Hey there im working on an older Southbend steam kettle (KSLG-40e) and im completely mystified as to how this flame sensor works. It uses a Honeywell electronic ignition system and there is no detectible flame sensor or thermocouple. I spoke with a tech at Southbend and he told me to check the millivolts on the ground wire of the ignition module which grounds to the gas valve.
The only wire running to the pilot/ignitor is the ignitor wire and there are no other sensors. The only explanation the tech gave me was "dissimilar metals". I understand the whole dissimilar metals issue what i dont understand is how the gas valve generates the needed millivolts for the Honeywell to detect the flame with no connection other than the pilot light tube.
Thanks for any clarification you can offer.