My (50 yr old) furnace fan is suddenly always on.
The thermostat fan switch is set to "auto", of course.
And the main burner properly goes on and off as it should - but the fan
just keeps on going and going...
So I'm thinking it's the Honeywell combo fan/limit switch.
I've tried changing its "Off" setting to as low as it goes, but with no
But how to be sure?
How do you test it?