The Smart Boiler Control 294 provides central and indirect domestic hot water heating or volume domestic hot water heating by operating up to four boilers. This can be expanded in groups of four boilers through the use of expansion controls up to a maximum of sixteen boilers. The 294 operates both condensing and non-condensing boilers that are either modulating, single, two, three or four-stage to provide a flexible, cost effective hybrid boiler plant solution. The Watts(R) OnSite web and mobile applications provide real-time remote monitoring, setting adjustments, and notifications.