Chimney Damper

[Chris-PA]

Are you serious??

Colder temps mean more wood, more often, to keep the stove temperature high enough to maintain the temperature of the space it is heating... if we had identical stoves, heating identical space, on average my stove would need to generate 21% more heat than yours at all times (because we're talking average). But in reality, during the colder parts of the day it could be as much as 40% more (maybe more depending on wind), especially as the cold snap lingers for days. And because our days warm-up slower, and cool down faster (because of the geography), I need the higher stove temperatures for a greater portion of the day.

More wood, more often, means more coal build-up at a faster rate... until there ain't any more space to add wood in the firebox, forcing the removal and tossing out of all that potential heat just to make room for more wood. During warmer periods those coals will provide enough heat to maintain heating space temperature IF you babysit the stove and keep stirring/raking the coals so air can get to them... but not when it's cold and remains that way for days. Not to mention the heat being wasted out the flue because the stove is running wide open (yeah I'm heating the whole house, but it's a small house and well under the square footage rating of the stove).
IF air came in under the coals burning on a grate (like every other wood-fired appliance I've ever had, seen or used) I could damp-down and those coals would remain screamin' hot for hours... I wouldn't need to stir coals every hour, or add more firewood every 2-3 hours when it's arctic cold... which just builds up the coal bed (which eventually gets wasted during real cold times).

The stove "functions" just as it is designed to do, it reduces emissions... the design just ain't worth a crap for serious heating. There ain't no free-lunch in this life; to gain something you must always give-up something. That's just the way it is, always has been, and always will be. This belief that combustion efficiency equals heating efficiency is pure propaganda. Like I've said before, my 4x4 V8 pickup will get 50 miles per gallon if I drive it 10 MPH!

I thought it was obvious that colder climes would need more capacity, but that was not the discussion. Not all of us are having such a problem with build up of coals in these types of stoves. Perhaps it is just a poor design, and/or perhaps it is too small - i.e. you need more output from it than it can provide, so you are putting more wood in it more often.

Another way of looking at it - these things can give an extra 50% of output when the secondary combustion is cranking in comparison to a traditional stove of similar size. You are comparing the performance of a larger traditional stove that can put out that amount of heat to one that only does it when the secondary combustion is going, so naturally when the volatiles burn off the output will be reduced.

Basically your complaint is that once the secondary burn is reduced the output is insufficient. Get a bigger stove. Then you can have output and efficiency.

 

[Whitespider]

True spider man. But I'm pretty sure the smoke dragon does the same thing when burning in cold weather. Coal buildup is a bugger with either stove.

Yeah, the old smoke dragon would burn into a deep coal bed, but the difference was that coal bed burned many times HOTTER... because air could get under and up through the coals. I didn't need to stir them, or add more wood to them to keep it heating. I didn't have to babysit the damn thing... load it, set it, and walk away for 6-10 hours while it cranked out the heat.

 

[Whitespider]

I thought it was obvious that colder climes would need more capacity, but that was not the discussion. Not all of us are having such a problem with build up of coals in these types of stoves. Perhaps it is just a poor design, and/or perhaps it is too small - i.e. you need more output from it than it can provide, so you are putting more wood in it more often.

Of course that’s the discussion… when I need to burn more wood that’s when the coals build up. I’ve been saying all along it’s a poor design. Yeah I need more output… from the coal bed… which I’m not getting because of the poor design (i.e. no air under it). And “perhaps” you’re not having the problem because you don’t live in as cold of a climat as I am right now.

Another way of looking at it - these things can give an extra 50% of output when the secondary combustion is cranking in comparison to a traditional stove of similar size. You are comparing the performance of a larger traditional stove that can put out that amount of heat to one that only does it when the secondary combustion is going, so naturally when the volatiles burn off the output will be reduced.

Basically your complaint is that once the secondary burn is reduced the output is insufficient. Get a bigger stove. Then you can have output and efficiency.

