Manual Damper in Double Walled Stove Pipe?

warminmn wrote:Yep, I agree about it being fine to use the MPD on your double wall.

No installer has used the stove you have in your house, with your chimney and coal, so they do not know how to use your stove in your house. try a few different things and figure out what works for you. Your results may differ a lot from mine and thats fine.

I ended out cracking my grate in I think the 4th? year I used it. Its the shallow ash pan. It should probably be dumped twice a day to keep air space underneath the grate. I was careful but still cracked mine. That side door is wonderful. Many stoves could benefit from having one.

If you search this site for this stove, you will find a lot of great advice. my posts were a learning experience as it was my 1st coal stove, so probably trust my later posts more But several posts from other owners too.

If you have your stove where you can enjoy the fire view, I used to like pulling the hopper and burning stove sized coal in it, banking it towards the back and piling it high. Very pretty, kind of looks like charcoal burning.

Its a pretty decent stove, but needed a deeper ash pan. Its much better looking than most modern stoves are. Im too far away from coal country to find a used stove but given the chance I'd get another grate if it was cheap, but not at the prices Ive seen.

Thanks very much for the great advice! Much appreciated!

Sunny Boy wrote:Not suggesting that you change it all, but I think part of the problem is using double walled pipe indoors. It retains more heat in the flue gases causing a stronger draft.

As far as I know, rarely is double walled pipe need indoors except when the pipe is close to combustible surfaces, or the chimney system does not provide a strong enough draft, or to keep wood stove exhaust hot enough to reduce creosote buildup. Sounds like maybe your coal stove installers are really wood stove installers that don't know much about setting up and operating coal stoves. This happens alot.

Single walled pipe would shed more heat within the house thus lowering the draft pressure within the pipe. Then your bi-metal thermostat might do a better job of controlling the burn rate ?

Paul

Great insights, Paul. Thank you. I hadn't put 2+2 together regarding the double walled keeping the flu gases hotter, thereby increasing the draft. Makes perfect sense. I specified the double walled pipe to the installer for the exact reasons you mentioned; I needed to reduce distances to the combustible (wood) wall. I also have a heat shield with 1" stand-offs from the wall so I could do the same with the stove itself, and reduce the standard 24" clearance from the stove back to the combustible wall. I also went to town studying the very best and safest approach to the hearth pad build up. In this order from bottom up: 3/4 plywood, Micore 300 (boy is Micore 300 hard to find...), 1/2 Durock cement board, 1/4 thinset, 1/4 stone tile. I did side/front/back clearances to not only meet the requirements of my stove, but likely replacement models as well. I didn't want to have to rip it out and start over if I replaced my stove! You can see I'm really big on safety which is why I really value the experience and opinions of people on this board.

Thanks!
Rob

Is this it?

Stove and Stove Pipe NFPA Clearances.

Sunny Boy wrote:Rob,

Yes, a heat shield on the pipe - only on the side of the pipe where the wood wall is- will allow the pipe to be at the same reduced distance that a double walled pipe would. But having open sides to allow convection currents, the shield would not trap anywhere near as much heat inside the pipe. So you get to keep more of the heat you paid for rather than help warm the neighborhood.

It's simple to make a heat shield from light gauge hardware store sheet metal, paint it with rattle-can BBQ paint, and mount it to the pipe using the same 1 inch standoffs as the wall shield.

Richard had a sticky for a thread about stove clearances in the old forum, but I can't find it now. Maybe Richard, or one of the mods, knows where the thread is ?

In the meantime, here's two pages - bottom one is a PDF file needing to be clicked on- from the National Fire Code about clearances for stoves and pipes and how to reduce those clearances.

Paul

Thank you Paul. I've attached a picture which might help explain as to why I went double walled as opposed to a heat shield for the whole distance of the pipe. I would have had to go to the ceiling, which would have been a bit much. Also, aesthetics were really important as this is a pretty nice log cabin.

Sunny Boy wrote:Yup ! That's it CS - thanks.

Can it be made into a sticky again, where stove newbies can find it ?

Paul

Looks like Fearless Leader did away with the stickies and put them at the top of the sub forum in an announcment thread. See it here.

Chimneys, Coal Bins, CO Detectors and Thermostats

We should probably ban all the newbies that fail to heed his instructions!

Very nice setup Ossa. Mine has a fancy cast iron top and did not have the ash catcher in the front that yours has. I see why you used double wall in that situation.

