A signal conditioner for use with a controller and a burner receives an input signal from the controller. A conversion circuit generates a primary output signal corresponding to the input signal to control the burner. The signal conditioner also includes a delay circuit. The delay circuit overrides the primary output signal generated by the conversion circuit and substitutes a delay signal to the burner at a predetermined level for a predetermined time. The signal conditioner may also include a temperature override circuit, which receives a temperature of air from the burner. If the temperature is above or below established limits, the temperature override circuit substitutes a temperature override signal to the burner.