US Patent 7553151 Timer relay control board

A heater (12) includes a burner (16), a valve (20), and an inducer (18). A thermostat (24) is electrically coupled to the heater (12) and a control board (44) is disposed in the heater (12) and electrically connected to the thermostat (24). The control board (44) includes an inducer relay (50), a valve relay (52), and a control timer (54) for switching the valve (20) between a high flow stage and a low flow stage and the inducer (18) between a high speed stage and a low speed stage, respectively, wherein the inducer relay (50), the valve relay (52), and the control timer (54) are mounted to the control board (44) to define a singular and compact controller (30).