Stopping down the air inlet on my wood stove?


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Old 11-04-16, 12:32 PM
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Stopping down the air inlet on my wood stove?

I have a Napoleon wood stove. It produces a lot of heat, even with the air inlet stopped down all the way. Except on really cold days, it just makes the house too hot, so we rarely use it. There is a big glass door and the flames are pretty; we would like to use it more.

It would be easy enough to stop it down further, but the manufacturer says it will then violate EPA regulations. We are in the middle of nowhere, I can't see that a little more pollution is going to hurt anything; but I surely don't want to coat the inside of the chimney pipe with something that will catch on fire.

Any advice for me about this dilemma?
 
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Old 11-04-16, 12:36 PM
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OK, I have no experience in this type of thing and I'm responding more for the opportunity to learn. So my comment is...will using less wood or fuel make a difference? Is there no damper or flue type baffle that can be adjusted to let out more heat through the stack?
 
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Old 11-04-16, 01:03 PM
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A slower burn will put out less heat but create more creosote/soot. Letting the fire all but go out before you add wood should also help. I clean my chimney flue every month during the winter.
 
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Old 11-04-16, 01:16 PM
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You clean it monthly? Do you generally have a fire going all the time?

I have had maybe 6 fires in 4 years; the previous owner was never here in the winter, so I doubt he has any in his 6 years. I am hoping that is not enough usage to require a cleaning.
At my old house I had maybe 10 fires a year in the fireplace and cleaned it every 10 years. They never commented about it being particularly dirty.
 
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Old 11-04-16, 01:42 PM
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A lot depends on the weather but I prefer to heat with wood ... my wife prefers the heat pump
I'll often let the fire smolder during the day and fuel it up come dark. If you have a fire more days than not and utilize a slow burn - the flue needs cleaning every month or so. A hot fire burns cleaner and won't give as much soot build up. In my shop if I have a fire in the stove it's a hot fire and even though I mostly burn pine and trashy wood in the shop stove - that flue rarely needs cleaning.

It's hard to say how often a particular flue needs cleaning as a lot depends on how it's used. If you don't mind getting on the roof and looking down the flue with a flashlight every so often you'll get a good idea of how often it should be cleaned.
 
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Old 11-04-16, 03:48 PM
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In an ideal world you would get a stove sized more appropriately for your needs (smaller). There is only so much you can choke down a stove before you're making more smoke than flame. Better would be a small stove you can run in it's sweet spot and you'd get the pretty flame you want without cooking you out of the house.
 
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Old 11-04-16, 04:09 PM
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No damper in the chimney pipe?
 
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Old 11-04-16, 04:22 PM
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I did a quick search to get a look at a Napoleon wood stove. The ones I looked at had a single lever in front to control both primary and secondary air.

Now, my old Dover used two eyes in front to control intake but also used a damper in the stove pipe. Since the draft from the chimney can vary from one installation to another I see no problem with a damper in your stove pipe to slow the burn process. I now have a Regency wood stove with the glass door and the single damper on the intake can shut the fire almost off. But when I do I lose the pretty view and the glass soots up, so I don't shut it down that much. If your unit is working properly, not providing a lot more air than intended, then IMO, it is simple pulling too much intake air.

How tall is your chimney and is it on the inside or outside?

Bud
Also, do you know what size that unit is, small medium, or large?
 

Last edited by Bud9051; 11-04-16 at 04:29 PM. Reason: added question
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Old 11-04-16, 04:23 PM
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My wife wants to pull it out and replace it with a fireplace. I expect I could buy a great car for what that would cost.

There is no damper in the chimney pipe. It is supposed to be air tight and controlled by the air intake.

I've never tried putting in small amounts of wood. That might help, but would require frequent refueling. I suppose I could also turn the heat down a few hours before starting a fire.

Chimney is about 13' to the ceiling and maybe 6' on the roof. Never really measured it, but it is about my height. The roof is like 45 degrees, so I am never going up there...
 
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Old 11-05-16, 03:21 AM
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Do you have a masonry chimney or just stove pipe. If stove pipe is it single or double wall?

Whenever I have a fire in the stove I have the heat pump set back to about 60 so it will only cut on if the fire goes out or almost out.
 
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Old 11-05-16, 04:06 AM
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So, it sounds like most of the chimney is inside the conditioned space and it is a straight shot to the ceiling and out. As Mark asked, is this a metal chimney or masonry on an outside wall?

A picture would help.

Bud
 
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Old 11-05-16, 06:30 AM
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Metal, completely interior.
I have always assumed it was double wall, but don't really know. How would I tell?
 
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Old 11-05-16, 07:34 AM
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I assume your fire control is not able to slow the fire down enough as you stated.
When the air inlet is stopped down all the way there is still some space to allow air to enter, it's not shut off completely. The amount of air entering is a function of the pressure across that opening. The equation for that pressure is P (in pascals) = .007 * delta t * delta h. By installing a damper in the stove pipe you will absorb some of that pressure across the damper and slow the burn rate which will also slightly reduce the flue temperature.

With your chimney all on the inside, except for above the roof, the potential for soot in greatly reduced.

Staying with an air tight wood stove over a fireplace is a huge advantage. Installing a damper to control the draft on your chimney to allow you to control the fire on your current stove is totally acceptable and actually required in some cases (like yours).

Bud
 
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Old 11-05-16, 07:58 AM
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How would installing a damper differ from restricting the air intake? Wouldn't they both reduce the pressure?
 
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Old 11-05-16, 10:26 AM
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Yes, they both work to reduce the intake air flow. But it seems your current control is not sufficient to slow the fire. Even if your stove is their larger model, that only provides a larger fire box to allow a larger fire. It does not limit how small the fire can be, other than perhaps the larger unit doesn't close off the intake as much.

What kind of wood are you burning and how is it split? Smaller pieces will burn more rapidly and hotter. Leaving some round, 6" to 8" range would slow the burning process. How long has your wood been drying? Is your fire raised up out of the ashes with a grate, that would increase the burn rate?

I know, a lot of questions, but we can narrow down your problem and that stove can work just fine for many years.

Bud
 
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Old 11-06-16, 06:34 PM
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The wood is several years old, of various hardwoods. A lot of it is pretty small; branch trimmings or small trees.

Using larger pieces makes sense. I am something of a hoarder, and have more wood than I need; I will make it a point to used the larger pieces.

I appreciate the help.
 
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Old 11-07-16, 03:20 AM
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I use smaller pieces to start the fire but once it's going good I normally stuff big chunks in the stove. They'll burn slower and longer. When the fire is almost out, I'll throw the small stuff back in the stove to get the fire going again.
 
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Old 11-07-16, 12:56 PM
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Heh, heh! A fireplace might produce the opposite problem. You can have a big ROARING fire that will suck out all the heat in a house and leave it cold.

You have a woodstove that provides a lot of heat just when the heat pump is the least efficient.

You need to do some careful thinking about what's important to you.

MOST people would install a high efficiency direct vent gas fireplace that has an attractive flame and turns on and off with a thermostat or wall switch. That would probably make your wife happy.

If you REALLY, REALLY want to heat with wood, you need a properly sized (smaller) wood stove.



You are describing a wood stove that is too large for the space you have. It is properly sized for those "really cold days" and too big for the rest!


A gas furnace turns on and shuts off to match the heat produced with the heat needed to maintain a set temperature, and the furnace can thus match the set tempertaure accurately even in widely varying temperatures.

But that doesn't work as well with a wood stove.

The basic problem is that someone probably bought a stove to have that view of a nice big fire, not realizing that a high efficiency wood stove would produce a LOT of heat!
 
 

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