Chimney Sweep's Advice

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ValentineHill

New Member
Sep 8, 2011
76
Seacoast, New Hampshire
After waiting 5 weeks, I finally got my appointment with a chimney sweep today. Hooray, I thought: no more worrying about whatever creosote my be lurking up in the upper recesses of my chimney.

However, the sweep said that I really should reline my chimney with a stainless steel liner. And that wasn't all. Since the 6" collar coming out of the back of my Jotul F400 goes through a 5" thimble into the chimney, he said that I needed (not should, but needed) to expand the thimble to 6". And -- here's the kicker -- the new 6" pipe wouldn't fit in the existing clay lined flue, so the existing flue tiles would have to all be removed before the stainless steel liner could be put in.

The proposed cost? "Three thousand, maybe three and a half thousand."

Obviously I'm not going to do it. But one thing about it did worry me a little -- reducing the pipe from 6" to 5" for the thimble. So I'm asking the group wisdom -- is reducing the pipe size through the thimble an issue or a risk?
 
Reduction in thimble changes draft because of volume change. 6 inch is 28.26 square inches, 5 inch is 19.625 square inches so suare inches is reduced by 8.63 inches which is 30.55 percent less. That is a pretty big difference, now as to will it matter, is it dangerous, etc. If the pro said it........

Also you can put in a new liner yourself, you can even knock out the tiles yourself. Not an easy job but doable, and will save some $$$.

Shawn
 
Thanks Shawn,

Well done on the math -- there's no denying that that's a significant drop in volume for the draft. However, do you think it makes a difference that the 5" is only for the thimble? It's 5" wide for 2-3" inches, and then it opens out into the 12"x8" flue. Does it matter that it's size is reduced for only such a short length?

Also, that 12"x8" is my own measurement from climbing the house today. The guy that the "professional" sweep put me in touch with had no idea what the measurements of my flue was, so, if I do reline it (which I'm definitely still considering) I at least won't have to take out the clay tiles.

Thanks!!
 
It's the same as trying to drink through a straw while pinching the bottom. Sure it's just the bottom, but things can only flow as fast as they can get through that restriction.

You should enlarge it to six inches.
 
Right, I'll put in a few calls and get it expanded. Thanks for the advice!
 
I am unfamiliar with that specific stove, with that said take this with a grain of salt but I think those who are familiar will chime in and support me with this.

You should most def. get that liner. The flue size is huge for that stove. The math is a 6 inch round liner (assuming this is the correct size for the stove) is only 28.26 square inches a 8 by 12 flue is 96 square inches. Todays stoves are designed with specific size flue in mind for instalation. You are TRIPLE the size which will slow the draft, and have a huge effect on the stove, you also have a gigantic flue to heat up to get those gasses going, let alone the creosote you will be making as those gasses cool on the humungous flue.

You really should get that sucker lined, you will most likely find your stove works better with the proper thimble and the flue lined.

Keep us informed on what you do and how things go.

Shawn
 
Turns out last weekend, with the snow storm and three days without power, wasn't a great time to have a wood stove sitting there idle and unconnected in my living room!

I called some masons, found someone who seemed good and could get to the job in a couple of days, and he came over last night to expand the thimble. He broke open the brick facade no problem, but then hit a problem straight away -- the fireplace is a heat-a-later (not really sure how that's spelled) and the inside of the bricks was a thick steel that he could barely cut. Worse than that is the fact that once we got through the heat-a-later, the width of that part of the firebox was only 5 1/2 inches across, and we can't get stovepipe in there.

Now I'm faced with two new choices in the on-going saga: 1) have him cut through the heat-a-later metal on the back of the bricks that he's taken out, and then cut and expand the damper in some way that we can get 6" pipe up to the flexible liner (which is here but not installed yet) or 2) brick up the existing thimble, and put in a new thimble, directly into the flue above the fireplace mantle. He's coming back tonight and I said I'd give him a decision. The wife's considering the looks of a higher thimble, but I'd appreciate hearing your thoughts and experiences.
 
Might be cheaper to put the higher thimble in too. But really, so long as there are no combustibles hiding somewhere in there, either should work.

pen
 
I have the same crappy thing. While mine is heart mount. Sounds like this thing just vented into the old fireplace that was just covered up. Sounds like a code violation, or at least dangerous. Go with the higher up thimble, but make sure its sealed beneith it. If anything if and or when you get another stove you wont be limited.

Good luck. Post some pictures if you can.
 
Hmm, never thought of putting up pictures. Here're a few snapshots of the project/predicament:
 

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FirewoodMan said:
I'd keep hacking away at that hole and the box behind. I think a higher thimble that's above your mantel would look pretty bad.
I agree, just remember that a quick fix is gonna be something you have to look at all the time when you get this project done, so do it right the first time and mum will stay happier too.....you should really really consider that steel liner, takes a lot of headaches and worries away, and that stove will perform to it's peak with the proper flue.....you will have way too much space with the existing flue for that stove to operate correctly, it will take all you got to heat that flue up.....with a stainless insulated flue it will be way more efficient......just my 2 cents....
 
just wondering about the price quote.....was the "professional" thinking he was going to get the install? maybe he was trying to drum up some business.

cass
 
Ah now we can see. So you too have a hearth mount. What i did was run into the fireplace to a T which connects to the stainless liner. Nice and easy to clean, plus good on the eyes. If you keep going with the route your doing, you can cut that stuff. A torch is best, i used a sawzall and a few blades and swearing.

