Air/draft issue & downdraft/smoke from cleanout

[emorems0]

This is year 2 with our wood stove (Magnolia/U.S. Stove 2015?) and we've had pretty constant problems with the air. Our first season was a learning experience, I've never had a wood stove before and while my husband grew up with one, it was an old, inefficient beast that could burn anything. Lots of smoky starts, airing out the house, and just barely getting into the 'burn zone' on the chimney pipe temp gauge. We talked about going up one more section of chimney pipe to try and improve draft, but never got around to it (pipe is well above roof lines, but just at the recommended height for the stove). The house used to have an old wood stove piped through a thimble into a masonry chimney - we took out the cracked terracotta, re-lined, and extended it 4ft above the masonry chimney cap with a double wall chimney pipe. We also dropped a cleanout pipe (round to oval to get through the damper area) from the Tee for easier cleaning. Here's the set up:

SO, This season started okay... I realized that I never fashioned a cap of some sort for the bottom of the cleanout pipe - it's oval, so I couldn't just buy one. And I assumed that was the reason we were having such issues with the air last year. When we cleaned the chimney, the chimney itself was perfectly clean, but the stovepipe was PACKED with creosote. I don't have a good feel for how the air was moving last year without that cleanout cap, but it was clear that the creosote was forming only in the stovepipe and it would extend out into the Tee and then fall down. It was the dry flakey stuff and was pretty easy to clean.

To start this season, we disassembled the stovepipe to clean it, removed part of one brick on top to increase airflow to the fire box (as recommended on one of the Magnolia threads here), and I fashioned a make-shift clean out cap out of some aluminum foil because it was the best I could do as I was leaving for Thanksgiving. That night, the fire burned GREAT, we all celebrated that I fixed the stove... but when I was gone for thanksgiving, hubs was burning unseasoned wood (still stuck in the mindset of the old stove he grew up with and we just didn't get wood put up like we wanted). Now we have shiny creosote in the chimney and stovepipe and we've had water/condensation dripping from the clean out... the aluminum foil cap is short term at best, but when I tried to make one from aluminum flashing, I just couldn't get it sealed well and smoke has been coming out of the cleanout. THIS is what I am most concerned about, I don't recall having this problem last year when the cleanout didn't have a cap at all (and we definitely burned some wet wood last year), I don't understand how the smoke is dropping 3ft below the Tee to leak out of my make-shift clean out cap (and that is a serious safety concern - carbon monoxide, right?).
*behind the wood stove, silver is the make shift cleanout cap leaking smoke into the original fireplace.

Symptoms: fire seems like it is starved for air whenever the door is closed, can't get a 'roaring' fire going - it just turns to red coals and burns low and slow (which does heat the house just fine, but it isn't getting hot enough to burn cleanly), smoke is dropping down from the Tee and leaking from the clean out (dangerous?), water/condensation dripping down the chimney pipe to the cleanout.

Things I've tried: thorough cleaning, removing brick on top for airflow, and make shift cleanout cap (a couple of great burns immediately after, but now we have shiny creosote 1 week later and I can't get it clean). Later: Removed the chimney cap and spark arrestor (they were pretty dirty, I was expecting a big improvement in draft, but really didn't see any), burned one of those creosote cleaning packets, stuck an extra 2ft piece of rigid liner in the top of the chimney for an extra 2ft chimney height (single wall/uninsulated, but better than nothing? Didn't notice any difference), split some 60 year old cherry lumber that's been stored in my barn/garage to see if I could keep that burning with the door closed (nope, it lit right away, but snuffed out as soon as I closed the door, even waiting until it was fully engulfed), and finally, to try and check if it was lack of airflow into the fire box (since it snuffs out as soon as the door is closed), I pointed a hair dryer into the air inlet to see if the fire would perk up... it didn't, but it did blow some smoke through the door gasket - a pretty clear sign there isn't a clog in the air intake.

So, now what? What else can I do? Our mini split isn't really working right now and temps are going to drop again in the next few days. We need to be able to burn a fire, but we can't do it safely if there is smoke coming down through the cleanout. The cleanout pipe is a Duravent, round to oval flex pipe (6" round), any better solutions for a cap for the oval part? I'm planning to run the chimney brush through the chimney once it is cooled down enough tomorrow (it was too hot today), but I don't know that it will do much for the hard, shiny coating of creosote (it's thin, but even a thin coating can make a difference in draft, right?). What else? This seems like a bigger problem than a thin coating of creosote. Chimney pipe is from Rockford, so it isn't easily compatible with the Duravent or Selkirk that I can easily get locally or on Marketplace (if the solution is a taller chimney).

 

[EatenByLimestone]

How tall is your chimney? Do you have a cap on it? Did you sweep after the creosote converter? Are you still burning wet wood?

