Is SS 316Ti the way to go?

[Geepop]

I have a circa 1990 medium Consolidated Dutchwest fireplace insert connected to a 6" oval 6 foot stainless steel flex pipe. I'm changing the stove over to a Lopi Revere insert or a Pacific Energy Pacific insert. Both are wood stoves. When it gets down to 10 degrees or so the Dutchwest is not quite adequate and we do get below zero some nights where I live. (With the climate changing there are fewer cold nights than we had 20 years ago)!

I figure now would be the the time to also change over the way the stove is vented. I have an external brick 20' lined chimney with two 8 x 12 flues. I've got qot quite a bit of creasote showing around the flue cap for the stove. The other flue is used soley for the oil boiler. So here is what I need some group wisdom on:
Is 6" x 20' round stainless 316Ti .006 flex the best way to go?
Should I wrap the flex with 1/2" high heat insulation?
What brands give the most bang for the buck?
How do I seal off the bottom of the chimney behind the stove so that I'm not loosing heat from the house?

I'm retired so money is a concern yet so is safety and limiting future problems.
Any suggestions will be much appreciated.

 

[Geepop]

I'm also wondering how to clean flex pipe for an insert install since there will be a little S curve in the area where the damper was.
Does the creosote if any fall down into the stove?
Will the brush stop at the "S" ?

 

[Wet1]

On that note, do the ridges in the flex pipe hold more creosote? I would think so (I don't know). Also, does it come clean with a brush???

 

[RAY_PA]

me wonders the same, as I am very close to doing my install.

 

[Geepop]

Hopefully someone in this forum will have an opinion or two.

 

[webbie]

Rigid stainless is 4x as thick as flex...sometimes more! If chimney is straight, this may be a better way to go. 304 is fine for wood.

Insulation helps if chimney is exterior - or if chimney does not meet current code.

 

[TruePatriot]

Craig,

I have the same setup (exterior chimney, two flues) as the O.P., except mine is 28' high and I will be cutting through the chimney with a "T" and thimble.

Re: this:

Rigid stainless is 4x as thick as flex...sometimes more! If chimney is straight, this may be a better way to go. 304 is fine for wood.

If the chimney is fine, clean and to code (which I'm sure my sweep will confirm) is there any inherent advantage to going with the rigid liner? I understand 4x thicker is good, but don't most SS/ti flex liners come with a lifetime warranty?

Which is easier to install?

How long are the rigid sections?

How are they joined together--do you screw them together at the top of the chimney, and stuff them down?

Wouldn't it be more difficult to apply 1/2", high-temp. insulation to individual sections, as opposed to flex liner?

Sorry to pepper you, and I hope these questions are of interest to the O.P.

Thanks again.

Peter

 

[JimmyMood]

I'm also wondering how to clean flex pipe for an insert install since there will be a little S curve in the area where the damper was.
Does the creosote if any fall down into the stove?
Will the brush stop at the "S" ?

Have you installed the liner yet? What sort of radius are you trying to make the S bend around? After uncoiling my liner and stuffing down a reasonably straight chimney, I found that "flexible" is a relative term. I think any bends smaller than a couple foot radius are going to be tough without kinking and mangling the liner.

 

[Wet1]

304 is fine for wood.

What about for coal?

 

[Geepop]

JimmyMood I haven't installed the liner yet. I"m waiting for the PE Pacific insert to arrive and then will change everything over at the same time. Currently thereis a 6" oval 6 foot long running from the back of my consolidated Dutchwest up into the chimney.

 

[Geepop]

TruePatriot I have wondered also about the questions you have. It's the portion where I will have to run some pipe through where I long ago removed the damper that I think may present a problem.

The stove dealer says they often have to "ovalize" the flex pipe some with a piece of wood and some pressure before inserting to get it through this area and then they squish end back to round with their hands to connect it to the top of the stove.

I have seen nose cone pullers that can be attached to the flex pipe to help get it through difficult areas. My dealer doesn't have one since they don't use them. On the web I've seen metal ones for about $25-50 depending on source. I'm thinking a one time use one might be able to be fabricated out of a funnel with part of the spout cut off. If it's a plastic funnel that may offer less resistance than a metal one. Problem will be in secure attachment of rope to funnel.

The dealer also said they do not insulate the SS flex if the chimney is in good condition and has a tile liner. Dealer also said they do not fabricate a block off plate at the bottom of the chimney behind the stove. They stuff lots of unfaced insulation around the pipe to seal off that area.

Dealer showed me some chimney brush rods that are about $15 per 4-5 foot section that are very flexible. Can be bent to about 60 degrees. Hpe it would make it through the "S" but that may depend on how sharpe those bends end up being.

I would think it would be more of a job to use rigid pipe but I'm not sure. I would guess that the rigid is preferred?

 

[begreen]

Geepop, is this an interior or exterior wall fireplace?

 

[Geepop]

Exterior. Two 8 X12 flues. one for fireplace other for furnace.

 

[begreen]

There are very few installers that are concerned about wood consumption, they properly are concerned about safety and getting the job by bidding competitively.

I would insulate the liner and include a proper block-off plate. Maybe insulate behind the insert too. The object is to try to keep all the heat the stove is creating inside the house and not heating the outdoors.

 

[Geepop]

That's kind of what I'm thinking too. If you insulate the liner cutting pieces and sealing with foil tape what's the life expectancy of the insulation? Instead of wrapping in sections can you do one continous piece wrapping on a diagonal? I thought the pipe wrap was more for creosote? What would you use for metal for a block off plate? Where would you get this metal?

 

[Geepop]

Got to leave for a few hours.

 

[begreen]

That's kind of what I'm thinking too. If you insulate the liner cutting pieces and sealing with foil tape what's the life expectancy of the insulation? Instead of wrapping in sections can you do one continous piece wrapping on a diagonal? I thought the pipe wrap was more for creosote? What would you use for metal for a block off plate? Where would you get this metal?

They make liner insulation in sleeve lengths or insulation can be poured around it. Yes, the insulation is for creosote reduction which I recommend for an exterior chimney in a cold climate. There will be a huge differential between the flue temp and the outside temps in the dead of winter in your area.

Block off plate instructions are here in the wiki area. Just use regular sheet metal and kaowool insulation. There are variations that other folks have posted here in the forums if you search for them.

https://www.hearth.com/econtent/index.php/wiki/Why_damper_seal_is_needed/
https://www.hearth.com/econtent/index.php/articles/making_a_block_off_plate/

Here’s links to threads that have some pictures of the block off plate installation.

https://www.hearth.com/talk/threads/11697/
https://www.hearth.com/talk/threads/9630/

 

[Wet1]

I have a 30-35' unlined flue, it's an interior chimney. I believe it's 8"x8", or possible wider, but I'm pretty sure it's only 8" wide in one dimension.. What do you guys suggest I use?