ON" and "OFF" as required to prevent evaporator condensate freeze. The compressor runs only as much as necessary, resulting in fuel savings and less engine strain. An explanation of the refrigeration cycle and a brief description of each component follows:
The cycling clutch-expansion tube refrigeration system exhibits the same characteristics as previous systems.

-> During Electronic Climate Control (ECC) cooling operating conditions, slight increases and decreases of engine speed/power may be noticed. This characteristic should be considered normal as the system is designed to cycle the compressor on and off to maintain desired cooling. This reduced compressor operation benefits fuel economy.

-> The compressor low-pressure switch protects the compressor from operating if a low-charge condition exists. Additional compressor protection comes from the operating characteristics of the CCOT system. If a partial low-charge condition exists, or the expansion (orifice) tube becomes partially blocked, low-side pressure could be too low (cold) to allow the A/C programmer to turn on the compressor clutch for a normal cycle. This will be evidenced by rapid compressor clutch cycling and relatively warm air being discharged from the A/C outlets. If these conditions occur, the system should be repaired before compressor damage is incurred. If the charge drops to 1/4 of full charge, the AC programmer will set failure Code A047 and disengage the compressor.

-> When the ignition is turned "OFF" and the air conditioning has been operating, the refrigerant in the system will continue to flow until pressure is equalized. This may result in a faint sound of liquid flowing for 30 to 60 seconds and should be considered normal.

-> An anti-slugging feature is incorporated which will remove liquid refrigerant that may collect at the compressor. This operation will normally occur once a day after prolonged (overnight) soak of several hours. On initial crank the Air Conditioning Programmer (ACP) will check for indications of this condition and if found, the A/C clutch will engage. After the engine is started or shortly thereafter, the clutch will disengage and wait until the normal calibrations and parameters are met to signal re-engagement of the clutch.