— Field Controls Company Your Number One Draft Choice THERMAL SAFETY SWITCHES 2308 Airport Road Kingston, NC 28601 [1] Vomits Amps. 120 A.C. 12 240 A.C. 8 30 D.C. 12 125 D.C. 1 Switch Operation: Thermal Switches are flue gas spillage safety devices. They detect spillage of flue gas products due to a blocked Hue system or inadequate draft, The switch senses the spillage of hot flue gases and DE-energizes the system's burner control within 2 minutes.