The EffikaK® SCD series spring-closed damper electronically regulales ìnlet air on gas-lired appliances. The spring-closed damper is constructed of stainless steel and is designed with a power open/spring-close operation using 120 VAC, 60 Hz control. An optional 24 VAC is available. When the appliance calls for the burner to fire, the damper motor energizes and rotates the damper blade into the open position. After the requirement for heat has been satisfied, the burner extinguishes and power is removed from the damper motor. This allows the spring to quickly return the blade to the closed position. Closing the damper keeps the residuai heat inside the appliance.