*** The CHIMNEY CAP thread ****

[Roospike]

With seeing and reading the different threads and posts on chimney caps getting clogged with krap i feel we need to look into some of the issues.

Wile we have some say keep the cap on the chimney and some say to take it off how about we look into the issues of caps and the design.

I am on the side to say on the forum to keep the cap on the pipe BECAUSE i do no want birds and such in the pipe and i also feel that it helps keep out rain and snow from going down the pipe. I also state on this forum to leave the cap on BECAUSE there are so many people burning junk like paper and cardboard in there stove and i feel the chimney cap is going to help keep the burning fly ash in the pipe. Its hard to just say "yeah , just take the cap off" when you know there are people burning paper and such in there stove.

From what i have read on the forums its looks to "me" that the issues of the krap in the chimney cap are on the side of stoves with liners and not so much with double wall stainless steel class A chimney pipe .............but thats what this thread is about. With all the stuff we talk about here one would think we could get to the bottom of the clogged chimney cap issue.

I'll start , If my feeling is true that the issue is mostly chimneys with liners and as i notice the liner sticks out past the chimney 6"-12" i would think is really going to cool off the pipe and collect krap in the top of the pipe and the cap. What if one could take a short section of double wall class A stainless steel 8" pipe to place on top of the chimney were the liner comes out and run the hook togother class A cap pipe to it ? this would hep insulate the top section of the exposed liner to the wind and cold.

Information on different screen sizes , different cap styles ect... all information is welcome. This sounds like and easy fix but i dont feel we have put out thumb on the issue to change the problem.

What-ch got boys and girls? pipes , caps , screens and sizes , insulated or non insulated .....

web link of different class A pipes that could be installed on top of the chimney. Comes in lenghts of 6" , 12" , 1 ,24" , 36" , 48" in sizes of 6" ,7", 8' , 12"

(broken link removed)

 

[Roospike]

pic#2

 

[Roospike]

Pictures of my class A stainless steel pipe and cap.

pic 1 is normal burning.
pic 2 is closer pic of the cap and was after a snow storm.

If anyone has pic please post your set up.

 

[Roospike]

FIXED IT__Swept from the bottom…..still won’t burn. pics included thread..
https://www.hearth.com/talk/threads/6949/

 

[Hogwildz]

I have double wall rigid insulated from first tile flue to top. It does stick out about 1-1/2', The cap gets the worst buildup, then of course the 1-1/2' of double wall sticking out the top does get some, but not like the cap. I feel no matter what you use, the pipe that sticks out the top of the top plate is going to be cooled no matter what you do, or what you use. Mine doesn't get all that bad. The cap, well thats just something I deal with. I too don't want anything coming down the pipe, only smoke going up & the spark arrestor function. I live in the woods and don't want the woods going poof, and I am sure what few neighbors I have appreciate that.

 

[Eric Johnson]

I have a chimney cap, Roo, and I'm not happy about it.

I used to run bare, but then I put on an add-on cat and had to have a cap to protect it from thermal shock. I've since taken out the cat but haven't been able to get back up onto the roof to remove the cap. Yes, I have a Duratech chimney from the boiler to the cap. It still kraps up from time to time. I removed the screen before I installed the cap.

I'm hoping that my new boiler, which will be a gasifier, won't generate enough creosote to affect the cap, so I'm keeping it on there for the time being.

But if it gives me any more crap----off it goes!

 

[Metal]

You can get caps without spark arresters if they are allowed in your jurisdictions. Attached are the two types from Metal-Fab.

 

[TMonter]

I seem to get buildup on the cap and the first 6-10" of stainless liner myself. After that the chimney is clean all the way down to the stove. Mine got so bad I cut out two large chunks of the screen to alleviate the problem and that has seemed to help.

Really the cap is only there for keeping critters out and to keep a downpour from coming down the chimney.

 

[Roospike]

I have one of the caps Metal posted pic of and dont have a problem with it. As you can see in my pics it will get brown but it never gets clogged up.

So with that said, its it the cap design ? is it the style of chimney? how much difference does the stove make per how the cap turns out ? Does a liner running thorough a brick chimney make a lot of difference ?

With all the different installs we have i thought maybe we could figure out what changes make to the the outcome of a clean chimney cap to a clogged one.

If were are getting clogged chimney caps then as we can see in other post that is going to make a world of difference on how our stove will run and draft. With all the talk of .2 grams per hour of emissions from one stove to the othere i feel a chimney cap getting clogged is going to make a bigger difference. Its also an issue that most of us can't just go up on the roof to change/clean when ever we want so finding the best performance for draft i would think should be key. With a clogged chimney cap i guess it doesn't matter what stove you have the performance is going to drop and cat vs non cat or grams per hour per stove is a moot point.

