Rick, good to hear your furnace works in the summer, etc etc,

But Re the switch, what is the obvious problem now, and what is causing it? ?I can imagine many reasons, but perhaps it boils down to opening or closing or both, and just how many times it has been switched under load. ?Like tubes and caps, they only last so long working 12 hour shifts.?

So use the wall switch or some other switch, or just Marr/Marrette two wires together [with gloves on]. With the latter you can see up close what is going on.? While you are thinking about the “switch”, use your back-up brain to ask the transformer how it feels about the situation going on right next door. Maybe it cannot take this kind of life for long either. You know it thongs sometimes due to saturation causing magnetostriction, but insulation breakdown does not have a voice, just an eventual aroma when it is too late. ?So if the switch is bad, what are its ratings? Ya, all hidden from day 1 no doubt. ?Can it be changed?, likely a real tough project???. I still don’t know what it physically really is, let alone its electrical properties, nobody really knows I guess. ?

If the thing is bad, what kind of voltage is it sending to the transformer, during make and during break ? … I’m just asking!! Again likely

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