On Monday, December 11, 2017 at 9:17:17 PM UTC-5, micky wrote:
In alt.home.repair, on Mon, 11 Dec 2017 16:28:52 -0800 (PST), trader_4
wrote:


Even if you're right, yes and no. He gave my neighbor N the impression
that it was the grey controller box, and the limit and the fan and limit
switch is elsewhere. not in something that is called a controller.

That's true for sure if it's a very old furnace. IDK exactly when they
moved away from the temp switches and went to other control methods.
Do you know for sure what it has or doesn't have?

Yes. I forgot that the fan and limit switch could keep the fan on, but
I didn't forget it existed.

I would think furnaces
even 20+ years ago could rely on a controller as part of what makes
turns the fan on and off.

It's 38 years old.

Probably time for a new one. I saw my bills cut in half going from
one that was 25 years old to a new one. That was gas, with oil, the
fuel cost savings in dollars is more substantial and they payback
time would be reasonable.