 

[Gunner]

I think it is the cap design...driving around I see alot of really constrictive caps almost like they are to be used with gas appliances not wood. You know it's wood tho by the black chit all over it.

 

[BrotherBart]

DavidV's clogged cap was caused by a long day of smoldering soaking wet wood as detailed in his earlier post. Probably any cap would crap up when that happens.

Mine has large holes in it and no screen and the buildup I have found was on the underside of the top and on the top of the flat surface on the bottom. That sheet stainless standing up there in the cold wind is gonna collect creosote no matter what is done. No problem with the holes clogging though.

Hell, after thirty years of scrapping glaze creosote out of chimneys a little sote on a cap, now that the flues are lined, is not a problem. Just smack it against the chimney when I go up to brush the pipe.

 

[Sandor]

I have one of the caps Metal posted pic of and dont have a problem with it. As you can see in my pics it will get brown but it never gets clogged up.

So with that said, its it the cap design ? is it the style of chimney? how much difference does the stove make per how the cap turns out ? Does a liner running thorough a brick chimney make a lot of difference ?

With all the different installs we have i thought maybe we could figure out what changes make to the the outcome of a clean chimney cap to a clogged one.

If were are getting clogged chimney caps then as we can see in other post that is going to make a world of difference on how our stove will run and draft. With all the talk of .2 grams per hour of emissions from one stove to the othere i feel a chimney cap getting clogged is going to make a bigger difference. Its also an issue that most of us can't just go up on the roof to change/clean when ever we want so finding the best performance for draft i would think should be key. With a clogged chimney cap i guess it doesn't matter what stove you have the performance is going to drop and cat vs non cat or grams per hour per stove is a moot point.

Both of those caps look good. The cap I had a problem with had a bunch of louvers that were facing down to deflect rain, with not much open area. As someone said, it looked like it belonged on a gas furnace. I guess when that Regency was attempting to burn at something less than WOT, the smoke just lingered, and glued up.

I would not think that either cap pictured would ever have a problem. The cap I currently use looks like the bottom pic. No probs.

I have only used Class A.

 

[BrotherBart]

The seven dollar galvanized jobies at ACE Hardware look like the last one and I am thinking about giving a couple of them a try.

If it gets hot enough up there to require stainless to survive then I have a much larger problem taking place 25' below. Let it blow the cap into the woods.

 

[elkimmeg]

BB about a month back we discussed this issue the cap is not part of the liner listing, therfore unless your county requires a spark arrestor, a common rain cap will do.
I there is no language I have read or code that says x brand is the only option. Or that screen can be removed or can not be removed only if spark asseston is required. There is no listing on the cap Ul 1777 is liner exclusive for clearances to combustiables the cap sits above all combustiables and clearance requirements however elements shielding is code required.

 

[begreen]

Methinks, Bart likes to keep a cheap loose cap on his stack for taking potshots at his neighbors.

 

[DavidV]

Methinks, Bart likes to keep a cheap loose cap on his stack for taking potshots at his neighbors.

I wonder if you could modify a tater gun to shoot chimney caps. .....Dang and here I am with neighbors I like.

 

[DriftWood]

I have used a Metalbestos System. It had a optional screen on the cap which I took off as it loaded up to much. It was 1986 system and pre EPA air tight Sierra wood stove venting thorough the roof two feet from the peak of a ranch style home.

The Hearthstone Heritage Woodstove I have now is vented to a insulated,100% 316 Ti Homesaver UltraPro Chimney liner in a 1944 masonry fireplace that has a steel firebox and north facing exterior three flue chimney. The screen on the (broken link removed to http://www.hartshearth.com/ProductCart/pc/viewPrd.asp?idcategory=0&idproduct=3437) had no load up all winter.

 

[Gooserider]

It would seem to me like a question of cap design - how big are the holes vs. the size of the mesh or other gratings? What is the overall ratio of square inches of cap opening to the area of the opening? Lots of the caps I've seen photos of look like the amount of open area is less than the area of the pipe, so are they already constricting the flow before any crud even gets a chance to build up?

My cap is a square box over a double flue chimney, with a screen made of light guage expanded stainless, looks like about 1/2" square openings with the wires being about 1/8" wide. I can see LOTS of crud built up on the underside of the cap plate, and a fair bit on the grid, but never enough to block many of the openings (and remember this is with a pre-EPA smoker) I often see little flakes of creosote on the front walk around the bottom of the chimney, so I'm assuming that either the wind shakes the crap off occasionally, or my periodic hot fires are burning / blowing it off - I'm not going up to clean it, as I basically can't reach my chimney top...

