Hi all. I have an older Osburn woodstove in a mobile home. It draws in fresh air from under the home through the pedestal it sits on. There is a bar under the front of the firebox to control airflow; from no airflow to a full on blaze. I am installing a heat reclaimer this summer. I was debating on putting a damper above the reclaimer thinking that it would keep more heat in the box. My other concern is that the flue above the damper would build up creosote faster due to the cooler exhaust temp. Is this necessary or am I going overboard? Thanks for any help.
Do I need a flue damper?
- Thread starter Finster
- Start date
-
Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.
We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.
We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.
- Status
Grisu
Minister of Fire
Please don't and you already seem to know why. Those devices are perfect creosote factories that can quickly lead to a chimney fire endangering you and your home. Not to mention that cleaning the flue gets a real hassle. Use the stove and its air control to regulate heat output. When run properly you should not lose much heat up the flue and what is lost is required to keep the draft going.
Do you have a need for a higher heat output? Maybe we can help you in getting the most out of your stove. What model from Osburn do you have? How dry is your wood? How tall is the chimney and how has it been constructed? Do you have a stovetop thermometer and what temps do you see during a normal burn?
Thanks for the fast response Grisu. I do not have a need for a higher heat output. I am only trying to utilize some of the heat I am losing up the flue. That's why the heat reclaimer sounds like a good idea. My stove is a model 1050, about 25 years old and works great. I burn Biobricks as my main heat source and seem to go thru 3-4 pallets a season. From the top of the stove to the top of the pipe is approx. 12ft., with 7 ft. being above my ceiling line. I do have a thermometer that I keep about 8'' above the stove. It will usually run at 400 degrees.
If this is in a mobile home I am guessing that it has a relatively short chimney. Putting a heat reclaimer on the stove will further slow down draft which may make it hard for the stove to burn correctly. If you are not getting enough heat, maybe draft is already insufficient? How strong is the secondary burn on this stove? The path to good heat is to have sufficient draft and to burn fully seasoned dry wood.
Thanks for the response begreen. The model stove is made for mobile homes. I'm not sure what secondary burn is but I assume it is the burning of residual gas. I have never had issues with airflow.
Yes, secondary combustion is the burning off of the excess wood gas. It happens at the top of the stove under the baffle as secondary air is introduced through a manifold. To answer the question, no need for a flue damper with this setup, especially with a short chimney.
Grisu
Minister of Fire
Is that a surface thermometer on a single wall pipe? Actual flue temps would then be 1.5 to 2 times as much so 600 to 800 F. A bit on the high side but 8" above the stove is also a bit close. You may get mixed readings from flue and stove. I would put it at least 18" above the stove top to get a better reading of the actual flue temp.
What you actually need is at least 250 F at the top of the chimney to prevent moisture from condensing on the inside of the flue wall. With that short flue and the very dry bricks you are burning you would probably be ok with just 300 F on the flue thermometer if not less. What is your usual air setting? Can you close it all the way down and keep the burn going? A separate thermometer on the stove will tell you how much heat you actually get.
It is a thermometer on the surface of a single wall pipe. Is there a recommended distance that I should put the heat reclaimer above the stove? Also, where should I keep the thermometer after the reclaimer is in. My total flue distance from stove to peak is right around 12' with 7' being double wall. I can add another 3' piece if necessary. I'm only adding this because you said that I had a short flue. Is it better to add more to it? If I close the damper below the stove I can shut off the air supply completely; only glowing coals are left. Thanks again
In case we weren't clear, you should not put the reclaimer on the pipe. Instead, figure out why the flue is running a bit hot. It could be that the stove is not seeing good secondary combustion.
What is the air control usually set to once the bricks are fully aflame?
From the manual:
• Furthermore, installation of a draft damper is not recommended. Indeed, with a controlled combustion wood stove, the draft is regulated upon intake of the combustion air in the stove and not at the exhaust.
What is the air control usually set to once the bricks are fully aflame?
From the manual:
• Furthermore, installation of a draft damper is not recommended. Indeed, with a controlled combustion wood stove, the draft is regulated upon intake of the combustion air in the stove and not at the exhaust.
Last edited:
Grisu
Minister of Fire
At least a mile in either direction.
Seriously, don't put one in. Those contraptions should be banned. At least 18" above the stove but it does not hurt to have it higher.
Double wall or class A? Who installed the chimney? When you only have glowing coals when closing the air fully but no flames I have the feeling your draft is insufficient. 12 ft may not be enough. Try adding a 3 ft section of cheap stove pipe on the top and see whether now you can close the air fully and keep flames going (in the top of the firebox). If yes, replace that section with 3 ft of class A chimney pipe.
