Abstract: A gas burner control system for controlling operation of a furnace having a blower fluidically connected to the combustion chamber of the furnace utilizes a mass flow sensor for preventing or discontinuing burner operation in the event of a blower failure or a predetermined degree of blockage in the fluid flow path controlled by the blower. The mass flow sensor includes circuit means which enables use of unmatched sensors, enables establishing of a desired value of temperature difference between sensors, enables establishing a temperature difference that is not constant so as to compensate for different ambient air densities, and enables compensating for voltage variations at different ambient air temperatures.