I’ve already said, several times, this EPA stove puts out way more heat when the secondary is burning, but it’s short-lived and ain’t enough to off-set the drop and temperature when the secondary it shuts down (because with no air under the fire it cannot make efficient use of the coal bed).
And I am comparing stoves “of similar size”. Compared to the old smoke dragon the fire box width is near identical (actually the new one is wider now that I removed some firebrick, maybe an inch) and the height is just a tad shorter (maybe an inch). The old smoke dragon was deeper, but I used the same length firewood (16-inches). The outside surface area inside the plenum is larger on the new one (I have the sides, back, and top enclosed… only had the two sides and top enclosed on the dragon). Fuel load is about the same when loading a cold, clean stove (i.e. full arm-load plus a little more). The new one weighs at least 200 lbs more than the dragon did… maybe over 250 more (I could carry the old one myself… it was my limit, but I could do it… I carried it up the steps and out of the house when I replaced it with what I have now).

What you’re saying does not add up. If these things are such damn efficient heaters… why do I need a larger stove, with more capacity than I had before?? If these things are such damn efficient heaters… shouldn’t I even be able to go to a smaller stove, with less capacity do what the old one did??

 

[Chris-PA]

I was not particularly talking about physical size, rather btu output. When the secondary combustion is going it has enough output and is more efficient. When the secondary combustion stops it has lower output, apparently not enough for your needs. You want more output, so you need a higher output capacity stove. If you don't care about efficiency then get a smoke dragon that has a higher output.

It also sounds like your stove does not work very well - it's likely there are better and worse designs. But it is also modified. The secondary combustion on mine goes quite a long time and the output is usually far more than I want, but even after that dies down the coals are still cranking out the heat and will burn up quite completely. Large masonry structures around our stove store the excess heat during high secondary burn so the temperature does not vary as much. Yours is incorporated into a furnace with air blowing over it continually, so you need higher instantaneous output all the time.

Your main beef appears to be about output capacity, combined with some design problems of that particular stove.

 

[Jredsjeep]

its getting hot in here, like a mentioned not all stoves are the same and even the same stove in a differant house will perform differantly. spidey i lurk a bit and usually enjoy the meticulous way you can pick apart problems. i have to do that sort of thing at work although you are probably better at it.

the temps are a little colder your way but i am not seeing a huge shift. i am a firm believer the wind can make a huge differance. i am in a hilly section so we have nice windbreaks and do not get as much in general but when we do the draft pulls hard and its much more to heat my house (both in wood use and fighting heat loss). i am just speaking from what i have known and used. my EPA stove heats far better, hotter and longer than my old stove. i have an Englander 30 now vs an old simple box stove (cant remember brand anymore) before so i was a big step up in general. i know my stove is not a high dollar stove, i got it on sale from a box store (way before i knew this place) but it has served me very well for the past 8-9 years. my oil furnace has not fired off in years.

coal build up has not really been a problem for me though even with no air from underneath. i have a roughly 900sqft ranch that was built in the 40's, i have updated the windows and some walls but the rest of the house is insolation free. the attach has sawdust for insolation, i need to take care of that........but like a said my stove uses half the wood my box stove did and i get twice the heat.

i am sure some of the old smoke dragons were not that bad and some of the new stoves are probubly not that great. sounde like you might have pulled that unlucky card.

 

[Jredsjeep]

It also sounds like your stove does not work very well - it's likely there are better and worse designs. But it is also modified. The secondary combustion on mine goes quite a long time and the output is usually far more than I want, but even after that dies down the coals are still cranking out the heat and will burn up quite completely. Large masonry structures around our stove store the excess heat during high secondary burn so the temperature does not vary as much. Yours is incorporated into a furnace with air blowing over it continually, so you need higher instantaneous output all the time.

.

i have noticed that to be huge help in cutting down the temp swings. i built a nice base and full wall backer out of recovered bricks from an old farm house. looks nice, safer and balances out the heat much better.

