On Sun, 17 Oct 2010 09:06:26 -0500, Rick Brandt
wrote:

mm wrote:

Do low-speed fans on new warm air oil furnaces run all the time?

How do multii-speed fans in new OIL warm air furnaces work. One
webpage said that such a fan might use 200 watts, but the one speed
fan my current furnace has might use 800 watts! That seems amazing.

It also gave the impression that when the furnace calls for the low
speed fan, it's because the fan runs all the time. Is that right?


I'm used to the idea that very few oil furnaces have efficiency 90% or
greater, and that they are very expensive. But if I get a
electronically controlled fan with the furnace, that part of the
furnace is eligible for the Federal Energy Credit, and I presume it's
something I want to have anyhow. But I'd like to know how it works
before I buy one.

Our furnace has a continuously variable DC fan that is (as far as I know)
always running. You set your thermostat fan control to "ON" and the
computer manages the speed.

Does that mean if you set it to auto, it would go off when the furnace
isn't running? I like the feature you describe if I'm not stuck using
it when I don't want to.

When not calling for heating or cooling the fan runs very slowly. You might
feel a slight draft from the vent, but you could never hear it running.

I'm afraid I might. It is a straight shot from the furnace to the big
vent in the hall right outside the bedroom door, and the noise of my
current fan has been a big problem. I tried changing the fixed speed
on my fan, by connecting different wires, but as the schematic said,
it was already on the lowest speed. I have to shut the door when I'm
sleeping or trying to get to sleep.

This was explained as helping to "even out" the temperatures within the
home.

If my temps are uneven, I either don't notice or don't mind.

Thanks to everyone including you, Dufas, and clare.