Forcing a 6 inch SS liner into a clay lined chimney or reducing to a 5"

[mark10]

The forum has been very informative and I have been promoting it to others.
This site will save peoples lives

My situation: I have an 1800 sq. ft split level house. I removed my old EBI insert from Cambridge, Ontario ( no fan/heatilator ) 7" flue

No direct connection from the flue to the chimney, creasote on the sides & top of the fireplace & smoke chamber to the chimney, missing sealant/rope on the windows producing gaps

Wishing to upgrade: Current FP size is 36"w x 24"h x 22" deep with the rear FP wall at 25 " wide
The FP floor is 1" lower than the brick lintal ( is that the right word to describe brick lip that sticks out of the front of the FP about 1 ft off the floor ?)

Can I retrofit by cutting out the 7" flue & retrofitting with a 6" flue
The chimney is lined with clay that is 6" x 10" on the inside
My concern is that a 6" SS flex liner may fit into the 6" x 10" space with some "force" that could damage the liner by seperating the spirals creating cracks that could cause problems with leakage in the future.

Or I could retrofit with 5" flue...this could be unwise because the volume of the hearth/combustion chamber would be choked causing smoke & insufficient venting?

Do I REPLACE WIT A NEW INSERT ..if so ...can I REDUCE the 6" flue to a 5" SS flex liner if a 6" liner is too tight to fit into the 6" x 10" space.

Thanks for your help.

 

[Todd]

They also make a 5.5" flex liner. I have the same sized clay flue as you, and I couldn't get a 6" liner down, so I went with the 5.5", and it drafts great!

 

[Todd]

One other thing,
If you ovalize a 6" liner doesn't that reduce the inside diameter? I thought we had a thread about that awhile back. Round drafts better.

 

[webbie]

The forum has been very informative and I have been promoting it to others.
This site will save peoples lives


Do I REPLACE WIT A NEW INSERT ..if so ...can I REDUCE the 6" flue to a 5" SS flex liner if a 6" liner is too tight to fit into the 6" x 10" space.

Thanks for your help.

First of all, if chimney tiles are in good shape, you may not have to line chimney to the top! Just a 5 foot flex tube slightly oval to go through the damper and up to near the first flue tile will do.

If you are going to line, you have multiple choices.

1. Rigid Pipe - slightly oval - since this pipe has a much thinner profile than the flex, it might fit in a little easier - you would still need some flex at the bottom.

2/ Oval Flex - 5.5 or 6 - just slightly oval, like about 5" wide should fit down.

3. Rectangle flex - some companies will custom make the flex for you something like 5.5 x9 OD, which will surely give you the largest flue cavity. They may also have rectangle rigid pipel