Chimney Support Box Issues- help!

[Mt Ski Bum]

Hi all!

I have been having issues with controlling the draft/airflow in my Avalon Pendleton due to my chimney support box not having a stove pipe adapter, resulting in significant air gaps between the side of the stove pipe shoved into the hole & the edge of the box (crude rendition of set up made in MS Paint attached, will try to get actual pics later). It is labeled as an Amerivent 6 FB-CS.

Is there an easy way to either add a stove pipe adapter to it or replace the support box without having to replace the entire ~16 feet of Class-A chimney pipe above it?

I've consulted with both our local wood stove installer & our local chimney sweep, and they both say their insurance won't let them work on any part of the wood stove-chimney system with out replacing the entire Class A chimney due to the fact that no one knows when the chimney pipe was installed (the house was built in the late 1940's & we estimated the previous stove that was in there before the Avalon was likely installed not that long after (maybe 50's or 60's???) based on the set-up)

 

[begreen]

It probably should all be replaced, especially if that old. What did the installer and sweep say about the condition of the current chimney pipe? My guess is that it is underrated by today's class A requirements. The FB series today is rated at 1700º instead of their HS class A pipe with a requirement of 2100º. FB is not rated for solid-fuel appliances. You could give Amerivent tech support a call to verify.

 

[Mt Ski Bum]

they both said the condition of the chimney seems just fine. The way the pipe goes into the support box is the only issue either of them had with the set up (actually I take that back, the sweep said I should put a slip joint in somewhere on the stove pipe so it's easier to remove to vacuum out the soot after sweeping)

 

[Mt Ski Bum]

It probably should all be replaced, especially if that old. What did the installer and sweep say about the condition of the current chimney pipe? My guess is that it is underrated by today's class A requirements. The FB series today is rated at 1700º instead of their HS class A pipe with a requirement of 2100º. FB is not rated for solid-fuel appliances. You could give Amerivent tech support a call to verify.

just looked on their website where they describe a 10fb model as "engineered for venting all gas or liquid-fueled appliances and non-airtight solid-fueled fireplace stoves." The old stove was a non-airtight wood circulator, so I guess that explains why it was installed.. ironically, my Avalon until recently was also technically not air-tight (bought it used, had to replace gaskets & handle to get good door seal)

 

[begreen]

It's the 1700º rating that is the issue, UL 103. Keyword fireplace stoves, like an old Franklin with a lot of air mixed.

This chimney is listed (UL 103) for venting flue gases not exceeding 1000°F under continuous operating conditions. UL has also conducted tests at 1400°F for one hour and 1700°F for 10 minutes to verify compliance with UL test standards

You want UL 103TYPE HT for the wood stove. It's on page 10 of the Pendleton manual.

Use 6" diameter type UL 103 HT chimney from one manufacturer (do not mix brands) or code approved masonry chimney with a flue liner.