 

[Whitespider]

I find it hard to believe the old steel and cast box I had before was rated anywhere near the 72,000 BTU/82.6% efficiency of the
Pacific Energy Spectrum
I have now…

 

[Wazzu]

I agree with pretty much all your observations whitespider. I have tons of coals out in the back part of my lot that I have to throw out there so I can get enough room in the firebox for a new load. My experiences with older air tight stoves like non-epa blaze kings and earth stoves are much better than with my pacific energy. Most of those older ones were good as long as you kept the thermostat in working order. When the wood was done being burned you didnt have an 8 inch deep coal bed to contend with, just fluffy ashes. I think the best epa option out there has to be the newer blaze kings because they automatically open the damper as they cool down, therefore burning down the coals. The problem is that they cost so damn much. I guess you get what you pay for or something. I have pretty much decided that my insert is basically a weekend warrior type of stove. It is simply not designed for full time/primary use heating duty.

 

[Chris-PA]

I find it hard to believe the old steel and cast box I had before was rated anywhere near the 72,000 BTU/82.6% efficiency of the
Pacific Energy Spectrum
I have now…

OK, from the manual:

<blockquote>Above fire secondary air injection:
The hollow "air baffle" injects super-heated sec-
ondary air just above the load. With the stove
at the proper operating temperature, this will
create a secondary flame that will be evident for
approximately 1/3 of the total burn time.</blockquote>

Obviously after the secondary burn the instantaneous output is not enough for your needs, given the outside temperatures, lack of thermal mass and the expectation of maintaining a constant house temperature. Hence my comment about it not being big enough. An empty box with a grate and airflow from below will allow the logs from the previous load to be incinerated faster, with a high peak output, making room for you to load more wood. As it is you are trying to reload before the intended burn cycle is complete, so yeah, there's still too many coals left.

Further, it was not designed to be mounted in an airstream as part of a furnace. As a freestanding woodstove it was intended to emit a large portion of heat in radiative form, whereas you need all of the output to be convective. It was not designed or optimized for that and you may well be reducing the firebox temperature or some such. It is not valid to condemn the design of all "epa" secondary combustion stoves based on the shortcomings of your not-designed system. Just because that does not perform as you would like does not mean there is anything wrong with the pieces you used.

 

[Ayatollah]

What you’re saying does not add up. If these things are such damn efficient heaters… why do I need a larger stove, with more capacity than I had before?? If these things are such damn efficient heaters… shouldn’t I even be able to go to a smaller stove, with less capacity do what the old one did??

I think they are efficient burners, but not necessarily efficient heaters. You get more carbons burned per cord. Their efficiency rating is not BTU's per cord, but how efficiently they burn up all the material and not spit out carbon. Remember when the first generation of smog control devices on the old cars came out? They impoved the condition of the exhaust, but didn't make the car run any better. Actually, I think the cars ran worse for quite a while.

 

[gregfox]

You guy's hijacked the damper thread!!! And now back to spiderman's pizzed at himself for the stove(ace) he picked!!! Spidey, buy another smoke dragon like you had, make your own, or buy something designed for your application. Epa, shmeePA, I don't care how much smoke you make(or blow), do what you need to make your house comfortable and yourself happy in the process!!!

 

[Ayatollah]

You guy's hijacked the damper thread!!!!

A slight deviation in the flight plan. Nobody got hurt,

 

[chadihman]

Ok, back on track now. Most epa stoves dont want a damper installed. I went through a lengthly dispute with a stove company about my previous new cast iron epa stove. I't would reach really high temps and burn the wood up fast. The stove company asked many questions about my chimney set up. I ended up buying a damper and a draft meter. I would adjust the damper to controll the draft to the manufactures draft spec. My pipe was a little on the strong side but I could easily adjust the damper to get the draft in range. Still the stove would burn too hot and to fast. I found a leak in the stove at the bottom at a joint. I did the candle flame test and the flame sucked right into the joint. I took many pics of the flame pulling,damper setting and draft readings and emailed them to the company rep. Now I have the warranty replacement of a different model steel stove and it works perfectly without a damper.
A damper in a epa stove is a good idea only if you have an extra stong draft. Install a draft meter so you know where to adjust the damper to. More air is being pulled into a stove with a strong draft. Epa stoves can only adjust the air so far closed and cannot be sealed. Secondary air tubes get air all the time with no adjustment on the air. An adjustable secondary burn tube air adjustment would be something that I might ad to my stove. I could close the air to the burn tubes and then have more air rushing in at primary air intake and startup air that injects the air at rear and front bottom. This would help burn the coals faster.

