What is the purpose of the cad cell in a cad cell primary control?

The cad cell, or cadmium sulfide light sensor, plays a crucial role in a cad cell primary control system by proving ignition. When a burner ignites, it produces light, and the cad cell detects this light to confirm that the flame is present. If the cad cell does not detect flame or light, it interrupts the flow of fuel to the burner, thereby preventing unsafe conditions such as fuel accumulation or explosions. This safety mechanism is essential in ensuring that the heating system operates effectively and safely.

The other functions listed in the options are not the primary role of the cad cell. Temperature regulation, fuel level monitoring, and airflow control involve separate mechanisms and sensors designed specifically for those tasks. The cad cell’s unique function focuses solely on confirming that ignition has occurred, which is critical for the safe operation of appliances that rely on combustion.