 

[emorems0]

Chimney is 12' from the top of the stove (which is the minimum that the stove requires). At this moment, it has an additional, uninsulated extension of 2ft and no cap. Heights and proportions in my set up diagram are accurate. The masonry chimney is really big/wide and solid, the rigid liner inside it does have a ceramic blanket insulation. The 4ft class A is double walled, and temporary 2ft extension is single wall (that's not shown on the diagram). Could the difference in insulation of the chimney be contributing to down draft?

My intention was to sweep after work yesterday (one day after using the creosote converter), but the stove and chimney were still too hot from the previous burn. I will do it tonight after work.

We purchased a load of seasoned wood last weekend, but it got rained on before we could get it restacked on the porch. We bring it in to dry by the stove before we burn it. I'm also planning on buying a moisture meter when we get paid tomorrow so that we can check everything before we burn it. I think it will be eye opening for my husband just how dry the wood needs to be for these EPA stoves.

 

[moresnow]

Chimney is 12' from the top of the stove (which is the minimum that the stove requires)

You essentially have two 90 degree turns in your venting path. Rule of thumb seems to be that you lose two feet of effective chimney length for each 90. You could be well short of the stove's required effective chimney length because of the two 90's.

Post a pic of the entire stove install. A pic from in front of the stove and one from the side showing your stove pipe entering the thimble.

Guessing your purchased "seasoned wood" is wet. Unlikely that purchased wood is actually dry.

Post when you get your new moisture meter home.
You will need to select a handful of splits from your supply.
Bring those splits indoors overnight to bring them to room temp.
Take those room temp splits back outdoors and re split them.
Immediately test the freshly exposed inner face of each split near the center for an accurate reading.
Testing any other exterior location on a split means nothing. Just a heads up!
Let us know what you find.

You are on the correct path capping the cleanout. Must be done.

 

[stoveliker]

All of the above, but given that the set up burned well initially (you were celebrating), I think the change for the worse is because you have an obstruction in the chimney .

I.e. not only a shiny thin layer but a big glob someplace.

 

[EbS-P]

The bottom clean out wasn’t sealed. This must be addressed. Start by really sealing the clean out well. Test.. Then temporarily add a section of whatever pipe you can find to the top and see if it improves.

 

[emorems0]

All of the above, but given that the set up burned well initially (you were celebrating), I think the change for the worse is because you have an obstruction in the chimney .

I.e. not only a shiny thin layer but a big glob someplace.

This was my initial thought... that there was a clog of some kind. I intended to push the chimney brush through it after work last night, but it was still too hot from wood/coals my husband put in sometime in the morning. I told him no fires today so that I can push the brush through tonight.

The bottom clean out wasn’t sealed. This must be addressed. Start by really sealing the clean out well. Test.. Then temporarily add a section of whatever pipe you can find to the top and see if it improves.

Any tips on how to seal the cleanout? Everything I've tried so far still lets smoke out and when I looked last year to purchase an oval cap, I couldn't find any. It's also pretty hard to get under there with more than a single arm, it's tight quarters without moving the stove.

I did add a temporary 2ft pipe to the top of the chimney last night, expecting an improvement in draft, but not seeing any difference.

 

[emorems0]

You essentially have two 90 degree turns in your venting path. Rule of thumb seems to be that you lose two feet of effective chimney length for each 90. You could be well short of the stove's required effective chimney length because of the two 90's.

Post a pic of the entire stove install. A pic from in front of the stove and one from the side showing your stove pipe entering the thimble.

Guessing your purchased "seasoned wood" is wet. Unlikely that purchased wood is actually dry.

Post when you get your new moisture meter home.
You will need to select a handful of splits from your supply.
Bring those splits indoors overnight to bring them to room temp.
Take those room temp splits back outdoors and re split them.
Immediately test the freshly exposed inner face of each split near the center for an accurate reading.
Testing any other exterior location on a split means nothing. Just a heads up!
Let us know what you find.

You are on the correct path capping the cleanout. Must be done.

Outside with the temporary 2ft extension (single wall) stuck in the top of my class A double wall chimney pipe. Masonry chimney is solid brick and mortar, it's not hollow, I was barely able to get my 6" insulated liner down after breaking out the clay tiles. Not sure if that matters in terms of mass or insulation differences between that section and the class A.

Inside picture (best I can find on my phone while I'm at work)... our first burn after getting it all set up last year

I'll take better pictures when I get home tonight.

 

[emorems0]

You essentially have two 90 degree turns in your venting path. Rule of thumb seems to be that you lose two feet of effective chimney length for each 90. You could be well short of the stove's required effective chimney length because of the two 90's.

Chimney length or chimney height? The current 12ft (plus temporary 2ft) is only the vertical distances, I have a 22" snout into the masonry... if that counts toward chimney length, that's an extra 2ft (I didn't think horizontal lengths of chimney should be counted).

