Do I need a stainless steel liner for my chimney?

I got some answers about the SS vent from several different sources. Keystoker told me that 316SS is what is recommended. A sheet metal fab house I contacted said that 304SS will start to chip and pit in several years and you will start getting pinholes in it. They also said the 316SS will resist the corrosion from the coal boiler's exhaust. Several people, including Keystoker, told me that you can use Galvanized or stove pipe, but said you have to check it every year and may need to replace it after a year or two. I'm not up for the idea of replacing the vent pipe every year or two so I decided to go with the 316SS. There is a line of chimney liner called Flex King, made it Pennsylvania, that is 316SS. They sell kits or just the parts you want. There are also insulation kits they sell to go with the liners if needed. They were pretty helpful when I called with questions. The tech even went so far as to find me a 10' length of 4" diameter liner because I didn't need 20'. It saved me about $110.00 and the aggravation of storing excess material. No way I would throw away that much 316SS at that cost. This is just the way I decided to go, there are certainly different factors to consider and various opinions on this, but I don't want to add more work that necessary and I want to make sure my wife feels secure with this.
Mike

Just starting out, I put a used keystoker in my basement next to the furnace ( thanks matt ) and ran galv. 6" flue pipe up and over to the power vent.
A buddy has some left over flex stainless flue liner rated for coal. I know this is for inside a mason. chimney but could I use it for my flue inside the house.
It would come out of the furn. up approx. 5 ft. across the ceiling approx. 14 ft to the power vent.
Also what kind of flue temps should i expect?
Thank you.

The whole reason for chimney liners and the reason they are in the code books is house fire prevention. In a wood burning situation a chimney fire is fairly common occurrence. With a SS liner installed or class A chimney the inside of the chimney can get 1000 degrees or more with raging flames and (supposedly) not burn the house down. If it gets to the point that the the fire department is called they can close off the bottom of the chimney and seal off the air and the fire will go out. Now if you have a chimney fire in an unlined chimney it will suck air from all the loose mortar joints, cracks in the bricks, spaces between the terracotta tiles and the fire will be raging hot. Closing off the stove won't help as it is sucking air everywhere. The chimney fire can get out of control and burn your house down, costing the insurance companies big $$$$$$. With just 4" of brick between 1000+ degree flames and your old wooden wall or an attic full of flammable plastics your house will burn to the ground. Some people decide not to clean the chimney so they can have an "accidental fire" on purpose and collect some cash. It happens more than you might think. To prevent this, and also saving ignorant homeowners from themselves, from sketchy contractors, and saving the insurance companies money the powers that be came up with the stainless steel one piece liner solution and every chimney "expert" recommends them. So bottom line, if you burn wood get a class A chimney or line your terracotta flue with a one piece liner. If you burn only coal then use bricks.

My question is a slight variation on this thread. I have a Wood stove fireplace insert with SS liner up a 16' tall chimney. I'm thinking of swapping it out for a LL sidewinder. Can I use the SS liner as-is, or do I need to do something different? Thanks!

You can use the SS liner as is, but clean it out, or get it cleaned, so any accumulated creosote from the wood fires won't clog the chimney.

Greg L.

For 2+ months I was able to heat most of my 3,000+sf home on nut coal with my harmon magna-fire elite insert, and smile with glee as the propane truck passed my house.
Then, out of the blue she stopped working well. I had virtually no draft. Came to discover that low barametric pressure, humidity and wind direction was an issue.
I have a very large 30+ ft class A unlined chimney, that needed just the right enviornment to preform effectivley.
Just had an insulated stainless steel liner installed, along with a small terra cotta extension to the flue ( have three flues at the same height above the roof that were competing for draft ) and the harmon was humming last night with outside wind gusts up to 60mph.

Can now laugh at the propane truck again.

I'm alittle confused about these SS chimney liners. I've had a coal boiler in my basement for 2 years now. It has a 5" vent on it. I go from the 5" vent, to 6" pipe, then to a 24' clay lined chimney built in the mid 40's. The chimney was oil heat up til 2 years ago. When I installed the boiler, I cleaned the chimney. I noticed several areas where clay liner had broken out over the years. The block and brick is in great shape, it's just the lining that looked somewhat unhealthy. Over the last two years nothing had changed. About a month ago, I had to replace the chimney cap and the clay right at the top is crumbling on the down wind side. I understand it's a coal acid and water attack. Is this true? Also, how do I fix it? I been considering the SS flex liners in a 5" dia. with insulation. Is this a good move? What about longevity and ventilation?

Most likely it's water freezing and heaving the liner each season. Sounds like you may need to line that sucker, or have it done with refractory mortar by a pro.

