ok, thanks for the reply. It could be a voltage problem. I have watched the voltage at the control as the furnace cycles with a digital voltage meter. I honestly can not see the voltage drop below about 118 and that is during the blower startup surge. Do you think the voltage is sagging faster than can be seen on the digital meter? If it does, will a Ferroresonant transformer change fast enough to solve the problem? The burner will light and burn for maybe 30 seconds, then drop out and relight. thanks for any thoughts you might have.