 

[Chris-PA]

Ok, back on track now. Most epa stoves dont want a damper installed. I went through a lengthly dispute with a stove company about my previous new cast iron epa stove. I't would reach really high temps and burn the wood up fast. The stove company asked many questions about my chimney set up. I ended up buying a damper and a draft meter. I would adjust the damper to controll the draft to the manufactures draft spec. My pipe was a little on the strong side but I could easily adjust the damper to get the draft in range. Still the stove would burn too hot and to fast. I found a leak in the stove at the bottom at a joint. I did the candle flame test and the flame sucked right into the joint. I took many pics of the flame pulling,damper setting and draft readings and emailed them to the company rep. Now I have the warranty replacement of a different model steel stove and it works perfectly without a damper.
A damper in a epa stove is a good idea only if you have an extra stong draft. Install a draft meter so you know where to adjust the damper to. More air is being pulled into a stove with a strong draft. Epa stoves can only adjust the air so far closed and cannot be sealed. Secondary air tubes get air all the time with no adjustment on the air. An adjustable secondary burn tube air adjustment would be something that I might ad to my stove. I could close the air to the burn tubes and then have more air rushing in at primary air intake and startup air that injects the air at rear and front bottom. This would help burn the coals faster.

Again, it's partly about how the air control works on your particular stove. I have the Magnolia on a 28' flue that draws very well, but the air control on that stove limits both primary and secondary air. And I can pretty much shut it down with the air control.

My little Hampton H200 is upstairs on a shorter flue, and its air control limits only primary air. If the Magnolia in the basement worked that way I would have a problem, as I need to limit both to keep it under control. There are times when that thing is stopped down so hard there is only but a small opening letting any air in - you can see every little little spot around the door glass where a few molecules of air may be getting past - there is no way a damper in a stove pipe is going to stop the airflow down that far, so it would effectively do nothing under those conditions. An area reduction in the flue is irrelevant unless there is air flow and it is more restrictive than the inlet opening. And if you make it more restrictive than the inlet then smoke will go the other way.

 

[Whitespider]

Obviously after the secondary burn the instantaneous output is not enough for your needs, given the outside temperatures, lack of thermal mass and the expectation of maintaining a constant house temperature. Hence my comment about it not being big enough. An empty box with a grate and airflow from below will allow the logs from the previous load to be incinerated faster, with a high peak output, making room for you to load more wood. As it is you are trying to reload before the intended burn cycle is complete, so yeah, there's still too many coals left.

So you’re say the same thing I’ve been saying… it’s an efficient combustor, but a horribly inefficient heater. And how can lack of mass be part of the problem when I managed to make it a better heater by removing some of it, and the old stove had virtually none?

Further, it was not designed to be mounted in an airstream as part of a furnace. As a freestanding woodstove it was intended to emit a large portion of heat in radiative form, whereas you need all of the output to be convective. It was not designed or optimized for that and you may well be reducing the firebox temperature or some such. It is not valid to condemn the design of all "epa" secondary combustion stoves based on the shortcomings of your not-designed system. Just because that does not perform as you would like does not mean there is anything wrong with the pieces you used.

