chimney cap screen getting plugged. w/pics

  • Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.
Status
Not open for further replies.

Polarbear

Member
Sep 6, 2012
35
Some dirt road S/E MI
Pics first. Here is the cap. Pic taken with cell phone through binoculars.
Screenshot_2013-12-24-10-27-38.png 20131224_100729-1-1.jpg
 
Last edited by a moderator:
Here are the particulars of our setup...

The stove is a Hearthstone Phoenix. We installed it with all insulated pipe. I'm burning ash primarily. Wood was standing dead for years, CSS and burn in the last month. No major drying time, wood burns great no hissing or sweating. Moisture readings less than 20%.. most around 10% or less. Most wood is stacked in house 24hrs before burn. I'm getting very little ash at cleanouts. In the last 2 weeks one small 2 gallon bucket or less. This is our primary heat source so we burn 24/7. Late last winter or early spring I couldnt build a fire. A little investigating and a pair of binoculars and I could see the chimney cap was plugged. We blamed it on light burns we were doing heating in the 50 degree days. When we cleaned the chimney cap then we brushed the pipe and got about a cup of dust very little creosote. We started this season with a clean cap and pipe. I'm being told to remove the screen from the cap. Is that good advice? Also why am I getting so little ash? Thanks for your help. PB
 
I don't see removing the smaller screen as bad advice, I'd go to hardware store and buy something a little bigger to use as screen. I like to have a screen on the cap, I don't like birds in the fire box. Lol
 
  • Like
Reactions: Fred Wright
A few questions . . .

The moisture reading . . . is that on the face of a fresh split split? Some folks take a reading without freshly splitting the wood which is the correct way to get a more reliable or rather more useful reading. Just because wood is standing dead doesn't necessarily mean it's ready to go . . . but then again it doesn't necessarily mean it cannot be used either. No hissing is a good sign.

What temps are you running with the stove and flue?

Some folks have removed the screen and/or put in larger mesh.
 
Oh yeah pretty good picture, I like that
 
Stove temps on the stone run up to 500. The insulated stovepipe generally runs between 250 and 450. We usually reload the stove when the stovepipe reaches 200 degrees. Air open and close as needed. 20131215_192355.jpg
 
See comment in other thread. The wood is not fully seasoned to the core. Standing dead can still retain a lot of moisture. Moisture readings must be taken on a freshly exposed face of wood in a re-split.

Is the stove connected with single-wall pipe? If so, that is contributing to the problem by cooling down the flue gases a lot.
 
  • Like
Reactions: Fred Wright
All stovepipe including 45degree collar are insulated. So I see two different views on measuring moisture in the splits. I have measured both ways. Fresh split and split off the pile. We had alot of rain for a couple of days and high humidity. I'm sure that contributed to it. New neighbor is a chimney sweep/builder etc. I'll introduce myself and see what he has to say.
 
I also had the same problem at first, but time goes on and I am using 3 year css and staying that far ahead on wood, it has stopped and the cap stays clean.
 
  • Like
Reactions: Fred Wright
So I see two different views on measuring moisture in the splits

I think FirefighterJake forgot some punctuation in his reply. Both BeGreen & Jake are saying to measure moisture on the new face of a freshly split piece of wood.

Insulated pipe brings all the heat and moisture to the top of the pipe which is good. The problem is as it hits the cold screen all that moisture tries on condense capturing the particulate with it. This clogs the screen fairly quickly. A half inch wire mesh seems to work best as a top screen... The wire warms quickly and does not give much surface for the water to condense on...

KaptJaq
 
  • Like
Reactions: Fred Wright
Not the worst I ever seen, but I can almost guarantee you that wood ain't no where near dry enough.
Standing dead or not, just cut and split a month ago is damn near the equivalent of burning green wood.
If it is all you have, burn away, but keep an eye on the screen and clean as needed.
You can try bringing some wood in, if you want. It will dry fairly well in about a week or so, maybe not optimal, but much better then the state it is in right now.
A screen with larger openings ain't a bad thing either.
 
