F23N5/02—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium
F23N5/12—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium using ionisation-sensitive elements, i.e. flame rods
F23N5/126—Systems for controlling combustion using devices responsive to thermal changes or to thermal expansion of a medium using ionisation-sensitive elements, i.e. flame rods using electrical or electromechanical means