Good luck.
 
Weee dogies, what a mess. Ain't heatin' with wood FUN!?

(Guess you at least found out why the thimble diameter was 5", huh?)

Well, in your shoes, I would look to try and enlarge your existing hole/flue by whatever means you can before I'd try and patch that existing hole to move it higher. (Problems foreseen: matching the brick/mortar and who knows if further up you might have the same problem, right?) If there is a damper throat plate that can be chiseled out and extracted, that might give you some clearance. You can always cover the resulting gap at the flue throat below with a block-off plate.

If you wanted a third option, you could cut the existing brick lintel and move the whole fireplace opening up to above the existing thimble hole. Of course, you'd have to replace the lintel with another one to bear the load, and it might be above the top of the existing fire bricks, which might be uuuu-gly. Still, it would allow you to clear out all the unecessary crap and make a nice opening for your connector/liner. Just sayin'.
 
Surely you weren't to code before when you had the pipe entering so close to the mantel? Anybody confirm this. Isn't it 18" to combustibles above black pipe?
 
How was the stove running before this adventure? Assuming you burned a good amount of wood last year, was the chimney relatively clean?
 
Danno77 said:
Surely you weren't to code before when you had the pipe entering so close to the mantel? Anybody confirm this. Isn't it 18" to combustibles above black pipe?

I was also thinking that wood mantel is too close.
 
I had two 90 degrees into a hearth mount. Got rid of them, lots of patching. Put in a new chimney, straight up. "Fortunately" the roof was shot so had that done as well. Stove installer insisted on changing the single wall, from stove to ceiling, into double wall. I wanted the extra heat that emitted from single walls. He said single wall is cheap and doesn't last.

Now I'm happy, cleaning is much easier, less creosote in the double wall, good draft, good looks (even the stove :) )

Just had to bite the bullet and do it right,

Bill
 
ValentineHill said:
After waiting 5 weeks, I finally got my appointment with a chimney sweep today. Hooray, I thought: no more worrying about whatever creosote my be lurking up in the upper recesses of my chimney.

However, the sweep said that I really should reline my chimney with a stainless steel liner. And that wasn't all. Since the 6" collar coming out of the back of my Jotul F400 goes through a 5" thimble into the chimney, he said that I needed (not should, but needed) to expand the thimble to 6". And -- here's the kicker -- the new 6" pipe wouldn't fit in the existing clay lined flue, so the existing flue tiles would have to all be removed before the stainless steel liner could be put in.

The proposed cost? "Three thousand, maybe three and a half thousand."

Obviously I'm not going to do it. But one thing about it did worry me a little -- reducing the pipe from 6" to 5" for the thimble. So I'm asking the group wisdom -- is reducing the pipe size through the thimble an issue or a risk?

Acting on a sweep's advice is like stopping in Newark and asking a crack head for driving directions to Giants Stadium...
 
I think I paid about $2000ish or a bit more to have the liner in my chimney knocked out, a 1/2 inch insulation wrapped 6 inch rigid liner installed and a new thimble location plus a new clean out door put in my chimney last year.

Good luck,
Bill
 
Biff_CT2 said:
ValentineHill said:
After waiting 5 weeks, I finally got my appointment with a chimney sweep today. Hooray, I thought: no more worrying about whatever creosote my be lurking up in the upper recesses of my chimney.

However, the sweep said that I really should reline my chimney with a stainless steel liner. And that wasn't all. Since the 6" collar coming out of the back of my Jotul F400 goes through a 5" thimble into the chimney, he said that I needed (not should, but needed) to expand the thimble to 6". And -- here's the kicker -- the new 6" pipe wouldn't fit in the existing clay lined flue, so the existing flue tiles would have to all be removed before the stainless steel liner could be put in.

The proposed cost? "Three thousand, maybe three and a half thousand."

Obviously I'm not going to do it. But one thing about it did worry me a little -- reducing the pipe from 6" to 5" for the thimble. So I'm asking the group wisdom -- is reducing the pipe size through the thimble an issue or a risk?

Acting on a sweep's advice is like stopping in Newark and asking a crack head for driving directions to Giants Stadium...
Well, I think it's necessary to add a disclaimer that some sweeps know their stuff! BUT being a sweep doesn't mean that you do!
 
The mason's been here for the last three hours, and the job's nearly done. We decided to go with expanding the existing thimble rather than putting in a new thimble above the mantle. He's busted through the heat-a-lator metal wrap, taken out the damper, put 10ft of flexible liner up the flue (money's tight, and I got it for free), and he's now re-bricking up the fireplace front. Thanks for all of the advice -- I'll put up more pictures when it's done!
 
Biff_CT2 said:
...Acting on a sweep's advice is like stopping in Newark and asking a crack head for driving directions to Giants Stadium...

There are a number of trained, certified, professional chimney sweeps and other industry professionals who are members of these forums who would take a dim view of that absurd stereotype...as do I. Rick
 
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