The attached link is what I am hoping to install. Once I have a good fire going I can have the damper about 20 - 25% open. I am only installing the reclaimer to get as much heat from my stove as possible.
I stand corrected Grisu. If I have a fire going and shut down the damper, I will get flames toward the top of the fire box (maybe going up the flue) that eventually die down. The insulated flue pipe is class A, not double wall. A local contractor installed it a few years ago.
https://www.google.com/search?q=Mag...at+Reclaimer&tbm=shop&spd=9930516199373497513
I stand corrected Grisu. If I have a fire going and shut down the damper, I will get flames toward the top of the fire box (maybe going up the flue) that eventually die down. The insulated flue pipe is class A, not double wall. A local contractor installed it a few years ago.
https://www.google.com/search?q=Mag...at+Reclaimer&tbm=shop&spd=9930516199373497513
Grisu
Minister of Fire
That is exactly what you should not install in your flue. A chimney fire is not fun and may easily burn your house down. That little gain in heat is not worth the risk. When run properly your stove should only lose a fraction of its total heat output up the flue.
With the super-dry bricks you should be able to close the air more. Try the trick with the added stovepipe section next winter and see if you can shut down the air completely while keeping the flames going in the top of the firebox. That will reduce the amount of heat you lose up the flue without creating an unsafe condition.
I also recommend to get a second thermometer for the stovetop to see if you run the stove hot enough.
With the super-dry bricks you should be able to close the air more. Try the trick with the added stovepipe section next winter and see if you can shut down the air completely while keeping the flames going in the top of the firebox. That will reduce the amount of heat you lose up the flue without creating an unsafe condition.
I also recommend to get a second thermometer for the stovetop to see if you run the stove hot enough.
At the very least I have settled a bet that my brother and I have been having. He is (still) insistent that a damper above the stove would be beneficial because it would trap the heat in the firebox, essentially putting more heat in my home. It did not make sense to me because there is already a damper under the stove.
It is easy enough to add another section of pipe to the flue. I will try this. What should my stovetop temp. be? Grisu, why are you against the installation of the reclaimer? Bad experience?
It is easy enough to add another section of pipe to the flue. I will try this. What should my stovetop temp. be? Grisu, why are you against the installation of the reclaimer? Bad experience?
We know the product pretty well. It will reduce draft which is not what is needed here. Has the insurance company approved?
You are correct. Your brother is most likely thinking about old school stoves that have no secondary combustion. Their typical loading method is burn then smolder. They are more inefficient than your stove and let more heat go up the flue so adding a key damper to the stove pipe was not uncommon.
You are correct. Your brother is most likely thinking about old school stoves that have no secondary combustion. Their typical loading method is burn then smolder. They are more inefficient than your stove and let more heat go up the flue so adding a key damper to the stove pipe was not uncommon.
Grisu
Minister of Fire
I never had one and will never have one. Do a forum search and you should get some firsthand experiences. Here is one thread why you should not use one: https://www.hearth.com/talk/threads/heat-reclaimers.81160/ Take especially note of the post (#13) of stoveguy2esw who works for a stove manufacturer.Here is another instructive post: https://www.hearth.com/talk/threads/heat-reclaimer.27105/
I don't know your particular stove model but assume it is simple steel stove. 500 F to 700 F on the hottest spot of the stovetop would be something I would shoot for during the peak of the burn.
Tell your brother that for a few minutes he may be right. But when you start restricting draft too much the stove does not pull in enough combustion air. Your fire dies down due to lack of oxygen and you will get less heat.
I don't know your particular stove model but assume it is simple steel stove. 500 F to 700 F on the hottest spot of the stovetop would be something I would shoot for during the peak of the burn.
Tell your brother that for a few minutes he may be right. But when you start restricting draft too much the stove does not pull in enough combustion air. Your fire dies down due to lack of oxygen and you will get less heat.
Last edited:
Like others have said do not put a heat reclaimer on there. They are horrible devices that have no place on a wood stove ever. We will no longer clean wood stove chimneys with them on.
Ok guys. I have not asked my insurance co. and do not think I will. What I have taken from your advice is that I will get another thermometer for the top of the stove and add another 3' section to the top of my flue to increase draft and overall temperature. Thank you very much for your help and God Bless.
Grisu
Minister of Fire
And when you add the section to the chimney, see if you can close the air more while sustaining a good burn. If that works you will get more heat out of your fuel.
Huntindog1
Minister of Fire
You might check your door gasket or for cracks in stove maybe too much air is getting into the stove this flushes your heat up the flue also a piper damper will give an extra way to control the air flow thru the stove. Also try to get your stove shut down a little sooner to its low burn setting do it in increments. Also use bigger splits that burn more slowly.
- Status
Similar threads
