to cap or not to cap

[Henz]

That is the question. I had a new installation done last fall and it entailed a new SS chimney through the wall and up..There is a chimney cap on it. everything works good.
My neighbor had a new installation done and the outfit did not put a cap on it. his seems to draw better than mine just by looking at he amount of smoke going straight out...I thought you ahd to have a cap>?? But then again, I see with cement block chimneys many do not have caps

 

[Rhone]

Cap is required. Your neighbor's stove is gonna be swimming come summer when heavy rains go straight down his liner and creates a pool in his house or stove.

 

[Henz]

thats what I thought..thanks!

 

[Jags]

Also, if draft is an issue being caused by the cap, keep in mind that there are several styles of caps. The one I use can actually help to induce draft if the wind is blowing. Its important in my situation, with perfect wind conditions a "normal" cap would allow a backdraft into the stove on start up (until the pipe got warm). This would only happen if all conditions were perfect, but after the second time, I got a different cap. Hasn't happened in 5 years.

Edit: He needs a cap!

 

[Backwoods Savage]

Would you stand out in the rain without something on your head?

 

[DriftWood]

That is the question. I had a new installation done last fall and it entailed a new SS chimney through the wall and up..There is a chimney cap on it. everything works good.
My neighbor had a new installation done and the outfit did not put a cap on it. his seems to draw better than mine just by looking at he amount of smoke going straight out...I thought you ahd to have a cap>?? But then again, I see with cement block chimneys many do not have caps

http://i122.photobucket.com/albums/o242/towboatr/guardian806002-1.jpg

Another reason to not remove those chimney cap spark screens.

http://i122.photobucket.com/albums/o242/towboatr/topviewofboat.jpg

"I think ashes from our wood stove fell on top of the fir duff on the flat garage roof after a very dry sept ...

Served San Diego Navy Seals til GSA Auction Feb 06.
Restoration target: Provide rescue towing, crew boat and recreation on the lower Columbia River"

http://continuouswave.com/ubb/Forum1/HTML/013311.html

It was not my boat. It was a members boat on Continuouswave.com a Boston Whaler Information Forum site.

 

[budman]

Would you stand out in the rain without something on your head?

Thanks, I needed that.When i pulled my liner this summer to insulate it i
bought a new top plate and cap because i thought i would bend the heck out of the old one prying it off
of the chimney.Well the new one was from chimneyliner.com and when i started burning in Oct and
beginning of Nov that thing came off right away and put the magnaflex back on.That other one with the
wind guard filled up with curd so fast.

 

[Henz]

anyone have pics of their caps?? mine looks typical with a webbing of metal as the spark arrestor

 

[Metal]

Here are a few. The first one has a spark arrester, the second is just a plain rain cap. Spark arresters are required in some locations.

 

[Henz]

mine is a combination of the two

 

[webbie]

To add to the "learn something new each day" thing - I used to think that no cap was the best cap (draft-wise).

Reality is a stubborn thing - someone finally did some tests.

Hey, Metal, do you guys ever test or do you just assume because of rain, etc

https://www.hearth.com/econtent/index.php/wiki/Effect_of_wind_on_chimney_caps/

Thanks to Master John Gulland for the facts in this case...he had that study buried somewhere, and sent it to me years ago.

 

[Henz]

so in essence, no cap is the best overall

 

[Jags]

so in essence, no cap is the best overall

"To add to the “learn something new each day” thing - I used to think that no cap was the best cap (draft-wise)."

I think "used to" is indicating that he has changed his ways. ;-)

 

[webbie]

Exactly, I let facts get in the way of my opinion!

I think the situation could be described this way....

If the wind speed was always less than 5MPH, then perhaps no cap might be the best cap....

BUT

The winter wind speed is usually much higher than that, so that statement ends up being BS. The best cap is a cap.

The study also debunks the advantage of certain "wind helper" caps! But it does not account for the placebo effect. Once you spend $200 on a new draft increasing cap, it WILL help your draft.

 

[Henz]

someone show me a pic of a draft increasing cap???

 

[Jags]

Here is an example of one. I have no experience with it (can't find a pic of the one I use, it is VERY simple in comparison).

http://www.chimneysweeponline.com/vacustack.htm

 

[Henz]

ugly! but interesting..

 

[Jags]

Heres another if you want a mechanical one.
http://www.volko.com/Chimneyfan.htm

 

[Metal]

IMHO, wind over a chimney without a cap is like blowing across the top of a bottle. You are creating a "cap" of pressure and the sound you hear is the resonating pressure of the air inside. If you add a cap, you break up the wind or "pressure cap" blowing over the flue.

As far as testing goes, rain/wind tests are run and also draft tests are run with caps installed. Factory build systems are not usually tested without caps, so no data is available to compare. Caps are mainly installed to keep out debris/rain and keep in embers (when spark arresters are added) and in some cases like the Webmasters products, the also make the chimney look prettier.

 

[Cazimere]

After trial and error with a few round caps, I've found this style out-performs them all.

 

[Tendencies]

Beware of that cap on the left mentioned above (on page 1), several of us here have had problems with ash/creosote/gunk filling the holes and choking out the stove causing much smoke and ash to enter the house becasue of it. I removed every other divider and now it breathes no matter what while still providing rain protection.

T