 

[stoveliker]

Some mfgs recommend to add 2 ft height to the minimum recommended for each elbow and each foot of horizontal run.
That would mean 8 ft extra in your case. I don't think that's needed here, but you're likely short indeed.

 

[EbS-P]

This was my initial thought... that there was a clog of some kind. I intended to push the chimney brush through it after work last night, but it was still too hot from wood/coals my husband put in sometime in the morning. I told him no fires today so that I can push the brush through tonight.


Any tips on how to seal the cleanout? Everything I've tried so far still lets smoke out and when I looked last year to purchase an oval cap, I couldn't find any. It's also pretty hard to get under there with more than a single arm, it's tight quarters without moving the stove.

I did add a temporary 2ft pipe to the top of the chimney last night, expecting an improvement in draft, but not seeing any difference.

I’d probably see if I could ditch the round to oval and see if I could install a round clean out on the T. It doesn’t have to removable for cleaning I’d just vacuum out through the thimble. You don’t need the damper or frame. Don’t could be removed.

 

[Millar]

To fab a cleanup cap make another tinfoil one . Use this as a pattern to make one out of ideally the same metal as the pipe . If you can't find flat stock get snap together pipe and flatten it out . Set your pattern on it and trace around the oval , mark another bigger oval 3/4 to one inch from pattern oval . Cut outside line with tin snips , then roughly every 3/4 of an inch cut from outside in to original pattern line . Bend these cut strips to create a collar . Wear gloves so you don't get blood everywhere . Some of the notching may need to be cut in a slight v to get the desired bend . Use a scrap piece to practise on as your first attempt the tighter bend may need notching closer together and you may be able to have it farther apart in other spots . Notching will possibly need to extend past your pattern line depending on how square you can bend the metal , pliers should work for that. Screw it in place with self tapping screws or sheet metal screws .

If someone close does ductwork take them your pattern to fab a cap if these instructions sound idiotic.

I can't get your pictures to show up so am only going by your notes to give my 2 cents worth .

 

[EbS-P]

To fab a cleanup cap make another tinfoil one . Use this as a pattern to make one out of ideally the same metal as the pipe . If you can't find flat stock get snap together pipe and flatten it out . Set your pattern on it and trace around the oval , mark another bigger oval 3/4 to one inch from pattern oval . Cut outside line with tin snips , then roughly every 3/4 of an inch cut from outside in to original pattern line . Bend these cut strips to create a collar . Wear gloves so you don't get blood everywhere . Some of the notching may need to be cut in a slight v to get the desired bend . Use a scrap piece to practise on as your first attempt the tighter bend may need notching closer together and you may be able to have it farther apart in other spots . Notching will possibly need to extend past your pattern line depending on how square you can bend the metal , pliers should work for that. Screw it in place with self tapping screws or sheet metal screws .

If someone close does ductwork take them your pattern to fab a cap if these instructions sound idiotic.

I can't get your pictures to show up so am only going by your notes to give my 2 cents worth .

This is good. Seal it all up with high temp RTV. do it such a way that you can cut around the rtv to remove the cap. I would not use galvanized. Zinc poisoning is a real danger.

 

[moresnow]

Worth checking your stove pipe sections for restriction as mentioned. Wet fuel can cause problems quickly.
Looking forward to seeing the moisture content results. Sounds like a wet fuel issue your fighting.
Confirm none of the horizontal pipe section is running downhill (connection still good?) also. Rather crucial!

 

[emorems0]

Some mfgs recommend to add 2 ft height to the minimum recommended for each elbow and each foot of horizontal run.
That would mean 8 ft extra in your case. I don't think that's needed here, but you're likely short indeed.

Well, I'm certainly kicking myself for not making the time/budget to add an extra 4ft this summer like we planned... I wish I had gone with a more readily available brand so I could just pick up another section on marketplace for $100 on a 1 day turnaround. I don't have an extra $400 right now to wait on an order from Rockford, and I can't figure out which (if any) locally available brands are compatible.

I’d probably see if I could ditch the round to oval and see if I could install a round clean out on the T. It doesn’t have to removable for cleaning I’d just vacuum out through the thimble. You don’t need the damper or frame. Don’t could be removed.

I can't access the bottom of the Tee now that it is installed. I did put in a request for a custom cap from Rockford (that's where all of my other supplies are from), and this is what they said about expected fit "We should be able to fabricate an oval end cap for you. It is not going to be a perfect fit however, it will be close to where you can use some stove gasket to seal it."

This is good. Seal it all up with high temp RTV. do it such a way that you can cut around the rtv to remove the cap. I would not use galvanized. Zinc poisoning is a real danger.

