We have an old (1930's) blast furnace converted into a gas convection furnace by previous homeowners. No moving parts besides a few valves. Went to turn on the heat this morning and nothing. Normally, we hear a click on the thermostat and a whoosh when the burner kicks in and starts to 'sing'.

I checked voltage all over and it seems all right. Worked fine yesterday. The pilot light is burning away, but that is it.

I was thinking either the old Thermostat is shot or the Relay Switch is.

Anyone have a clue?