Single wall pipe gaps

[Rancher22]

I'm "convinced" smoke was leaking out my old pipe.

Smoke was leaking out somewhere ...of that there was no dispute. Door closed, new gasket, and the house always got smellier with the air monitor showing climbing dust ...so let's go with the pipe. It had been drilled so many times over, and there were different manufacturers of the straight pieces and the elbows, plus I didn't/don't know what else to try. Who knows.

Regardless, I bought all new fresh pieces, but putting it together - there's gaps.

The above is the same photo, with and without flash. (Yes there's a bag blocking the downdraft)

This photo shows the gap at the collar (?)


The gaps are all the seams of the pipe - not allowing it to be fully round.

Are there tips/tricks to avoid these? Seal these?

Thanks in advance for any help (my patience in getting this stove to cooperative and be functional is waning)

 

[Kevin Weis]

Would need to see more pics of the outside of the pipe from stove to ceiling. Not sure it's installed correctly otherwise.

 

[Rancher22]

Above is how I inherited the stove. Stuck out nearly 12 feet from the wall in the middle of the basement with a 9' near perfectly level horizontal section in the middle.
Allegedly used for years without issue to heat the house.
Knowing nothing, I used it last year and believe it or not, had a hard time getting a good draw and often filled the basement with good blasts of smoke.

Above shows what I tried this year. I removed two 3' sections, leaving me with one 3' piece, that is on a "better" angle than previous.
I still had trouble with draw and this forum encouraged me to do better. When I shut the fire down, I could really feel a backdraft (? Downdraft? Stack effect?) with smelly air blowing out the joints, especially at the elbows.

The pipes had been drilled a dozen times with many holes in each male section, and I bought all new (single wall) pipe for a nice fresh start. Again, the stove pipe overall length has been reduced with an even further improved angle on the "long" section (now only 2')
It's not fully assembled in the above picture as you can tell, I was just test fitting everything - but the large gaps in the joints at the seams are discouraging.

Above are exterior photos of it assembled were the biggest two offenders that I can see are.
I certainly understand that IN THEORY the draw will be pulling air into the chimney vs pushing it out - but, that's not my experience in the first 45 mins each morning. Plus if we go away for a few days, I don't want large pathways for stinky air cold chimney air to blow into the basement when it's cold.

If there's a trick to getting this pipe to be actually round and fit nicer together, I'd be so grateful. Otherwise, I'm getting closer and closer to writing the propane company a blank cheque to heat this place this winter.

 

[Kevin Weis]

That huge horizontal run is killing your draft. Can you shorten that up by half? Yeah there's some gaps there at the seams. They tend to flatten out like that when you fasten the seam together. Fix for that is to make it round after connecting the seam halves together or stove cement in the gaps. Better yet use the seamless style pipe or double wall. Just my thoughts on it.

 

[Rancher22]

It was 9' of horizontal run and now it's 2' of a somewhat horizontal/angled run.
I can't shorten it any further or it will be too close to the furnace.

How do I "make it round" after connecting the seams? With pliers and just bending?
As for stove cement, how would I undo that for cleaning?

I appreciate the thoughts regardless.

 

[kborndale]

That huge horizontal run is killing your draft. Can you shorten that up by half? Yeah there's some gaps there at the seams. They tend to flatten out like that when you fasten the seam together. Fix for that is to make it round after connecting the seam halves together or stove cement in the gaps. Better yet use the seamless style pipe or double wall. Just my thoughts on it.

You must have missed his post right before yours where he explained how he did shorten the horizontal run by more than half.

 

[BillBurns]

Thats a lot of level pipe. I cant believe it works well, but it must I guess.

 

[Rancher22]

Thats a lot of level pipe. I cant believe it works well, but it must I guess.

It didn't. Hence my leaky "fix".
YouTube said to roll the pipes around on the ground for a bit until they are round again. I tried that and there is some improvement, but I am still curious about the pros and cons of this stove/gasket cement.

 

[kennyp2339]

Rounding the pipes will not fix the problem, when the stove is hot the chimney will run in vacuum, somewhere between the warm and cold the equilibrium of vacuum to static to down draft occurs due to stack effect.
Do a little research on stack effect, because if you fix the chimney, eventually the smoke will just come out the air inlet of the stove still keeping the smoke smell and potentially co, please have a co detector in the basement

 

[Kevin Weis]

It was 9' of horizontal run and now it's 2' of a somewhat horizontal/angled run.
I can't shorten it any further or it will be too close to the furnace.

How do I "make it round" after connecting the seams? With pliers and just bending?
As for stove cement, how would I undo that for cleaning?

I appreciate the thoughts regardless.

On mine I've done it by hand but you will not get it perfectly round at the seam. The furnace/stove cement will pop out when you take it apart for cleaning or replacement. Alternative as mentioned is to use factory sealed seam stove pipe. It is better quality but at double the price. Just looking at the pics again it looks like you may have two appliances in one flue, no? Furnace and woodstove in one flue? That would be a code issue I think no matter where your located and may be a cause of the draft issue. Other folks here can better advise on that than me.

 

[Rancher22]

On mine I've done it by hand but you will not get it perfectly round at the seam. The furnace/stove cement will pop out when you take it apart for cleaning or replacement. Alternative as mentioned is to use factory sealed seam stove pipe. It is better quality but at double the price. Just looking at the pics again it looks like you may have two appliances in one flue, no? Furnace and woodstove in one flue? That would be a code issue I think no matter where your located and may be a cause of the draft issue. Other folks here can better advise on that than me.

