The Zone Valve Control 304V connects up to four thermostats and operates zone valves to provide heating to a zoned hydronic heating system. The 304V operates a system pump whenever a zone valve opens. Zone 1 can operate either a zone valve or a circulator to provide heat to an indirect domestic hot water tank with optional priority over zones 2 through 4. The 304V includes optional exercising to prevent circulator seizure when not in use, and optional post purge operation of the domestic hot water tank to maximize energy savings. The 304V provides a RoomResponse (TM) signal to modulating-condensing boilers to optimize comfort while improving boiler efficiency.