On Sun, 17 Oct 2010 17:50:34 -0400, Frank
wrote:

On 10/17/2010 5:11 PM, hr(bob) wrote:
On Oct 17, 11:00 am, wrote:
On 10/17/2010 1:12 AM, 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.

Thanks.

I believe mine runs at two speeds, high and low.
Wife is constantly complaining that it is not as warm even though
thermostat is constant, you just don't get that blast of warm air.
Told her she is welcome to turn up the heat but at $3+ per gallon she is
reticent to do so - Hide quoted text -

- Show quoted text -

Running continuously does use some electricity, but it probably
cheaper than spurts of high speed whenever the plenum temperature is
above the preset turn-on temperature. Due to the eveness of the
temperature, you can proably set the thermostat a couple of degrees
coller than normal (for wintertime use) because you won't have the
temperature swings that you get with an off-on type of operation.

Can't remember where we set it with old furnace but when wife is cold
she nudges it up. Furnace or fan does not run continuously.

I've heard similar complaints about heat pumps that don't put out a
burst of heat but give even temperature control.

That's different though. A heat pump can't put out that much heat.
So I gather they run all the time when it's pretty cold, so I guess
they have to run the fan too.

An oil furnace can put out plenty of heat, and even if the temp rises
and falls, that don't bother me**. My main concern is if I can set
the fan to go on only when the furnace is running (not counting that
it starts late and stops late even now, based on I guess what hr said,
plenum temperature). I want to be able to do that.

Do furnaces with ECM allow that? Because there are still plenty of
oil furnaces sold that DON'T have ECM.

Thanks.

I can't ask the manufacturer easily because I haven't picked out
either a furnace company or a furnace, and some salesmen will just say
"Sure".

**The temp rise and fall is like a compresed version of the seasons!