The hot water chimney and wood stove share an exterior masonry chase, but do not share a flue.

I've seen double wall pipe for 4-5x the price. Is there factory sealed seam single wall?

 

[Rancher22]

Rounding the pipes will not fix the problem, when the stove is hot the chimney will run in vacuum, somewhere between the warm and cold the equilibrium of vacuum to static to down draft occurs due to stack effect.
Do a little research on stack effect, because if you fix the chimney, eventually the smoke will just come out the air inlet of the stove still keeping the smoke smell and potentially co, please have a co detector in the basement

I hear thee, but I don't know how to fix this "stack effect"
My chimney is probably 25-30' tall from the tee, in an exterior masonry chase. The cap is over 6' above the roof line at the eaves, and follows the rule of being 2' taller than any roof line within 10'
What am I missing?
(other than steps out my back door)

 

[EatenByLimestone]

You can push furnace cement into the cracks. As the pipe moves with hot/cold, it will come loose, but will sit in the crack and do it’s job.

 

[Kevin Weis]

Just throwing some things out here. What separates the two flues? Is there a masonry wall between the two, just insulation or just air between the two liners? Regardless though I'm wondering if they still aren't "playing "with each other just being that close together. There's plenty of height there so no issue with that. Other than that maybe some slight negative pressure the area of the stove until the flue can heat up.

 

[Rancher22]

Just throwing some things out here. What separates the two flues? Is there a masonry wall between the two, just insulation or just air between the two liners? Regardless though I'm wondering if they still aren't "playing "with each other just being that close together. There's plenty of height there so no issue with that. Other than that maybe some slight negative pressure the area of the stove until the flue can heat up.

I couldn't tell you what's inside that chase to be honest. I suppose I could climb up there and pry that cap off and take a peek. What's the physics that chimney 1 would be affecting chimney two in the above scenarios?

The actual peak of the roof is probably even with the chimney cap(s)
It's more like 15+ feet away - but do you think adding another 2' section of stainless chimney could still help?

I did have an energy audit and the weak spot was my basement walls, but the windows and attic all were good, so I'm not sure what's contributing to this "stack effect"

 

[begreen]

I'm not sure what's contributing to this "stack effect"

Air leakage on the 1st and second floors, anything exhausting air (bath, kitchen, dryer fans), competing appliances like a gas/oil furnace or boiler. Radon fan?

 

[Rancher22]

After completely re-doing the stove pipe as per the advice on this forum, I'm still having the same problem.
(I also had my attic topped up to R-60 and the energy audit found no significant leaks that would contribute to the stack effect since my last post)

After a lengthy hiatus, I came down this morning with high hopes to have a successful fire.
I heated the pipe up very slowly for about 44 mins just a hair dryer and then eventually several of the (relatively) smokeless firestarter cubes. Added kindling and things were going well at the 1 hour mark. My magnetic thermometer was getting to about 300 degrees F when the bigger pieces started to catch.
No problems at this point - my air monitor shows no smoke/dust.

Then within a few minutes as the fire continues and temps hit about 400, my air monitor goes from green to orange to red.
I can see with a flashlight that smoke is coming out of every seam in the pipe, including the 45 elbow.

It's like no matter how long I coddle and warm up this (brand new) chimney, as soon as it gets to "Optimal Temps" it just can't handle it and dumps smoke out wherever it can.

 

[moresnow]

Hate to hear you are still struggling. Post a pic or two and explain how you changed your setup. Unless I have misunderstood your posts and missed it?

Still thinking about that first big step out your back door! Yikes....

 

[kennyp2339]

Is it the paint curing on the new pipe?

 

[EatenByLimestone]

Was it windy?

 

[bigealta]

I Second "was it windy"

 

[Rancher22]

"Is it the paint curing on the new pipe?"
...maybe? That wasn't the smoke I was seeing, but - maybe. What would that affect?

"Was it windy?"
Short answer, not really. Not today. But, for my knowledge - what does that affect?

Again, I took over an hour to warm this pipe/chimney up and there were no issues as I was creeping past 300 to 400 degrees F.
Seems like once I got to 400 however, it was just too much heat/pressure and the smoke came out wherever it could.
After doing an incredible job of stinking up the house again, the smoke seemed to stop. I've been running it now for a few hours without issue. I'm worried about getting this thing going in the morning again of course.
The stove had not been run for a couple weeks until I could get it inspected, and my loose understanding is that there could have still been some cold air near the top of the chimney causing some sort of block but ...after an hour? Is that possible?

Post a pic or two and explain how you changed your setup. Unless I have misunderstood your posts and missed it?

In my 2nd post (3rd of this thread) there are 3 photos showing the gradual shortening of the pipe. It also became less horizontal as a result. Perhaps hard to tell from the photos but that middle section goes from 9' to 3' to 2'

 

[kborndale]

Sounds like paint curing to me, was that the first time the new pipe hit 400?

 

[Kevin Weis]

I second/third/forth the paint curing. And eventime you hit a higher temp than before it will smoke again until it's finally cured at the highest temp.

 

[nola mike]

Just out of curiosity, have you swept your chimney?