Hello,

I am planning on purchasing a chimney cleaning brush for my furnace chimney. It is brick, with terra cotta lining (original), 50 years old..

The lining measures 6.5 inches across, measured at the roof

Should I purchase a 6" or 7 " brush (there are no 6.5 inch brushes.

I get the impression from researching, that this is considered a 6" lining, so a 6" brush is the way to go. Am I correct ?

Also, would you recommend metal or plastic (polypropylene) ?



And, bonus question, there is no cap, never has been. Some people say that is fine, as the terra cotta and brick will absorb the minimal rain that enters, others say that a cap is essential.

Opinions ?

Where I come from and most places its not proper code to run furnace vent into an existing chimney,, so I can`t give advice on chimney cleaning

Thanks for the answer,

To clarify, this is the chimney for the furnace, built for the furnace. Chimney starts on the basement floor, goes up to and out the roof. A metal pipe with damper connects the furnace (oil fired) to the chimney. This is not a vent from a high efficiency furnace, but actually the heated flue gases, produced from burning oil...

Hope this clarifies