Class A chimney recomendations

I have my stove down the basement and now it's time for the chimney purchase and install. It's a 7"flue and I will be using double wall stove pipe to exit the basement due to clearances with the floor joists, 10" clearance. The dealer I bought the stove from, who also burns coal, recomends the top of the line SS class "A" from http://www.olympiachimney.com/products/cat/VCAA/. He says the heavier gauge is what I want. I don't mind spending the money on the best as long as there is a large enough difference in the durability. the dealer thus far has been nothing but helpful and a great guy to deal with so I have no reason to doubt what he says is true, I just want a second opinion I guess. So what say you, is this what I need.

I see on the web site it says "Coal warranty - Forever Warranty with 316L inner wall pipe". Forever should be long enough.

Do a search on the forum for numbers like 316 and 304. I don't know what they mean, but I know there have been postings describing the various stainless grades.

My recommendation is to steer clear of anything stainless when using coal, unless you absolutely have no other possible choice. My reasoning is this: - what good is a lifetime warranty when you have to climb up there & replace the thing when it fails in 2 ... 3 ... 5 (if your lucky) years? Nice to know your covered ... but the fact remains that stainless steel + damp flyash = pinhole central. Some sooner than others.

Here's some extreme close-ups of my 304 SS connector pipe, & my 304 SS hot water coil, both after ONE summer in a damp basement with flyash stuck to them:

Bruce M wrote:I have my stove down the basement and now it's time for the chimney purchase and install. It's a 7"flue and I will be using double wall stove pipe to exit the basement due to clearances with the floor joists, 10" clearance. The dealer I bought the stove from, who also burns coal, recomends the top of the line SS class "A" from http://www.olympiachimney.com/products/cat/VCAA/. He says the heavier gauge is what I want. I don't mind spending the money on the best as long as there is a large enough difference in the durability. the dealer thus far has been nothing but helpful and a great guy to deal with so I have no reason to doubt what he says is true, I just want a second opinion I guess. So what say you, is this what I need.

I wouldn't waste money on the "best" as it will only last slightly longer than the worst, which isn't long. Go with the cheapest 316ti chimney you can find. Or you could do it right and save money - spend a weekend or two and throw up a block stack with an 8/8 tile liner; If you want inexpensive and decent appearance, "stucco" it in the living spaces and use block the whole way. A masonry stack with tile flue will last a lifetime.

Few initially believed the problem with stainless flues was as serious as it is when I first mentioned it a few years ago, however, I've seen multiple failures personally, and a few already on this site. As time goes on and more people on this site and elsewhere more thoroughly inspect and/or have serious failures with their flues, I fully expect this problem's significance to be apparent to everyone. Stainless (of any common alloy or thickness) doesn't hold up with coal, it shouldn't be used, and it may pose a serious safety hazard in certain circumstances.

Bruce M wrote: It's a 7"flue and I will be using double wall stove pipe to exit the basement due to clearances with the floor joists, 10" clearance.

You can accomplish the same thing with single wall and use spaced protection on the ceiling. Much less hassle and expense especially when you take it down to clean it. You also gain the radiation of the single wall pipe. Unless it is a really large stove you could probably use a 6 inch flue for greater savings.

Thanks all for the replies. This new info puts a damper on my flue ideas, dumb pun intended. Ill look into what is involved in doing a masonry chimney.

go with a block and flu chimney outside and use a double or triple wall pipe at the ceiling for your 10" clearance, or if possible lower the thimble to 18" below the ceiling following most codes. It will have a "lifetime warranty" also,but you never have to replace it.

Dennis wrote:go with a block and flu chimney outside

Outside chimneys sometimes stay too cold and don't develop adequate draft, especially on the cold north side of the house where they don't get sun. That's one advantage of the insulated class A chimneys, they stay warmer.
"Nothing is easy"

SMITTY wrote:... stainless steel + damp flyash = pinhole central.

So why not some sort of liner for the stainless class A chimney? Is there an epoxy paint that would take the heat and also stand up chemically to the fly ash?

After reading this post it's making me rethink my choice. Thought a good stainless steel chimney would last for several yrs without issues. So if stainless doesn't hold up why not just use black stove pipe?

Wiz wrote:So if stainless doesn't hold up why not just use black stove pipe?

My black stove pipe, not even the high quality stuff, is still in good shape after five seasons. But that's indoors, of course. I think the original poster in this thread was looking for an (outdoor?) chimney solution.

rberq wrote:

Wiz wrote:So if stainless doesn't hold up why not just use black stove pipe?

My black stove pipe, not even the high quality stuff, is still in good shape after five seasons. But that's indoors, of course. I think the original poster in this thread was looking for an (outdoor?) chimney solution.

Oh, I didn't realize it would make a difference on chimney mostly on the outside of building. Still much to learn.

Black stove pipe you ask? This is black stove pipe after one summer: (masonry is the only way to go )

SMITTY wrote:Black stove pipe you ask? This is black stove pipe after one summer

WTF? When the tide rises, do you have salt water flowing through your cellar.

The different service life for any pipe compound has a lot to do with the presence of moisture. My SS pipe and chimney is good so far after 12 seasons with no special treatment what so ever. Dry fly ash will do little damage but give it some moisture and then acid forms. It's acid that does the corrosion and pitting when it comes in contact with a reactive surface. Smitty can attest to that - after seeing some of his basement water shots, I think he should open up a bottled water business