Expert: Bart Ogden - 10/16/2007

Question
I am in the middle of a new gas furnace replacement.

It turns out the clay lined chimney has a 5" B-vent in it that was NOT used by the last furnace installer. Exhaust went through and around it.

The B-vent was cut/ripped off at the top and a section removed from the bottom. I tried to pull up on the pipe from the top and it did not budge.

From what I can find on B-vent manufacturer sites the B-vent is sized correctly for the new, down sized, furnace.

My current thinking is to cut a clean edge at the top for an extension pipe and flue cap and to add an extension to the pipe at the bottom to get it outside the wall. The pipe also needs to be cleaned. Black granules are visible along its inside.

Can you give me opinions and options for:
- Is removal and replacement probable due to the misuse of the vent and that I can not clean the clay liner around it or the double wall lining?
-----It so do I assume that it will not budge due to weight or being wedged in place and if either or both what technique is used to lever it up? Note there is a 'T' at the bottom that I assume will need to be removed.

- I have never run a chimney brush but from what I see on the net I would use a 8" disk shaped brush for the 5" flue.  Is this brush so flexible that it will bend back for the reverse trip up the flue or do I twist it to get it to collapse or other?

Thank you

Answer
Frank,

The existing piping needs to be replaced at this point.  If you remove the tee and it still won't budge, you will likely need to call a CSIA Certified Chimney Sweep to remove it for you.  They will have special tools to dislodge items from flues.

If you plan on sweeping that flue, you would use a 5" brush, not an 8" brush.  Again, a CSIA Certified Chimney Sweep would be your best choice.

I recommend you contact a local CSIA Certified Chimney Sweep to do some on-site diagnosis of your problem and to offer advice.

You can find a CSIA Certified Chimney Sweep at www.csia.org.

Thanks for using AllExperts.Com and good luck with your project.

Sincerely,
A. Bart Ogden, President
Home Safe Hearth & Chimney, Inc.
Wichita, KS
Voice: 316-265-9828
Fax: 316-265-9890
www.homesafeks.com