Good chance the furnace is faulting. What is the model number?
This unit covered a lot of series. Can you tell me if your unit lights with a glow ignitor or a spark pilot?
So you turn switch off and on, then unit progresses and heats fine....satisfies thermostat, but then will not restart?
Is this the pilot with white yellow and green wires?
Can you tell me if this control is on your furnace?
Some had them while others didnt.
sorry, see if this one comes through
That control is your problem. It is a lockout timer.....but now it is not letting the unit fire up until power removed and restored.