I'm sure that cooling the pipe helps contribute to the clog, but I think the cap design is a bigger factor - I'd say to look for a cap with as much open area underneath for the smoke to get out as you can. Even if spark arrester caps are required, my understanding is that just means a limit on the size of the individual holes, not that you couldn't have a cap with LOTS of screened area on it.

At worst, it would seem to me like having more exit area would mean that the cap takes longer to get clogged - I can't see how it would make things worse.

Finally, as a "partly baked idea" department thought - would there be any reasonable way to put a heating wire in the cap to let a person plug it in and burn the crap off it periodically?

Gooserider

 

[Metal]

BB about a month back we discussed this issue the cap is not part of the liner listing, therfore unless your county requires a spark arrestor, a common rain cap will do.
I there is no language I have read or code that says x brand is the only option. Or that screen can be removed or can not be removed only if spark asseston is required. There is no listing on the cap Ul 1777 is liner exclusive for clearances to combustiables the cap sits above all combustiables and clearance requirements however elements shielding is code required.

UL 1777 part 7 states:
Exception: A cap is not required to be provided, when a cap is commercially available that:
a) Has been found to comply with the Rain Test, Section 30, and with the requirements for the material from which the cap is formed, and
b) The use of such cap is specified in the installation instructions of training manual.

UL1777 part 30 is the rain test, which caps must also pass.

Therefore, X brand is the only option, unless the installation instructions or training manual specify others that have been tested with the rain test.

 

[Harley]

Finally, as a "partly baked idea" department thought - would there be any reasonable way to put a heating wire in the cap to let a person plug it in and burn the crap off it periodically?

HHHHMMMMM - One thought comes to mind..... (sorry Babs... had to "steal" your pic. :lol:

 

[elkimmeg]

liner company BDM listing says only needs a rain cap did not list any brand to comply
How does this effect extenda flue wind beater or Vacu- stacks caps? Can they be substituted or does that make them non compliant to UL 1777?

According to Copperfields UL listed Home saver Pro Guardian cap are Ul listed for use with all homesaver flex re lining and it works great with Heat Fab although not Ul listyed
for Heat-Fab. As an inspector I wondering if I have not paid enough attention to chimney caps and their listings? Should I fail all thoses that substituted the listed cap for Vacu-stacks?

I guess I need to check the termination caps ,but I am not required to carry around a 40 extention ladder. I can request a staired pipe staging with safety guards to be erected so that I can confirm the cap. I don't think that will happen because the stagging cost will be more than the cap and installation. I do have language that safe access shall be provided for inspections

 

[Metal]

I am not saying you can't/shouldn't, but wanted to make sure you knew that it was in the standard and that they are tested as a system. The test is for keeping things out (debris and rain) and making cleaning easier (removal with common tools) and has nothing to do with clearances. I would have brought it up a month ago in the other thread (I thought I did) but it must have gotten buried too quickly for me to see it.

 

[elkimmeg]

since insulation is needed to comply with 1777 and 1777 compliance is only needed in chimneys that are not NFPA 211 compliant I woould say that I'm pretty safe not worring about chimney linse caps in chimneys where I did throat inspections over the past 10 years I only have to be concerned with older s unlined of ones in diss-repair so that eliminates the need to be concerned
as far as correct liner caps If one does not need the UL 1777 to bring their chimney into compliance and is only using the liner to comply to cross-sectional codes ,than the cap applied only has to be a rain cap.. Naturally Class A chimneys are of system wide UL acceptance including the cap, unless listed for substitution or the substituting cap is listed.

 

[Dunadan]

I need to replace the current multi-flue cap I have on my chimney, and I'm planning to replace it with 3 separate caps. I have a question though.

I see the (broken link removed to http://www.hartshearth.com/ProductCart/pc/viewPrd.asp?idcategory=0&idproduct=3437) mentioned in this thread, and many similar to it online, but the screen height is only 5". I was under the impression there should be at least 6" between the top of my liner and the cap. Is it that this 1" doesn't really make a difference, or is there another explanation?

I did go online and see The Forever Round Cap. It has an 8" high screen, and is half the cost of the Home Saver above. It seems to me, especially based on clearance from end of liner, this would be a better way to go.

Thoughts?

Also, if I have a 6" flex SS liner, should I assume that any cap that designed to fit a 6" diameter liner, or that calls itself a 6" cap will work for me? Sorry if this is a dumb question, but I'm thinking how with wood a 2x4 does not really measure 2" x 4".

Thanks,

Sean

 

[elkimmeg]

I would certantly have separation distance above flues making it less of a down draft pulling down smoke from the stove exit into an adjacent flue

thanks for bringing up this post it ties in with the ZC liner post discussion