The Automag AA Series 24V 1" zone valve's normally open design make them ideal for use as a dump zone control valve on piping systems for Solid Fueled Boilers. When there is no power to the Automag zone valves quickly go to their normal position, allowing water to flow. This zone valve includes the "AC Option" which includes a rectifier, which converts 24 volt AC to 24 volt DC. We recommend that the Automag zone valve to be installed on a horizontal run of pipe with the zone valve and coil in an upright position.