Safety control for furnace burner

Abstract

A burner cut-out safety control for a combustion heating device having an automatic exhaust flue damper. The safety controls act to discontinue burner operation in the event the damper actuator device or controls fail, or other flue blockage causes products of combustion to be exhausted through the draft diverter inlet opening. The control is integrated with an existing burner pilot safety circuit and pilot valve to cause the pilot valve to be closed in the event combustion gases begin to pass out of the flue through the draft diverter inlet opening, this condition being detected by a lineal temperature sensor extending about the draft diverter inlet opening, which senses combustion gas spillage by the resultant heating of any portion of the lineal temperature sensor. The lineal temperature sensor is placed in series with the pilot burner ignition temperature sensor to cause closing of the pilot valve, located ahead of the main gas valve activated by the burner controls during normal automatic operation of the burner. The fuel supply is thus cut off even if the main gas valve fails. A second temperature sensor is located in the plenum of the warm air ducting as a secondary safety control feature also acting to cause the pilot valve to close in the event of an excessive temperature being sensed in the warm air plenum.

Dependencies are inferred from the claim text.