Patent ID: 6230979
Filing Date: 2001-05-15
Classification: F23N,G05D

Abstract:
A method of controlling a two stage furnace comprising:(a) initiating a second stage delay timer;(b) determining whether there is a call for first stage heat from a thermostat, and if there is not returning to step (a), and if there is, actuating the first stage heating;(c) determining whether there is call for second stage heat from the thermostat, and if there is actuating second stage heating and returning to step (a), and if there is not, determining whether the thermostat is a one stage or a two stage thermostat, and if the thermostat is determined to be a two stage thermostat deactivating second stage heating and returning to step (a), and if the thermostat is determined to be a one stage thermostat, decrementing the second stage delay timer; and(d) determining whether there is time remaining in the second stage delay timer, and if not, activating the second stage heating, and if so deactivating the second stage heating, and returning to step (a).