Patent ID: 8070481

Claim:
A method of operating a combustion appliance that includes a variable speed combustion blower and a pressure switch, the method comprising: determining an expected combustion blower speed at which the pressure switch is expected to change state, including the steps of: increasing the blower speed until the pressure switch changes state; and once the pressure switch changes state, decreasing the blower speed until the pressure switch changes state again; detecting, during operation of a combustion cycle, that the pressure switch does not change state at the expected combustion blower speed; after detecting that the pressure switch does not change state at the expected combustion blower speed, temporarily adjusting the expected combustion blower speed to a temporary combustion blower speed at which the pressure switch changes state; operating the combustion appliance using the temporary combustion blower speed; and repeating the detecting, temporary adjusting and operating steps during a subsequent combustion cycle of the combustion appliance as necessary to respond to transient changes in one or more operating conditions of the combustion appliance.