Patent ID: 7768410

Claim:
A method of operating a flame sensing system comprising: providing a flame sensing system, the flame sensing system comprising: a signal generator; and a controller; providing a flame excitation signal from the signal generator, the signal having a frequency set at a first frequency; determining at least one characteristic of the flame signal; adjusting the frequency of the flame excitation signal to a next frequency; determining the at least one characteristic of the flame signal at the next frequency; applying a compensated value to the at least one characteristic at the next frequency; comparing the at least one characteristic at the first frequency to the compensated value of the at least one characteristic at the next frequency; storing a change and/or ratio between the at least one characteristic at the first frequency to the compensated value of the at least one characteristic at the next frequency in a memory; and using the controller to control the flame sensing system if the change and/or ratio in the at least one characteristic of the flame signal stored is outside a threshold range.