Patent ID: 7261061

Claim:
A water heater comprising: a water container; a combustion chamber adjacent the water container; a main burner associated with the combustion chamber and arranged to combust fuel to heat water in said water container, said burner comprising a plenum chamber having a combustion surface and a fuel/air conduit extending from the plenum chamber adapted to receive fuel and air; a pilot burner that receives fuel directly from a fuel conduit and produces heat positioned adjacent the combustion surface; and means for collecting contaminants from fuel and/or air flowing to the pilot burner such that collection of a selected amount of the contaminants reduces the flow of the air and/or fuel, thereby reducing production of the heat and shutting off the main burner; wherein the flow of the fuel and/or air to the pilot burner is at a rate that substantially corresponds to a rate of collection of contaminants on the combustion surface that results in production of CO by the main burner at a selected level.