The Fenwal 35-605606-227 DSI Control Module is a 24V direct spark ignition control designed for reliable and safe operation in gas-fired HVAC systems such as furnaces, boilers, and unit heaters. It provides precise control with a 30-second pre-purge, 15-second trial for ignition, and up to three ignition attempts for enhanced safety. https://www.partshnc.com/35-605606-227-fenwal-24vdsi30secpp-15sectfi3trys