Quote Originally Posted by gravity View Post
I attached to pictures. If you go by the code, the chimney adapter installed on the OP furnace is illegal because it retards the flow of exhaust gases. If you had a combustion analyzer you could verify this in 5 minutes.

Also, another document that states the code book is consensus and has never been field tested...

Hmmm.........i think i would believe field tested data with my analyzer then some theory in a book.
The code book in my country isn't based on hopes and dreams like yours I guess....
I wasn't suggesting this so called chimney adapter. I believe a properly sized chimney liner in the masonry, then transitioning to b-vent to the furnace is the best and only way to go