Questions about Double Wall Stove Pipe Installation

[jds015]

Hi All,

I had originally placed our wood stove 24" away from the wall, being ultra conservative until I saw how it ran, and now am placing it at the minimum 18". Everything behind it is not combustible, and clearances are all met and in proper range. My question is, I'm replacing and decreasing my horizontal run double wall stove pipe 6" to attain that 18" rear separation. This is where the question comes in.....On my larger previous existing piece, it had screw holes and I had it attached to the thimble and it felt secure, the screws didn't penetrate the inner pipe where it slid over, but appeared to more or less crimp on it and not slide. The newer and smaller piece has outer screw holes, but not inner screw holes, and even if it did, I'm not sure how effective it really was with attaching? The pipe slides over the inner pipe and thus there is no leakage, and the pipe is literally held up against the thimble by the weight of the stove and it pretty much flush to the wall thimble as it is supposed to be......However, I feel like I'm missing something in that I feel like it should be more secure? The only way for me to get it loose is to literally move the stove, which takes effort. We have a Drolet Savannah, and while it's not huge, it's still a cast iron stove.

I've had a certified sweep check out the install previously and he also gave me the thumbs up to go down to 18" clearance with my setup. He has not seen the pipe connected to the wall thimble though. I just want to make sure things are secure, without damaging the inner pipe and then having leakage. I tried screwing the screws in, but they didn't feel like they did anything. There were no inner holes in the new pipe, while the old one had them.

I had a couple of small burns and there was no problem. This section of pipe is only 12" and is connected securely with screws to other sections, elbows, vertical sections, etc.

Anyway, I'm just looking for suggestions or thoughts in order to ensure everything is secure. It's not moving without me moving it, but still, I am ultra conservative with fire. Thanks everyone. I want to get this situated before we get deep into heating season.

 

[begreen]

It should be secured to the thimble. I would predrill a small tap hole thru the inner liner then use sheet metal screws that are long enough (3/4'?) to screw into the inner layer. Note that all Drolet stoves are steel stoves with a cast iron door.

 

[jds015]

Thank you begreen. Just out of curiosity, how does the screw secure the pipe if it does not penetrate the inner pipe? Other wise, it just more or less crimps up against it as I noted above. This may be all that is needed, I just want to make sure I'm not missing something.

Thank you for clarifying the material of the stove as well. It's heavy regardless, but I want the pipe secure as much as possible. Thank you.

 

[bholler]

Thank you begreen. Just out of curiosity, how does the screw secure the pipe if it does not penetrate the inner pipe? Other wise, it just more or less crimps up against it as I noted above. This may be all that is needed, I just want to make sure I'm not missing something.

Thank you for clarifying the material of the stove as well. It's heavy regardless, but I want the pipe secure as much as possible. Thank you.

You should use screws long enough to go through the thimble. 3/4" usually works

 

[begreen]

Other wise, it just more or less crimps up against it as I noted above.

You don't want to crimp or pucker the inner liner with the screw pushing against it.

 

[jds015]

You don't want to crimp or pucker the inner liner with the screw pushing against it.

I didn't think so, that's why I haven't done anything with drilling holes yet, so my question then is what actually secures the pipe to the thimble then? Since it is double wall pipe, the screws basically just go into the liner of the pipe and hold nothing? If they penetrate that with pre-drilled holes, then they may puncture or crimp the inner liner? The pipe basically slides over the top of the inner liner, much like the rest of the pipe, except all other connections have screws on outer layers to secure them together. This one piece is the only one that doesn't.

 

[jds015]

I didn't think so, that's why I haven't done anything with drilling holes yet, so my question then is what actually secures the pipe to the thimble then? Since it is double wall pipe, the screws basically just go into the liner of the pipe and hold nothing? If they penetrate that with pre-drilled holes, then they may puncture or crimp the inner liner? The pipe basically slides over the top of the inner liner, much like the rest of the pipe, except all other connections have screws on outer layers to secure them together. This one piece is the only one that doesn't.

Thanks again for any response or suggestions. Again, I just want to ensure it is safe.

 

[begreen]

No problem. What type stove pipe is this? And what type thimble? In some cases there is an adapter that joins the pipe to the thimble. Can you post a picture or two so that we can see what you are describing? Maybe include a comparison shot of the ends of the 24" and 18" pipe to show the difference.

 

[jds015]

No problem. What type stove pipe is this? And what type thimble? In some cases there is an adapter that joins the pipe to the thimble. Can you post a picture or two so that we can see what you are describing? Maybe include a comparison shot of the ends of the 24" and 18" pipe to show the difference.

It is Duravent double wall stove pipe. The thimble is the "Through the wall kit" also by Duravent. I'll take some shots this evening and post them. I appreciate the assistance! Once I removed the longer section I'm replacing I have become skeptical as to how secure it actually was?

 

[begreen]

This is the part that joins DVL to their thimble.

 

[jds015]

Here are some pictures

 

[begreen]

Do you already have the adapter ring in place?

 

[jds015]

Yes, it's already in there. The question is what do the screws actually hold the pipe to if they don't penetrate the inner ring to hold in place? The black pipe slides over it like a sleeve now, but again there are no holes inside on the black pipe so the screws don't really do anything. It might be ok, I'm just making sure. Thanks begreen!

 

[bholler]

Yes, it's already in there. The question is what do the screws actually hold the pipe to if they don't penetrate the inner ring to hold in place? The black pipe slides over it like a sleeve now, but again there are no holes inside on the black pipe so the screws don't really do anything. It might be ok, I'm just making sure. Thanks begreen!

As both begreen and i said use longer screws so they do go through and predrill a hole for them.

 

[jds015]

Thanks guys, last night I pre-drilled just enough to get the screws through and it feels secure, and is working well with a warm fire in it.