Chimney Safety Institute of America (CSIA) Certification Practice Test

Which component is commonly used as the stack control in newer oil-fired appliances?

1. Thermostatic control

2. Photo sensitive cad cell relay

3. Mechanical switch

4. Electric relay

The correct answer is: Photo sensitive cad cell relay

The photo sensitive cad cell relay is commonly used as the stack control in newer oil-fired appliances due to its ability to detect the presence of flame by using a photoconductive cell. When the flame is detected, the cad cell relay enables the burner operation, ensuring safety and efficiency in the ignition process. If the flame goes out or is not detected, the relay will shut down the burner to prevent unburned fuel from entering the combustion area, thereby reducing the risk of fire hazards and optimizing fuel usage. This technology allows for more reliable flame sensing compared to older methods, which often relied on mechanical or electrical switches. By using a photo sensitive device, it improves response time and adaptability to various conditions within the appliance, making it a preferred choice in modern oil-fired systems. The cad cell effectively enhances overall safety and operational performance in these appliances.