Confused about chimney liner

Confused about chimney liner

PostBy: ErinMarie On: Tue Sep 25, 2007 8:16 pm

Hi -

My husband and I want to get a coal stove. Last year we had the chimney swept and inspected and the guy said that our liner and chimney were in good shape if we wanted to get a coal or wood stove then or even the next year (which would be now). Just to be safe, we had another guy come out from another company a couple weeks ago and he gave the same report - liner looked great and chimney was in good shape for getting a stove.

They did both mention that the liner does not come all the way down to where it would hook up to the stove itself, but did not indicate this was a problem we should resolve . They both gave the "thumbs up" for getting a stove.

The guy at the stove shop said that this is no good - that they need to hook up with a T-piece into the liner directly. We haven't yet figured out how high up the liner is from where the hookup would be. But the guy at the stove shop basically said we needed to get the chimney relined.

Is this true? Does the stove pipe have to hook directly into the liner? I am sure that would be ideal, but is it a serious safety issue if it is not?

If this was such an issue, why did neither of the chimney guys bring it up or suggest we get the chimney relined?

I'm new to the world of stoves...so I realize this might be a stupid question. But I would be stupid if I didn't ask, so I'm asking. Thanks for your help.
ErinMarie
 
Stove/Furnace Make: Harman
Stove/Furnace Model: DVC-500

PostBy: coaledsweat On: Tue Sep 25, 2007 8:36 pm

How tall is the chimney, what is the liner made of? What is the flue size and is this installation into a fireplace or a stove thimble?
coaledsweat
 
Stoker Coal Boiler: Axeman Anderson 260M
Coal Size/Type: Pea

PostBy: ErinMarie On: Tue Sep 25, 2007 10:06 pm

coaledsweat wrote:How tall is the chimney, what is the liner made of? What is the flue size and is this installation into a fireplace or a stove thimble?


Thanks for your help - as you can tell I am very new to all of this.

The chimney itself spans 3 floors and goes into the basement. My husband said that it's probably about 40 feet long.

The liner is 6" stainless steel.

It is installed into an opening for a stove pipe, not a fireplace.

Thanks so much for your help. I appreciate it very much.
ErinMarie
 
Stove/Furnace Make: Harman
Stove/Furnace Model: DVC-500


PostBy: e.alleg On: Wed Sep 26, 2007 7:34 am

If the liner is cemented in place, meaning that no gasses can get between the liner and the bricks, you should be fine. Fire Code requires the liner to be one continuous unit from the stove to the top of the chimney, so think about what is touching the unlined chimney in the event that you burn wood and have a chimney fire. If your chimney is straight, no offsets, it is easy to install a new liner as long as you are comfortable working on the roof. You can buy a whole kit of top quality stainless liner on Ebay for about 1/2 price of the local fireplace stores.
e.alleg
 
Stove/Furnace Make: EFM
Stove/Furnace Model: 520

PostBy: coaledsweat On: Wed Sep 26, 2007 8:00 am

A 40' chimney doesn't need a liner for coal if it is in decent shape. You will need a barometric damper.

How old is this chimney and does it have terra cotta flue tiles or is it brick inside and out?
coaledsweat
 
Stoker Coal Boiler: Axeman Anderson 260M
Coal Size/Type: Pea

PostBy: LsFarm On: Wed Sep 26, 2007 11:07 am

Hello ErinMarie. If you can check on a few items, we can help you with your concerns: Take a small mirror and look through the chimney-pipe that protrudes into your room [the thimble]. Look up the chimney and see if you can see the bottom of the flue liner.

A normal instalation would have the thimble, which is usually a 'TEE' connected to the bottom of the liner-pipe, and the other downward facing end of the 'TEE' going down to an area that has a clean-out door for accessing and removing any ash accumulation.

IF your 'TEE' is hooked to the bottom of the liner, you are good to go. If there is a gap between the 'thimble or Tee', this gap should be sealed with cement or mortar, providing a sealed passageway from the stove's flue-pipe to the chimney liner.

The question has been asked if your masonry chimney has a clay liner, or is just bricks. The reason for this is at least partially to figure out why the chimney even has a liner. A masonry chimney with a terracotta [clay] liner is a VERY good chimney, especially if it is 30+ feet high like your's is.

The liner that was installed may have been an attempt to reduce creosote accumulation from a wood-burning stove, OR, and this is most important: the liner may have been installed to correct a bad, leaking brick shimney.

Sometimes a liner is installed simply because it was recommended, not because it was needed. Many stove-sales places will recommend a liner because this way they are sure that you will have a good chimney, without even asking for an evaluation of your existing chimney. The sales person's word becomes 'gospel' even though is was based on good intentions instead on good evaluation of your chimney.

Take a look into the chimney through the flue and tell us what you can see, or ask the chimney cleaning guys to tell you if they can see if the chimney liner is sealed with mortor or concrete to the inlet thimble.

Hope this makes sense and helps.

Greg L.
LsFarm
 
Stoker Coal Boiler: Axeman Anderson 260
Hand Fed Coal Boiler: Self-built 'Big Bertha' SS Boiler
Baseburners & Antiques: Keystone 11, Art Garland

PostBy: kwhh On: Wed Sep 26, 2007 11:23 am

Hiya, Erinmarie's husband here.

The Flue is terra cotta. It has brick masonry around it. It appears both flues (one for the basement Oil Water Boiler, one for the main floor living room are 6" terra cotta all the way down. The oil furnace has a flexible lining that was installed in 2002 (we know because we have the reciept from the previous owners).

