Furnace monitoring system

Claim 1

A monitoring and display apparatus for use in combination with a heating system of the type having a combustion chamber, adjustable means for supplying air to said combustion chamber to support combustion, an exhaust duct for exhausting combustion products from the combustion chamber, a fuel input nozzle and conduit means connectable to a fuel source for supplying fuel to the combustion chamber, and a heat exchanger in the gas flow path between the combustion chamber and the exhaust duct for heating a fluid medium, the apparatus comprising first and second transducer means for sensing the tempertures at the combustion chamber and the exhaust duct, respectively, and for producing electrical signals representative of said temperature; third transducer means coupled to said conduit means for sensing the rate of flow of fuel to said fuel input nozzle and; logic display means electrically connected to said transducer means for calculating and selectively displaying parameters representative of the operation of said heating system comprising a clock; memory means for storing digital data representative of the temperature and flow rate parameters sensed by said transducers and of preselected limit values for selected ones of said parameters; input means including a keyboard for manually supplying said preselected limit values to said memory means; calculator means responsive to said clock and to the sensed parameters stored in said memory means for calculating fuel usage per unit time and for supplying signal representative thereof to said memory means; and alarm means for periodically comparing said limit values with the sensed parameters and for providing a perceivaable indication when said limit values are exceeded.