I did remember something else I did and that was a really thick piece of steel in the front to raise the bed an inch or 2. I remember there kind of being slots it fit into. You dont want it touching the glass. It was mostly useful for operating without the hopper or for burning wood. There was an option with these stoves for a slip in log stopper. They are really expensive to buy.

I have bought 8" single wall pipe and cut it lengthwise in half for heat shields on 6" pipe. (This shield info is mainly for others, not the OP)

warminmn wrote:Very nice setup Ossa. Mine has a fancy cast iron top and did not have the ash catcher in the front that yours has. I see why you used double wall in that situation.

I did remember something else I did and that was a really thick piece of steel in the front to raise the bed an inch or 2. I remember there kind of being slots it fit into. You dont want it touching the glass. It was mostly useful for operating without the hopper or for burning wood. There was an option with these stoves for a slip in log stopper. They are really expensive to buy.

I have bought 8" single wall pipe and cut it lengthwise in half for heat shields on 6" pipe. (This shield info is mainly for others, not the OP)

Thanks for the feedback and ideas!

You folks were so helpful in sharing your experience and advice. I thought I'd follow up with my experience which might be helpful to some...

Well, with heating season upon us, I embarked on my damper journey, based on the above advice and other research, I decided to start with actual draft measurements. I purchased a digital manometer - a $50. mistake. I was hoping to be able to have a device that would be helpful in the shop as well as with the stove. No where near the accuracy I needed. I moved to the popular choice and installed a Dwyer unit. I also installed an MPD as my draft was way too high. The MPD is like others decribed here with several holes. Even with the MPD fully closed, with no wind, I'd pull a draft of .07-.10 and have to have my thermostatic damper on the back of the stove opened just to a sliver to avoid over-firing. The thermostatic damper is a big round disk that covers a round hole on this stove - it's on a long arm. When just cracked as it had to be, I big gust of wind could pull it shut and smother the fire. Not good with 40 lb of coal in the hopper. What a mess. With this setup, a slight wind would increase the draft to .12 and a truly windy day would increase the draft to .30; all this with the MPD closed. Opening the MPD would increase the draft by maybe 25-50%.

While the MPD was helpful, it was not managing my over-draft condition. As discussed, for clearance reasons, I have double-walled stove pipe. This complicates the installation of a barometric damper. I use ICC Ultra-black pipe, which is not compatible with other brands, so I got a ICC UB tee and a Field Controls RC baro (which has a 6" male connector). ICC sells a female-to-female adapter, but that is on back order; should arrive in two weeks. In the meantime, I was able to do a kludge and install the baro. Even though the baro is 6" male and the inside wall of the tee is also 6" male, I was able to slip the baro over the inner wall of the tee and anchor with a screw while awaiting the adapter - which will also make the installation more asthetically pleasing by connecting to the tee via the outer and inner walls as designed.

I was afraid with my jet-engine draft, the baro would not have enough flow to get me where I needed to be - .05-.06" H2O. I was thinking I may need to install the MPD upstream of the baro, but I decided to first try the baro alone as installing the MPD was going to have to be on the neck of the tee itself which would not have been ideal.

I found it took longer to get a nice bed of wood embers to ignite the coal. Not surprising with a more temperate draft with the baro. I was patient and let more wood burn longer to be sure. I didn't want a fail on my first fire with my new baro!

Here's a pic of the install, not bad, but it will look better once the adapter comes: You can see the baro is quite opened up, working hard to keep the draft where it needs to be. It turns out I still have some adjustment room on the control knob and the baro holds the draft nicely, even with some strong winds. No need to also install the MPD! Glad I waited...

Here's the proof of the baro doing a great job: Turns out the wind kicked up once the fire got going and the baro is doing a dance, but holding the draft at exactly .05 as advertised. I'm a convert already!

As so many have said, great peace of mind.

So there you have it. I'm done with this adventure! Thanks for all the help.

Rob

The baro is magic

If the draft is closing your air intake door tight, you can put a paper clip over the round part so it cant close completely. Or drill a very small hole in the round part. Might not matter now that you have the draft down to where you want it.

Congrats on getting her up and running!

warminmn wrote: ↑

Sat. Dec. 16, 2017 4:34 pm

If the draft is closing your air intake door tight, you can put a paper clip over the round part so it cant close completely. Or drill a very small hole in the round part. Might not matter now that you have the draft down to where you want it.

Congrats on getting her up and running!

That's a great idea with the paper clip. I should have thought of that before! I don't believe I'll need it now with the baro humming along. Thanks!