The contactor in an air conditioning system is controlled by the cooling thermostat, which signals the contactor to start the cooling process when the room temperature exceeds a set threshold. The correct answer is option C.
The correct option to control the contactor in an air conditioning system, under normal operating conditions, is the Cooling Thermostat. The cooling thermostat plays a pivotal role in regulating the temperature within a room. When the thermostat detects that the temperature has risen above the set point, it sends a signal to engage the contactor. This activation allows electrical power to flow to the air conditioner's compressor and fan motors, initiating the cooling cycle.
The other options provided, namely a disconnect switch and a high-pressure switch, serve different purposes. A disconnect switch is utilized for manually disconnecting power, while a high-pressure switch is designed to interrupt power in the event of excessive pressure in the system, preventing potential damage. However, neither the disconnect switch nor the high-pressure switch functions to control the operation of the contactor under normal conditions; that role is specifically attributed to the cooling thermostat.
Therefore, option C is correct.