# Chimney cap clogged!!



## sixman (Dec 24, 2010)

First year burning wood question for the panel. Is it normal to have to clean the wire mesh inside the cap due to it being clogged during the heating season or am I burning wrong?
Wood is dry, 3-4 years old and the black stuff was a crunchy dry texture. I ran a screwdriver around inside the mesh and tapped on the mesh to jar it loose and dumped it out.


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## mywaynow (Dec 24, 2010)

I am seeing a similar build up along with some dripping from the cap seam, down the pipe.  The cap is not blocked at all, but is getting a shinny black residue on the downwind side.  Only burned about 2 weeks now, 24/7.  Similarly concerned.


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## rdust (Dec 24, 2010)

It's not uncommon for caps with a fine screen to get plugged up.  I've heard of people taking the screens out or cutting the openings bigger.  

How does the pipe look?  If the inside is clear without any nasty build up I'd say you're burning fine.


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## branchburner (Dec 24, 2010)

Last year I had a gallon of black crunchy stuff on my cap/screen/chimney crown, and only a pint of fine brown powder in the entire 20'+ liner. I think it is pretty normal for creosote to condense on whatever it hits once it leaves the stack. Inside the stack is what you want to keep an eye on.


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## Wood Heat Stoves (Dec 24, 2010)

branchburner said:
			
		

> Last year I had a gallon of black crunchy stuff on my cap/screen/chimney crown, and only a pint of fine brown powder in the entire 20'+ liner. I think it is pretty normal for creosote to condense on whatever it hits once it leaves the stack. Inside the stack is what you want to keep an eye on.



yes, +1


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## tcassavaugh (Dec 24, 2010)

+2 I get it a the top on the cap. Sometimes pretty bad, sometimes not. Dependant on the moistuer of the wood and temperature i think. Also, if you burn at slower burns, i think it tends to accumulate because the gasses are cooler and can condense easier. I just crawl up on the roof about mid January and run a brush down the pipe (not bad normally) and knock the stuff off the cap.

cass


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## begreen (Dec 24, 2010)

We get several reports of this every year. Clogging is an indicator of too cool flue gas temps or in some case too much particulate, usually from burning a lot of paper or cardboard. Cool flue gases can be caused by running the stove too cool, wood that has higher moisture content and/or a long, cold, exterior flue. In the last case, there may be little you can do besides remove every other grid of the screen mesh to effectively double the size of the screen holes.

FWIW, I've had  stock cap screens on flues for the past 17 years and have never seen an issue with clogging. Both flues have been straight-up, interior up to class A, with about 7' exposed to outdoors.


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## lumbajac (Dec 24, 2010)

Can a chimney cap be unclogged by sweeping chimney from stove side up with flexible brush?

No way I'm going up on my pitch of roof with snow on it... 2 stories with 10/12 pitch.  Might have to I guess, but it's tricky enough with a dry roof.


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## Treacherous (Dec 24, 2010)

Early in season I burned wood too cool in my stove and got some clogging in my screen.  Nothing blocking things off but enough to make me concerned.  I was able to clean the screen remotely with a couple long paintbrush poles I picked up at Lowes.  I connected a small wire brush to the end of poles.  My roof is steep as well so this was a good compromise that allowed me to clean out the screen.  I just need to get someone up there to remove the screen next spring.  Too much ice and snow on the roof right now for any safe access.




			
				lumbajac said:
			
		

> Can a chimney cap be unclogged by sweeping chimney from stove side up with flexible brush?
> 
> No way I'm going up on my pitch of roof with snow on it... 2 stories with 10/12 pitch.  Might have to I guess, but it's tricky enough with a dry roof.


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## Renovation (Dec 24, 2010)

BeGreen said:
			
		

> FWIW, I've had  stock cap screens on flues for the past 17 years and have never seen an issue with clogging. Both flues have been straight-up, interior up to class A, with about 7' exposed to outdoors.



Good to know, thanks.


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## begreen (Dec 24, 2010)

lumbajac said:
			
		

> Can a chimney cap be unclogged by sweeping chimney from stove side up with flexible brush?
> 
> No way I'm going up on my pitch of roof with snow on it... 2 stories with 10/12 pitch.  Might have to I guess, but it's tricky enough with a dry roof.



It will help. Got an accurate pellet rifle?


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## sixman (Dec 24, 2010)

I know I am burning too cool but I can't help it. The rest of the chimney looked good. The guy that sold me the stove and pipe also sold me the spark arrester or screen that goes in the cap. Since I have a metal roof do you think it would be okay to remove the screen?


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## begreen (Dec 24, 2010)

I'd just open it up if need be. It won't take more than about 15 minutes with a pair of good diagonal cutters. Curious, why are you burning cool?


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## Mad Tom (Dec 24, 2010)

BeGreen said:
			
		

> lumbajac said:
> 
> 
> 
> ...



 A .22 works a little better. Just don't do it early in the morning dressed just in your boxers. The neighbors might be out walking their dog.


