Controls for heating system

Claim 1

For use in a heating system obtaining electrical energy from a suitable source wherein an enclosed region is heated by hot water flowing through a heat exchanger disposed in the region, the hot water being supplied from a boiler heated by a furnace which is electrically actuated and deactuated, the water being circulated between the boiler and the heat exchanger by a circulator pump which is electrically actuated and deactuated, a thermostat being disposed in the space to control the temperature therein and including a first electrical switch which is closed when additional heat must be supplied to the region and which is otherwise open, apparatus comprising: a minimum temperature thermostat for said boiler connected in circuit with the furnace to maintain the temperature of the water in the boiler at a selected minimum temperature, the minimum thermostat including a second electrical switch which is closed when the temperature of the boiler water is below said minimum and which is otherwise open; first means for actuating said furnace and said pump when said first switch is closed and for deactuating the furnace and the pump when the first switch is open; a timer which is automatically reset, said timer when electrically actuated operating for a preselected time period and then is automatically deactuated; second means for actuating said pump and said timer when said first means deactuates said furnace and pump, whereby said pump continues to circulate said water when said first switch is open and said furnace is deactuated while said timer remains actuated; third means for deactuating said pump when said timer is deactuated and said first switch is open; alarm signal producing means; and a comparator coupled between the timer, the second switch and the alarm means to energize the alarm means when the timer is actuated and at the same time the second switch is closed.