A method and apparatus for controlling the normal operation of a hydronic
heating system, (including AC powered, gas-burning hot water boiler, multi-zone systems) using a DC power source, such as battery power, as the primary continuous source of
electricity. Control functions minimize the consumption of
electric power during normal operation, and eliminate standby
electric consumption in order to extend the life of the batteries and maximize the run-time of the
heating system. A
DC to DC converter supplies
low voltage DC power to the zone thermostats, and also supplies the proper
voltage through zone relays to operate DC zone pumps. By allowing the use of DC power for the thermostats and zone pumps, the
system eliminates the need for transformers, zone valves, and AC circulators, resulting in a large savings in electrical consumption and the
elimination of the standby electric demand ("phantom load") common in conventional hydronic heating systems. A DC to AC
inverter is dedicated to supply
AC power for a hydronic (hot water) boiler. The
inverter is switched on by relays only when needed, thereby eliminating the "phantom electric load" consumed by most boilers when standing by. A time
delay relay circuit allows the boiler to go through its proper shutdown sequence before power is removed. This
control system does not require any internal modification to the other
heating system components.