jotul c 450 insert flue reduction 6" to 5"

[ozibit juice]

Hello,

I have a jotul c450 insert with a 6" flue, my existing chimney is 6x10.5. a 6" liner will not fit down.


Does anyone have experience with downsizing flue's on a jotul C450 fro a 6"to 5"?

Will this affect draft much? my chimney is 22 feet.


I've been scouring the web trying to see if this will be viable. some people say it might be ok, others say that it will not work. All i know is that i will not be able to fit a 6"liner down there and my choices are either downsize the flue size or sell the insert and get a new one?

Any suggestions/ experiences will be greatly appreciated.

Thanks!


Odin

 

[stoveguy13]

The other option would be to use a ovalized liner that will will allow you to have the right size and have the stove work properly. you can buy an ovalized 7 inch liner ovalized to about 9x4.5 and it will give you the right size.

 

[ozibit juice]

thanks for the reply stoveguy.

I talked with the people at I believe rockford chimneys, and they said that if they ovalize the chimney they will only be able to ship it uncoiled and will cost a bunch with shipping. or is it possible to coil ovalized flues for shipping?

 

[begreen]

Check out M&G DuraLiner. This system is made for your situation and will allow you to put in an insulated liner. They have a full line of oval and round liners.

http://www.dynamitebuys.com/store/cart.php?m=product_list&c=49

 

[Steena]

I had the same problem. I just had the C450 installed about 2 weeks ago, and have a 30 ft. chimney. One dealer told me that Jotul would not guarantee the stove if it didn't have a 6" pipe. The dealer I used said he would personally guarantee the stove, and that he had done this about 20 times with other buyers. The installer used an adaptor to fit the 6" into the 5" pipe that goes all the way up the chimney. If anything, there is probably too much draft, as I seem to use more wood than I expected.

 

[oconnor]

One question - is the chimney inside the house envelope or on an outside wall? Outside flue will be much colder and lose heat quicker Making total draft mite critical.

The five inch didn't work in mine, (two storey inside brick flue) but our house is quite airtight, and I didn't install an OAK. The five will be a significant reduction, but in the end total draft involves more than just the flue diameter. If you must use the five inch, have it insulated to maximise its draft and reduce warm up times.

I would look at the products begreen recommended first. 6 down to 5 is a big reduction. Even a 5.5 is worth some extra expense IMO.

 

[Steena]

My chimney is an outside masonry one, not in the shoeprint of the house lines. The dealer I bought it from was more concerned about having too much draft, with a 30 foot long 5 inch wide pipe, and I would say that it's likely that is what is happening. I don't have any idea of creosote formation yet, so that may be an issue with a tall pipe in the outside chimney.

 

[ozibit juice]

O'connor, the chimney is on the outside of the house.. do you think that your house being air tight played a significant factor? my place is is the opposite of air tight.

There is no question that i would go with a 6'' if i could. Even now i am thinking of ordering a 6" and slightly ovalizing it to better fit, would that would keep the same flue size area?

 

[ozibit juice]

Steena, was there a reason why he didn't want to go with the 6" liner on your installation?

 

[oconnor]

O'connor, the chimney is on the outside of the house.. do you think that your house being air tight played a significant factor? my place is is the opposite of air tight.

There is no question that i would go with a 6'' if i could. Even now i am thinking of ordering a 6" and slightly ovalizing it to better fit, would that would keep the same flue size area?

I suspect that air tightness of a house would have something to do with why a five inch flue would be insufficient in one home, and would draw well in another.

There are a lot of factors that influence draft. My initial poor experience with a five inch flue was also related to my wood not being as dry as it is now.

In the end though, where I was told a 6 inch would never fit, a six inch with insulation wrapped around it is now installed, and it works well with the stove and house I have.

As for size difference, it's all geometry. Some have also stated that a flex liner will flow Less efficiently than a smooth liner of the same size and shape.

There is always the option of having the clay tiles broken out and installing the liner in lieu off the clay tiles.

 

[BrotherBart]

I didn't have room for six inch in either of my chimneys and installed 5.5". The 21' foot one draws real hard and the 34' foot one tries to suck splits out of the firebox. Both in exterior chimneys and not insulated. And it is 24 degrees here right now and they are pulling like vacuum cleaners.

Don't go mashing a six inch liner. Get the 5.5".

 

[ozibit juice]

BrotherBart, im up in the yukon canada where temperatures usually hover around -4 to -40 farenheit for much of the year. does cold weather increase or decrease chimney draft performance?

Oconnor, when you did have the 5" flue in there was the stove still mostly operational and just had smoke pour out when loading? was there sufficient draft for burning?

 

[oconnor]

It was usable. If I had been using the seasoned wood I have now, it wouldn't have been as much of an issue. It occurred during reloads and the stove did not come up to useful temps as easily. It might work, but the drop from a six inch liner to a five should not be taken lightly. It is a 30% reduction in cross section - more than some realize.

The effect of outside temps on draft depends how it effects the air stack and pressure in the house, and where the stove is within it. My basement stove used to back draft badly on startup when it was cold outside, mostly because the house became a better chimney than the flue was.

 

[ozibit juice]

Sweet, thanks for the advice! so im going to be going with a 5" smoothwalled liner, gives you back 20% draft. and will take my chances with the draft issue. ill put a post up here when its installed!