Furnace fan slow to turn on, off
We recently (as in last week) purchased a cabin equipped with a Day and Night forced air furnace. The fan for the furnace seems to take an awful long time to come on after the burner assembly ignites, and, similarly, the fan takes an awful long time to turn off after the furnace is turned off. It's making me nervous, so I wired a jumper at the thermostat so that, for now, the fan comes on immediately when the furnace starts.
I'm having trouble finding any information about this furnace (Day and Night), so I'm trying this forum for pointers on where I should look for a problem (or is there perhaps an adjustment to be made). Limit switch or fan delay timer relay? I could use a tutorial on principle of operation; I've never worked on a furnace before. Sorry, I don't have the model number; all I can say right now (until our next trip to the cabin) is that it was made somewhere between 1969 and 1983, and it has electronic ignition.
Thanks for any help!