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## sixman (Dec 24, 2010)

Texas weather, gets too warm in the house.


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## begreen (Dec 24, 2010)

Yeah, you folks are on the cusp and getting fickle weather. It's 40F in Ft. Worth and 70F in Houston. Best thing to do is to burn smaller, hotter fires. Less wood = less heat. It will require more frequent feeding, but it will keep you off that slippery roof.


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## wkpoor (Dec 24, 2010)

First year I started burning/heating with wood I promptly chucked the spark arrester cap and installed a plain rain cap. My chimney is 35' and is only accessible by ladder. Can't take a chance when stove is my only heat. Wind tore off one rain cap a few years ago and I just went without totally the rest of the season. Don't really need a cap in the heating season.


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## Highbeam (Dec 24, 2010)

BeGreen said:
			
		

> We get several reports of this every year. Clogging is an indicator of too cool flue gas temps or in some case too much particulate, usually from burning a lot of paper or cardboard. .



I disagree. Clogging is only an indicator that you have a mesh filter on your chimney cap. While you are more likely to clog your cap with poor burning habits, the fact that your flue has clogged is not enough to conclude poor burning habits. Only the combination of the ideal stove, habits, wood, and chimney setup will allow you to run with a mesh cap and not experience pluggage more than once per year. 

My cap's screen would plug every few months until I removed it. The entire length of the chimney which is very similar to BG's would barely accumulate a couple of cups of creo over the whole 9 month burning season. It's mesh.


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## begreen (Dec 24, 2010)

Where did I say poor burning habits? Some flues run cool due to location and length. Sometimes it's the wood. And all caps are not created equal. What I did say is after 17 years of burning in this house  in two different flues, the mesh has never clogged. Next year for whatever reason, I might be burning damper wood and it could clog. The point is that it is possible to burn and not clog the screen.


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## joefrompa (Dec 24, 2010)

Just get your stove top reading 700-750, put a fresh load of wood on, then open up your flue all the way and your intake.

You want 1400 degree exhaust gases wooshing up that flue so hard that it blows your cap clear.

Joe

P.s. This post was 97% in jest.


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## kgrant (Dec 25, 2010)

My caps are easy to access and I burn 24/7 so durning the heating season I don't run caps.  Take them off and the fall and put them back on in the spring.


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## begreen (Dec 25, 2010)

It depends on your climate and region. I wouldn't advise someone living in tinder dry mountains like western CO to run without a screen. Nor for folks in urban areas. But in our wet Pac NW, or winter snowy Fairbanks, probably not a big deal.


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## Pagey (Dec 25, 2010)

joefrompa said:
			
		

> Just get your stove top reading 700-750, put a fresh load of wood on, then open up your flue all the way and your intake.
> 
> You want 1400 degree exhaust gases wooshing up that flue so hard that it blows your cap clear.
> 
> ...



3% is good enough for me, baby!  *Fires up stove and opens bypass damper*


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## Backwoods Savage (Dec 25, 2010)

I recall one time having the screen on the cap. We used to just stand on the ground and using a small light pole, would just tap the screen and the stuff would fall right off. Wear goggles!


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## sixman (Dec 25, 2010)

I am thinking that I could get away with taking it out of the cap. It did not come with the cap but installed at the recommendation of my salesman. I have a brick home with a metal roof so the only combustable near it would be the grass in the yard. Do you guys that don't have one see actual glowing embers leaving your stack headed for the ground?


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## wkpoor (Dec 26, 2010)

sixman said:
			
		

> I am thinking that I could get away with taking it out of the cap. It did not come with the cap but installed at the recommendation of my salesman. I have a brick home with a metal roof so the only combustable near it would be the grass in the yard. Do you guys that don't have one see actual glowing embers leaving your stack headed for the ground?


I would loose the cap but I live in Ohio. Its nothing but snow ice and mud here till long after the burning season is over.


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## sixman (Dec 26, 2010)

Actually winter time is our wildfire season. All the dry dead grass makes for a good tinderbox around here.


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## kgrant (Dec 26, 2010)

I've never seen embers fly out of my stacks here at home.  The only chimneys I've personally seem embers fly out of is an old homemade job that's at a cabin I go to.  Doesn't have any baffle plate or anything.  When burning hard it can shoot embers/sparks out of the chimney with a cap on it, and even if it had screens I don't think it would slow them down.  They all die within a few feet of the chimney.  I don't think a 5/8" mesh would stop these.

If you need it for code don't remove it.  If you have a lot of flammables around the house or whatever, keep it on and plan on cleaning the cap once in a while.  

The main reason I don't run a cap is because I hate the moisture that condenses on the cap and drips on my roof.

I forgot about my hot tub.  Think a spark arrester would help me?


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## Blue_Tractor_Man (Dec 26, 2010)

We have the same problem when burning sweetgum.  We stopped burning sweetgum and started burning oak.  So far no problem.  I used to have to climb up on the roof and tap the screen with my hand.  The little black crispies would fall right out.


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