Patent ID: 7695273

Claim:
A method of controlling a furnace, the method comprising: instituting a combustion cycle; sensing a pollutant concentration of combustion gases produced by the furnace; disabling the furnace when the pollutant concentration reaches a pollutant threshold, wherein the pollutant concentration is related to an average pollutant concentration in the home based on one or more of a size of the home, an infiltration rate of pollutant into the home, a time period delay for the pollutant sensor to open after the pollutant concentration reaches the pollutant threshold, a time period delay for the pollutant sensor to close after the pollutant concentration falls below the pollutant threshold, and a size or operation characteristics of the furnace; enabling the furnace when the pollutant concentration falls below the pollutant threshold; disabling the furnace for a lockout period if the furnace is disabled a threshold number of times; and reinstituting the combustion cycle after the furnace has been disabled for the lockout period.