Help!😩Smoke Billows in Room! NEW Majestic Biltmore 42”

[begreen]

The ovaling on the cap rim is not warping. It's just the flexing of the thin metal rim. The rim will conform to the roundness of the chimney pipe when attached. I came to the conclusion of negative pressure a while back and still think the restrictive cap design is not helping. This seems to have been proven by the test with it off.
Whether adding 4' of chimney pipe will overcome the negative pressure or not is to be determined. With 4 ft added the chimney will need 2 braces. one at 5' and one at 10'. If the chimney pipe is chased, then the bracing will be different. There it gets braced with the proper braces to the interior of the chase.

 

[Trevor Tahclep]

Now I understand why these products are not sold here in the province of Quebec.
I absolutely do not like that cap as it seems overly restrictive and needlessly complex to me.

 

[stoveliker]

I agree with the second part of the latest Majestic communication.

The first is then covering their behinds. There is nothing more fancy going on in chimney caps other than their impedance to air flow (unless you have one designed for high winds).
No venturi effects etc. Just "can the gas get out". It's a turbulent and/or diffusive flow (not laminar) and with varying wind and exhaust flows, that turbulence will be - turbulent. I.e. not consistent.
If one little bend is going to affect the efficacy of that cap, it's designed too close to the boundary of functioning. The safety margin is then too low and the cap sucks - and should be replaced by a newer one (without a larger range of operation, and thus less chance of exhaust going into the room - which is a safety issue too!).

 

[No More Smoke-Shows:(]

Guess what!?? 😳

The installer came out today. We popped the old cap, and just rested the additional 4' section with a new cap on top.

We had the windows sealed up and were 98% good. A bit of smoke on a couple occasions (especially when we moved around the wood and ash). But for the most part burned a 35 minute fire with the windows closed for 95% of the time.

So I think the plan should be to build up the chase so we can extend the chimney. Also, I'm wondering since the 4' made such a huge improvement, when we go to extend the chimney for good, if we shouldn't just add the additiaon 18" piece he had for good measure? In hopes that helps the tiny bit of smoking that we still saw?

BTW - all of your help has been a REAL blessing in getting to this point! So thank you, THANK YOU! 🙏🏻😁

 

[Wisco Shepherd]

I've been keeping up with this thread and I remember early on this was suggested. I know lots of other things had been suggested but this is probably a good example for folks that when you hear hoofbeats it's probably safer to assume it's a horse than a zebra.

 

[GG Woody]

Pics of the new cap?

 

[No More Smoke-Shows:(]

Pics of the new cap?

GG Woody, the new cap is exactly the same manufacturer's cap- just new and not dinged up.