As for the over all age, I don't know. But the house appears to have had a coal octopus at one point (from the duct work and coal room in the basement). As near as I can tell, the chimney is as old as the main building (from the setting, the floor jousts acnhored in / with the chimney are higher than therest of the house). There is some contorversy as to the exact age though. We have a field stone basement, but depending on the document, say 100 years old.

But the terra cotta we can see from the stove entry point looks fine (and as Erin said, both sweeps agreed it was in good shape.

  • There are clean outs in the basement, and the second sweep said that would pretty much eliminate the need for a full chimney sweep as the fly ash could settle in the basement, clean that out, clean out the horizontal part of the stove pipe, and we'd be good. Is this sound advice?
  • Is it possible to bridge the bare area bewteen the stovepipe entrance and the stainless lineing without lining the whole chimney?
  • Now, if there isn't a liner with a T, how dow the stove pipe connect to the chimney? Doesn't it need to be air tight? (The hole in the chimney is 8", and is about very roughly 18" from the front of the mansonry to the flue. The Hole in the Flue is also appears to be 8".)
kwhh
 

PostBy: kwhh On: Wed Sep 26, 2007 11:55 am

Take a look into the chimney through the flue and tell us what you can see, or ask the chimney cleaning guys to tell you if they can see if the chimney liner is sealed with mortor or concrete to the inlet thimble


No, it is not. Well, we can pull the thimble out of the wall.
kwhh
 

PostBy: coaledsweat On: Wed Sep 26, 2007 11:56 am

kwhh wrote:
  • There are clean outs in the basement, and the second sweep said that would pretty much eliminate the need for a full chimney sweep as the fly ash could settle in the basement, clean that out, clean out the horizontal part of the stove pipe, and we'd be good. Is this sound advice?
  • Is it possible to bridge the bare area bewteen the stovepipe entrance and the stainless lineing without lining the whole chimney?
  • Now, if there isn't a liner with a T, how dow the stove pipe connect to the chimney? Doesn't it need to be air tight? (The hole in the chimney is 8", and is about very roughly 18" from the front of the mansonry to the flue. The Hole in the Flue is also appears to be 8".)


Perfect.

Pull the liner.

Connect the stove to the thimble, the stovepipe should not protrud into the chimney. I would neck the thimble down to the size of the stovepipe of your appliance.

Your all set to stay warm.
coaledsweat
 
Stoker Coal Boiler: Axeman Anderson 260M
Coal Size/Type: Pea

PostBy: LsFarm On: Wed Sep 26, 2007 12:45 pm

In addition to coaledsweat's replies I would add this:

Yes the flue pipe to the chimney flue should be sealed. This can be done with regular mortar [bag of redi-mix, a few $] or with some other similar sealant. Your tall chimney is going to pull very strongly [strong draft] and will be pulling air from the inside of the house through any gaps in the flue up the chimney.

The exception to this would be when you are first starting a fire, and the air in the chimney is not rising much yet, or if the outside temperatures rise a lot and causes the draft in the chimney to drop. Under these cirucumstances you may get some leakage into the house, and this should be avoided, so seal the flue pipe to the masonry.

As coaledsweat stated: Make sure that the thimble does not protrude into the clay chimney, if it does protrude too far it will block the air flow and provide a ledge for flyash to accumulate on.

You could try to seal the gap around the liner at the bottom where it ends above the thimble with hand-applied mortar, but this is pretty difficult to accomplish. [you will be defying gravity with a putty-like sealant] Like coaledsweat stated, you can pull the liner and use the existing terracotta liner, providing it is in good shape.

Hope this helps.. Greg L

.
LsFarm
 
Stoker Coal Boiler: Axeman Anderson 260
Hand Fed Coal Boiler: Self-built 'Big Bertha' SS Boiler
Baseburners & Antiques: Keystone 11, Art Garland

PostBy: Bob On: Wed Sep 26, 2007 1:37 pm

A possibility as why the chimney has a stainless liner if the clay liner is in good shape -- in 2002 perhaps the oil burner was replaced and there was some issue with the draft on the new oil burner. Standard procedure in such a case would be to install a liner.

How do I know this--in 2005 we replaced an oil fired hot air furnace in a 45 year old house with a lined masonry chimney that was in good condition and had worked fine with the 35 year old oil fired furnace. The new furnace had draft issues--explained by the installer to be a byproduct of the higher efficiency of the new furnace--and we installed a liner. Problem solved.
Bob
 
Stoker Coal Boiler: AHS 130
Coal Size/Type: Pea/Anthracite

PostBy: e.alleg On: Wed Sep 26, 2007 8:33 pm

Bob makes a very good point. On a furnace with high efficiency the flue gasses won't be very warm and a cold chimney doesn't like to draft very well, as evidenced when starting a new fire and everything is cold and smokey. I don't think that is ever a problem with coal or wood.

The danger in loose mortar/bricks or lack of a steel liner in a masonary chimney is chimney fires. In the event of a chimney fire, if the chimney is lined all the way, all you have to do is shut off the air at the thimble and all is good. The heat is contained and the fire goes out. If there are loose bricks allowing combustion air into the chimney in the case of older unlined chimneys you could have a burnt down house or worse, so the insurance companies and governing agencies basically made liners mandatory for all chimneys. If you don't ever burn wood and start with a clean chimney you don't have to worry about a chimney fire, fly ash isn't combustable.

Enjoy your coal and your extra warmth and money.
e.alleg
 
Stove/Furnace Make: EFM
Stove/Furnace Model: 520