Clutch Cycling Switch
In a (CCOT) cycling clutch orifice tube system, there's a constant pressure drop across the fixed orifice tube. It doesn't vary or change its output according to demands like an expansion valve does. A clutch cycling switch is used to activate and deactivate the compressor clutch instead. When the switch is stuck closed, the compressor clutch will remain engaged and not cycle. If it's stuck open, the compressor clutch will not engage and there will be no compressor operation.
The clutch cycling switch in the illustration is located on the accumulator, which is found on the low side of the system between the evaporator and the compressor. This system uses a clutch cycling switch to activate and deactivate the compressor clutch according to system pressure. This is why this system keeps cycling the compressor when the system is low or if there's resistance in the switch, the plug, or its related circuit. The same is true for a CCOT system that uses a thermostat to measure evaporator fin temperature to cycle the clutch. When the cycling clutch switch is operating correctly, this action should maintain the evaporator core at a cold, but not freezing 35° to 45° F.