Whatever… that don’t add up. All radiated heat must be converted into conductive heat or it will never warm the air. Radiated heat travels through the air without warming it until it strikes a solid surface; the solid surface absorbs the heat radiation and transmits it to the air via conduction. Any and all woodstoves (or furnaces) emit heat by both radiation and conduction; if you increase the conduction (say by placing a fan behind it) you reduce the radiation proportionally… but the total amount of BTU’s remain the same, it does not, can not, change. It does not matter where the conduction takes place, whether at the firebox surface or at some point across the room… it may “feel” different to the body, but the thermometer will see it in the same way because the total “amount” of heat does not change. It’s a simple law of physics; energy (in this case heat) can be neither created nor destroyed, it can only change form and/or location. Because I am doing nothing to change the “form”, the energy (heat) can only change location (i.e. move from the firebox surface to the living space via forced air). Admittedly some of the heat is lost in the basement due to radiation… but not near as much as was lost from the old dragon. The basement was much warmer before (as was the upstairs)… again, maybe the dragon was a less efficient combustor, but far-and-away a more efficient heater using the same quantity of fuel!!! And you see, that’s where all of your arguments, excuses and rationalizations fall short… using the same quantity of fuel!!! Using the same quantity of fuel, the dragon did a better job of actually heating, while at the same time completely consuming the fuel load over a half dozen or so hours, instead of over two dozen or more hours… it just flat is-what-it-is! The new-fangled stove of the same size, using the same fuel load, may (or may not) put out more total BTU’s over the complete burn cycle, but at a greatly reduced per-hour rate (average)… and no matter how you slice it, that makes it a less efficient heater. It just flat is-what-it-is!

 

[Chris-PA]

So you’re say the same thing I’ve been saying… it’s an efficient combustor, but a horribly inefficient heater. And how can lack of mass be part of the problem when I managed to make it a better heater by removing some of it, and the old stove had virtually none?


Whatever… that don’t add up. All radiated heat must be converted into conductive heat or it will never warm the air. Radiated heat travels through the air without warming it until it strikes a solid surface; the solid surface absorbs the heat radiation and transmits it to the air via conduction. Any and all woodstoves (or furnaces) emit heat by both radiation and conduction; if you increase the conduction (say by placing a fan behind it) you reduce the radiation proportionally… but the total amount of BTU’s remain the same, it does not, can not, change. It does not matter where the conduction takes place, whether at the firebox surface or at some point across the room… it may “feel” different to the body, but the thermometer will see it in the same way because the total “amount” of heat does not change. It’s a simple law of physics; energy (in this case heat) can be neither created nor destroyed, it can only change form and/or location. Because I am doing nothing to change the “form”, the energy (heat) can only change location (i.e. move from the firebox surface to the living space via forced air). Admittedly some of the heat is lost in the basement due to radiation… but not near as much as was lost from the old dragon. The basement was much warmer before (as was the upstairs)… again, maybe the dragon was a less efficient combustor, but far-and-away a more efficient heater using the same quantity of fuel!!! And you see, that’s where all of your arguments, excuses and rationalizations fall short… using the same quantity of fuel!!! Using the same quantity of fuel, the dragon did a better job of actually heating, while at the same time completely consuming the fuel load over a half dozen or so hours, instead of over two dozen or more hours… it just flat is-what-it-is! The new-fangled stove of the same size, using the same fuel load, may (or may not) put out more total BTU’s over the complete burn cycle, but at a greatly reduced per-hour rate (average)… and no matter how you slice it, that makes it a less efficient heater. It just flat is-what-it-is!

And here is what you said before:

"It-is-what-it-is… the EPA fireboxes must pass emissions first, heat second. The efficiency rating is based on how much heat is lost through the flue… it has absolutely nothing to do with how efficiently they heat your home. What’s gonna’ keep you warmer from 25 pounds of firewood? An 85% efficiency over 18 hours to completely consume the fuel load, or 60% efficiency over 6 hours to completely consume the fuel load? Less wood/more heat is deception without actually lying… I base efficiency on how warm I am, not by what’s exiting the flue. "

So which is it - are you using the same amount of firewood or 3 time less like you said previously? It is pointless to have a technical discussion with someone who changes what data they are presenting.

 

[Whitespider]

Where, exactly, did I say I was using 3 times less wood??
Or even more to the point... Where, exactly, did I say I was using 3 times less wood to achieve the same level of heating efficiency??
Heck, if I had to guess, I'd say I'm using about the same amount of wood, with more messing around with the firebox, while trowing out more potential heat (waste), to achieve a lower level of heating efficiency...