The furnace in this house has gone thru several owners with their set of tools. The last owner gave up on rewiring and left it in a rat's nest for me. Nothing was connected when I opened the panel. It's a two burner up flow with a fan limit control made by Wards. It is now wired and working. With the Heat set to come on, the gas ignites to warm the heat exchanger before the blower comes on. I can also wire the fan to come on the same time the thermostat calls for the flame to ignite. Each way the fan stays on when the exchanger is hot but what way is correct?

Heating & Cooling - Montgomery Ward - (223600UP) Heater