clay liner in chimney advice

[henkster]

Hi guys,

This question might have been asked before but I haven't found it yet.

I have a clay lined chimney that is 11 inches by 11 inches.
I am going to install a woodburning stove with a 6 inch hole in the top.
I have the pipe for that to go up in to the chimney and it's double walled.

Now is my question can I just stick a few feet of pipe in the chimney and block the bottom of the hole.
Do I need to change it with a 6 inch pipe all the way to the top?

I did talk to a fireplace guy and he told me I could just stick it in there and it should work.

What is thought about this here on the forum.

Thanks in advance.

Henk

 

[pen]

It sounds like you are inserting this into a fireplace?

Regardless, if it is a modern stove, it will really require a large amount of draw (draft) to be caused from the rising action of hot air moving through your chimney. The problem with going from 6 in to 11 in is the surface area of a 6 in round pipe is 28.27 inches. The area of your 11x11 chimney is 121 inches. When hot air moves from a smaller to larger opening the temperature drops significantly. As the temp drops, you will get increased creosote buildup and reduced draft. Both make for bad ju-ju



I have a similar circumstance but not as severe with my chimney. I go from 6 in to 7.25 square. That is not as big as your 4x difference, but is is 2x as large in area. Luckily for me it is close enough that it still drafts well. However, for safety reasons, I am looking into getting the chimney lined in the next year or two.

pen

 

[cmonSTART]

It's also going to be a pain to maintain and clean properly. The best way to do it would be a full liner.

 

[johnn]

there is a math formula for just how much surface area you can increase in size, and i feel you surpass that percentage. Though many installation downloads refer to the installation of a "positive connection" and show you how to do it,,if you read on most models will eventually tell you that the manufacturer requires a "direct connection",,which goes all the way up. (I hope i got that right) As mentioned above,,cleaning will be more involved,since now you will need an access door to get to the creo., that fell down and around your pipe and came to rest on your block off plate or smoke ledge.

 

[CarbonNeutral]

If it's an internal chimney and the cross-sectional area is three times as large, or external and twice as large, then it won't be to code - it just won't draft very well - lots of creosote build-up. Secondly, an insulated liner provides another layer of protection in the event of a chimney fire. I would absolutely run the liner all the way.

 

[ansehnlich1]

I highly recommend running an insulated stainless liner right up and out the top, capped. Anything else and my bet is you ain't gonna be happy.

 

[henkster]

Hi guys,

Thanks for the advice.
I am going to install a free standing wood burning stove it's a warnock hersey 24-acd/50-shw24 made by englander stove works.

It's really nice and I hope to get it going soon.
I know that this will be a pain to install since the builder made it hard to get to the chimney.
the bottom of the chimney is in the corner of the aucove and its recessed in to the corner.

anyway thanks for the advice and i will look in to the liner provided here.

Henk

 

[rdust]

Liner from top to bottom with insulation either wrapped or poured. If the current clay liner is in good shape insulation wouldn't be needed but if it's external the insulation will help with the draft will add to your piece of mind.

When I first started posting here I wanted to use my existing 7x11 clay lined chimney, after taking everyone's sound advice I ended with with a full liner and poured insulation. With an 11x11 flue the liner will drop right down, it'll be a piece of cake!