RTV? Miller's description of cap fabrication is very similar to what I tried to mock up after my first aluminum foil cap came off - I have a stack of aluminum flashing pieces from a previous project, but the weren't quite big enough so I layered 2 pieces perpendicular. I attached it with hose clamps. There are a lot of gaps though, I think it would help to pop rivet the two layers together, but I need to seal up the flaps that fold up the sides because smoke was able to pour through those seams. I have some stove and gasket cement, but that needs to get hot to cure, so I didn't think it would work well here.

Worth checking your stove pipe sections for restriction as mentioned. Wet fuel can cause problems quickly.
Looking forward to seeing the moisture content results. Sounds like a wet fuel issue your fighting.
Confirm none of the horizontal pipe section is running downhill (connection still good?) also. Rather crucial!

When I clean tonight, I will recheck the slope of the horizontal bit. The Tee can't really move vertically because it is attached to rigid liner and secured at the top plate, but there is a little room for adjusting on the stovepipe side. I did not check the slope after I took it apart to clean it, so I will do that tonight.

 

[EbS-P]

RTV?

High temp silicone sealant.

 

[stoveliker]

I would use a (door) gasket or thinner gasket instead.
That does not stick (makes it easier to disassemble if needed), and should seal sufficiently. (Stove pipe seams are never perfectly sealed, so there is no need for a perfect airtight seal here either. Good, gaseketed, seal should suffice.)

 

[emorems0]

I would use a (door) gasket or thinner gasket instead.
That does not stick (makes it easier to disassemble if needed), and should seal sufficiently. (Stove pipe seams are never perfectly sealed, so there is no need for a perfect airtight seal here either. Good, gaseketed, seal should suffice.)

That works, I do have extra door gasket... getting ready to disassemble and re-clean now.



*most of the soot on the brick is from the previous owner/hookup, although we did contribute a little after I first cleaned the stovepipe... apparently, a couple of screws didn't thread properly and pushed the inner pipe joint instead of screwing into the hole. It has since been fixed and we aren't getting smoke through those joints anymore.

 

[emorems0]

Success! There was a big clog of creosote about halfway up the main chimney. I did the best I could on the pipes with just chimney sweep, there is still a layer of shiny creosote, but we are going to keep using the creosote converter and sweep more often.

I also spruced up my makeshift cleanout cap. I riveted the two layers together and folded the tabs down to help hold the pipe clamp. I also used some extra stove gasket around the bottom of the pipe to help seal it up.

Black marks are tape residue from a futile attempt to seal leaks on the first try.

I preheated the stove/pipe with a space heater for extra assurance because it was completely cold. I can't post the video of lighting it bc the file is too large, but it lit right up, smoke rolled around inside the box but didn't come out even with the door wide open. This was 4 minutes after lighting. Temp gauge already right in the middle of the green.

It actually got up into the red a little before I realized I should close the air. I did put a lot of smaller splits in there because I was just starting it up from cold, buy I've never had it burn that fast and hot before, usually we have to watch it closely and close the air in the smallest increments. And of course, now I'm worried about the shiny layer of creosote that I couldn't completely remove from the pipes.

 

[begreen]

Progress! It should run a lot better now.
The thermometer looks like a stove top model, based on the ranges. It appears to be reading at half-way between 300 and 600º or 450º. The temp inside of the flue is about twice that or 900º which is too hot. It should be more like 250- 300º when the air is closed down.

 

[EatenByLimestone]

I see a potential issue with a permanent type cap on the bottom of the oval clean out. If you have water dripping down into it, there has to be a way to remove the cap. Otherwise, you’re going to end up with a block of flammable tar down there.

 

[stoveliker]

Pipe clamp is not permanent?

 

[Millar]

Used a different browser and was able to see your pictures , temporary clean out cap looks exactly like something I would make with whatever is on hand . I have lurked on this site for years and the knowledge and eagerness to help solve issues is astounding .

 

[emorems0]

I see a potential issue with a permanent type cap on the bottom of the oval clean out. If you have water dripping down into it, there has to be a way to remove the cap. Otherwise, you’re going to end up with a block of flammable tar down there.

Pipe clamp is not permanent?

Correct, the cap is removable by releasing the pipe clamp. I actually don't remember having issues with water dripping last year, so I'm guessing that will be mostly resolved now. The clog in the chimney pipe was wet, I think it was catching and holding/condensing the moisture rather than letting the steam escape the top of the chimney as it normally would.

 

[EbS-P]

Correct, the cap is removable by releasing the pipe clamp. I actually don't remember having issues with water dripping last year, so I'm guessing that will be mostly resolved now. The clog in the chimney pipe was wet, I think it was catching and holding/condensing the moisture rather than letting the steam escape the top of the chimney as it normally would.

You were always drafting moist room air up a cold chimney when the stove was out. Then when it was burning the flue gasses were be cooled by the house air below condensation temp.