  • Like
Reactions: Fred Wright
I agree about the wood, so get rid of the screen. You don't need it in the winter, it's only there to keep birds out. Cover it back up in the spring when you are done burning.
 
well I'm hearing you guys say this is a rookie mistake and my wood is to wet. ugh! Funny thing is the MM is telling me otherwise and the burn no hissing foaming etc. I've burned alot of wood in my life and understand CSS is important. This is supposed to be the winter to get ahead on the wood. access to dead ash here in s/e mi is easy. I should be able to get it started for next year etc.

I guess I'll remove the screen for the winter and keep the stove hot. Maybe the way I let the stove cycle hot and warm is part of the problem. Off to church. Merry christmas! PB
 
Watch your codes where you live. Many municipalities requires screens as spark arrestors.
To just tell someone to remove the screen is just poor advice period.
It serves more purpose than just to keep birds out.
And with a decent sized opening screen and good burning practices, you won't have screen issues.
Most that say get rid of it are the ones who burn like crap, and constantly clog their screen and discard them in frustration, rather than better their wood &/or burning habits.
 
well I'm hearing you guys say this is a rookie mistake and my wood is to wet. ugh! Funny thing is the MM is telling me otherwise and the burn no hissing foaming etc. I've burned alot of wood in my life and understand CSS is important. This is supposed to be the winter to get ahead on the wood. access to dead ash here in s/e mi is easy. I should be able to get it started for next year etc.

I guess I'll remove the screen for the winter and keep the stove hot. Maybe the way I let the stove cycle hot and warm is part of the problem. Off to church. Merry christmas! PB
For sure that can be.
Every time you fire a stove the pipes are cool and you send a lot of gas's at light off up the flue that the secondary combustion doesn't get a chance at.
Good thought you had! Cheers!
 
There are other types of caps that keep the birds out but do not rely on the mesh for that purpose. Those are generally a better choice but of course cost a bit more. The one I am using is from Selkirk no mesh, nowhere inside it for a feathered friend to perch or on the out side to be able to hop inside.
 
From the pics it looks like the screen has a pretty small mesh size and a thick wire.
I have a Simson cap ( now Dura Tec), it has a about 1/2" mesh with a fine stainless steel wire.
You can see it here:

http://www.northlineexpress.com/chi...-pipe-1/6-duratech-chimney-cap-9484-9484.html

It might be worth replacing your existing screen with a Dura Tec screen, ( you can buy just the screen).

BTW I just cleaned my chimney yesterday and there was no buildup on the screen at all.:cool:
 
Yea I would install a new screen or cap with larger openings. Subjectively that screen seems restrictive. On another note though that is some pretty good buildup...and would be suspect of your wood being a primary concern.

It sounds like you have a moisture reader? I would split one of your stacked pieces and get a reading from the inside if you aren't already doing so.

I would get up there and double check the chimney as well if you can do that easily and safely.
 
"Creosote is black or brown in appearance. It can be crusty and flaky…tar-like, drippy and sticky…or shiny and hardened. Often, all forms will occur in one chimney system. Whatever form it takes, creosote is highly combustible. If it builds up in sufficient quantities – and the internal flue temperature is high enough – the result could be a chimney fire. Certain conditions encourage the buildup of creosote. Restricted air supply, unseasoned wood and, cooler than normal chimney temperatures are all factors that can accelerate the buildup of creosote on chimney flue walls. Air supply may be restricted by closing the glass doors, by failing to open the damper wide enough, and the lack of sufficient make-up air to move heated smoke up the chimney rapidly (the longer the smoke’s “residence time” in the flue, the more likely is it that creosote will form). A wood stove’s air supply can be limited by closing down the stove damper or air inlets too soon or too much. Burning unseasoned wood – because so much energy is used initially just to drive off the water trapped in the cells of the logs– keeps the resulting smoke cooler, than if seasoned wood is used. In the case of wood stoves, overloading the firebox with wood in an attempt to get a longer burn time also contributes to creosote buildup - See more at: http://www.csia.org/homeowner-resources/the_facts_about_chimney_fires.aspx#sthash.wLkFu7bV.dpuf"
 
  • Like
Reactions: CenterTree
Watch your codes where you live. Many municipalities requires screens as spark arrestors.
To just tell someone to remove the screen is just poor advice period.
It serves more purpose than just to keep birds out.
And with a decent sized opening screen and good burning practices, you won't have screen issues.
Most that say get rid of it are the ones who burn like crap, and constantly clog their screen and discard them in frustration, rather than better their wood &/or burning habits.