Another reason to line chimney is carbon monoxide (CO) infiltration. Should one have a flue that has voids one could conceivably get CO into the living quarters. Have any suspect flue inspected by a pro, or run the risk of CO poisoning, among other things.

flue is under negative pressure. co infiltration due to gaps in brick is a myth. there's only going to be a problem if there is a draft reversal or no draft, in which case you'll have co coming out of the stove/pipe joints like many posts on this site show, in which case a few small gaps in the brick is the least of your worries. it's a common misconception used to convince people to buy liners from a liner salesman aka "chimney professional"

in regards to the crumbling flue tile; all clay tile is not created equal, rarely some is made poorly from inferrior materials. the crumbling liner is nothing to be concerned about, brush off the dust and continue about your business

I was told in New York State it's the Code to have a chimney liner for a coal fired stove. I have a conventional tile/brick chimney and am looking into get a Hitzer insert. I thought I could use my existing chimney to vent the stove ?
thanks
Jim

yes, "code" requires that there be a liner- the liner can be any material from firebrick to clay tile (most common) to stainless steel. regardless of code, a chimney venting a coal-fired appliance in decent condition does not need any form of liner. your clay tile liner will work just fine AND is ok with coal according to "code".

I talked to an installer (different one) in my area and he said a SS flue liner may/is not be required by code but they highly recommend one based on the efficiency. He claims the stove will run more efficient if you continue the stovepipe up to the top of the chimney verses the 5 ofr 6 fett required to get by the damper. (how ?) In addition, he says that the clay tile will rot out faster because the flue gas will not be hot enough to stop consolation. I am suspect of this.. how much cooler could the flue gas be ? Any of this make sense ? Should I line my chimney with SS ? What are your thoughts ?
I am looking at a Hitzer 503 or something similar to insert into my fireplace opening and I would like to use my existing masonry chimney which is about 22 feet long.
Thanks !

the flue gas does cool when it goes from a smaller liner to a larger one. with coal this is not an issue because of the very small amount of moisture present, there will be no condensation. clay tile will far outlast stainless there are chimney pots in england that are in almost perfect condition after having been exposed to very high sulfur/chlorine coals for well over 100 years, if the tile liner was made properly- and most are- it should last over 100 years with coal vs. 10ish for 316ti stainless (pinholes will likely develop by this time). stainless liners arn't doing anything for "efficiency". what they may do, especially if insulated (besides draining your pocketbook) is offer an increase in draft; how much? well that depends on a number of factors and sometimes they will make virtually no difference. the question is based on what you have there in place currently, is the draft likely going to be enough? that's why it would help to know:

is your chimney on the interior or exterior of your house? how large is the flue tile currently installed in the fireplace chimney?

I agree with Berlin on the superiority of a clay based liner,which is why

all large chimneys use it for the interior surfaces.Coal gases are slightly

acidic and the free chlorine in them will even corrode 316* stainless

steel in a short time.There was even a problem with gas furnaces that

are near the laundry area in a house basement where the combination

of humidity and chlorine destroyed some the heat exchangers in these

units,solved mostly by using outside air for combustion.

Probably the best liners are the round liners with the bell mouth up that

can be cemented together with fire cement to make a free flowing inner

surface that will draft as good as any stainless steel.The round shape has

much better flow characteristics than more common square or rectangular

flue tiles.The only drawback is the increase in the need for more space for the

bell end,but that extra space can be an advantage in that the flue doesn't

touch the outer brickwork so is much less likely to crack,and that space can

be easily filled with vermiculite or other insulating materials for even a better

drafting chimney.

A chimney built this way will last many centuries with only minor exterior re-

pointing and repairs from the weather damage.

BigBarney

Berlin wrote:the flue gas does cool when it goes from a smaller liner to a larger one. with coal this is not an issue because of the very small amount of moisture present, there will be no condensation. clay tile will far outlast stainless there are chimney pots in england that are in almost perfect condition after having been exposed to very high sulfur/chlorine coals for well over 100 years, if the tile liner was made properly- and most are- it should last over 100 years with coal vs. 10ish for 316ti stainless (pinholes will likely develop by this time). stainless liners arn't doing anything for "efficiency". what they may do, especially if insulated (besides draining your pocketbook) is offer an increase in draft; how much? well that depends on a number of factors and sometimes they will make virtually no difference. the question is based on what you have there in place currently, is the draft likely going to be enough? that's why it would help to know:

is your chimney on the interior or exterior of your house? how large is the flue tile currently installed in the fireplace chimney?

The chimney is on an outside wall I am guessing (by visual inspection) it about 8x8 rectangular shape. The chimney was built in 1940 and it has been maintained very well. We burn about 2.5 face cords of wood every year and I have it cleaned and inspected every 18 months or so.