Patent ID: 8201750
Filing Date: 2012-06-19
Classification: F24D

Abstract:
1. An electronic circuit to conserve fuel consumption and reduce carbon dioxide emissions in a heating system that comprises a boiler that heats water, the boiler comprising a burner and a heat exchanger with a water inlet and a water outlet; a water pump powered by an electrical supply; and, a room thermostat comprising a setting for a lower temperature limit and an upper temperature limit wherein the room thermostat is operable to activate the burner upon detecting a room temperature at or below the lower temperature limit and deactivate the burner upon detecting a room temperature at or above the upper temperature limit, the electronic circuit comprising: an override thermostat comprising a setting for a lower temperature limit and an upper temperature limit below the respective lower temperature limit and upper temperature limit of the room thermostat and operable to activate continuous operation of the burner when the room temperature falls below the lower temperature limit of the override thermostat and until the upper temperature limit of the override thermostat is reached; a timer operable to deactivate and reactivate the burner while the room thermostat is calling for heat; a differential temperature switch configured to disconnect the electrical supply to the water pump when the difference in water temperature between the water inlet of the heat exchanger and the water outlet of the heat exchanger falls below an adjustable set point; and a temperature switch configured to prevent operability of the timer until the temperature of the water at the water outlet of the heat exchanger rises above an adjustable set point.