A "decent sized opening" completely negates the spark arresting feature....because a "spark" can travel right through it. I agree with you on one point, I do burn marginal moisture content wood because I can, and PolarBear has already established he has marginal wood this season, so I think taking the screen out is a viable option at this point and time. I run a WindBeater cap and it has no screen and was not designed not to have one, sorry but I love the thing:
http://www.amazon.com/HomeSaver-14908-Stainless-Windbeater-Chimney/dp/B002VFHW12
 
"Creosote is black or brown in appearance. It can be crusty and flaky…tar-like, drippy and sticky…or shiny and hardened. Often, all forms will occur in one chimney system. Whatever form it takes, creosote is highly combustible. If it builds up in sufficient quantities – and the internal flue temperature is high enough – the result could be a chimney fire. Certain conditions encourage the buildup of creosote. Restricted air supply, unseasoned wood and, cooler than normal chimney temperatures are all factors that can accelerate the buildup of creosote on chimney flue walls. Air supply may be restricted by closing the glass doors, by failing to open the damper wide enough, and the lack of sufficient make-up air to move heated smoke up the chimney rapidly (the longer the smoke’s “residence time” in the flue, the more likely is it that creosote will form). A wood stove’s air supply can be limited by closing down the stove damper or air inlets too soon or too much. Burning unseasoned wood – because so much energy is used initially just to drive off the water trapped in the cells of the logs– keeps the resulting smoke cooler, than if seasoned wood is used. In the case of wood stoves, overloading the firebox with wood in an attempt to get a longer burn time also contributes to creosote buildup - See more at: http://www.csia.org/homeowner-resources/the_facts_about_chimney_fires.aspx#sthash.wLkFu7bV.dpuf"
I often load my insert up full, up to the bottom of the baffle, and the only time I had any problems with creosote was the first year, not due to "overloading" the stove, but due to wood that was not as dry as it should have been. And only had to clean it once mid season. Good wood since, and never had the screen anywhere near clogged. Even during extended burning seasons say Oct to April. So the "CSIA" theory may apply to some(prolly poor wood), but absolutely not all.
 
A "decent sized opening" completely negates the spark arresting feature....because a "spark" can travel right through it. I agree with you on one point, I do burn marginal moisture content wood because I can, and PolarBear has already established he has marginal wood this season, so I think taking the screen out is a viable option at this point and time. I run a WindBeater cap and it has no screen and was not designed not to have one, sorry but I love the thing:
http://www.amazon.com/HomeSaver-14908-Stainless-Windbeater-Chimney/dp/B002VFHW12
To each their own, whatever works for you is great.
While a screen won't stop smaller embers etc., it will catch paper ash etc, that many use to start their fire. This is probably why some municipalities require a screen. More often in dry, wooded areas.
The screen debate has been debated enough times, so anyone wanting to read all that can search it up. Removing the screen for some, should be a last resort, but is also a bandaid to another issue. Unless of course, the cap, like yours, is not intended to have a screen.
 
Yeah, I don't' want to banter the screen thing too much, but remember 99% of masonry fireplaces have no screen and PolarBear has a steel roof so there is zero chance he is going to set his roof on fire.
And this is an honest question with no sarcasm or derision intended, but can you honestly say you have never ever had to clean your cap screen since burning "good wood"? Because if your answer is no, then I'll admit that I have been doing something horribly wrong for many years.

One more thing, and this is just my opinion. I think screens give many the warm and fuzzys on safety, but they cause more dangerous problems with those who burn marginal wood. They are a designed choke point by not allowing those un-burnt particles to escape the flue which & once severely restricted accelerate the accumulation of flue creosote. All of us should be burning good wood, but it just does not always happen.
 
Last edited:
Whoops, sorry I confused this thread with the other one down below, I do not know if PB has a steel roof or not....
 
Status
Not open for further replies.