Is top of chimney & cap reliable creosote indicator?

[mar13]

Can one use the chimney cap, cap screen, and top few inches of the chimney as a good indicator of whether or not to a chimney needs cleaning?

I've never cleaned my chimney since getting a new PE Alderea T5. (Previous non EPA stove could go quite a few years between cleaning with my wood volume and burning style.) About 2.5 cords so far, straight shot double walled pipe, very dry wood and I try to keep the burns smokeless. Anyhow, I never did break out the still-in-the box sooteater this summer, but I was on the roof today cleaning gutters and I was able to crawl up to the chimney and inspect the cap and first few inches inside the chimney. Very clean. (The cap doesn't seem immediatley easy to take off to inspect further down, especially on a steep roof.)

I'm feeling too busy this fall to learn the use of the sooteater and messing with dropping the stove's baffle, so I'd like to push off cleaning until later in the season.

 

[VintageGal]

Good question.

 

[mpaul]

How many years since your last cleaning?

Seems risky.

Cleaning a chimney is part of home maintenance, Sure you might be able to get away with not doing it, but sooner or later you’re going to get burned.

I started using the sooteater last year. Very easy to use and gives me piece of mind knowing my chimney is clean as I enter this years burning season.

 

[Simonkenton]

Bad test. There is much more crud in the lower part of the pipe than there is at the top.

 

[Ashful]

Bad test. There is much more crud in the lower part of the pipe than there is at the top.

Not in my chimney. I would say 90% of everything I get out is from one of two locations, with almost nothing in-between:

1. Connector pipe
2. Top 2 feet of chimney

An insulated pipe is usually going to see the most accumulation at the top, as that's most exposed to the cold. Creosote deposit is maximized when the water vapor to which it clings condenses in a cool pipe. Keep the air warm on the way up, and you minimize deposition. This is the whole basis of the "too cool" vs "burn range" on the ubiquitous FlueGard thermometers.

I'm not suggesting anyone skip cleaning based on inspection of only the top two feet, that's just careless and lazy. But in order to find a clean top on an otherwise dirty pipe, you'd have to cool the flue gasses so dramatically on the way up, that I'd think you'd have trouble maintaining any draft at all. I'm sure there's an exception somewhere in the world, but it wouldn't be typical to find a dirty pipe with a clean top.

 

[stoveliker]

I guess that also depends on how long your connector pipe is.

My double wall connector pipe and the T into che chimney sees most soot, and my cap is mostly clean.

Bottom line, this depends too much on the variables of your system, and you'll only know after you've seen a few years how it behaves. Hence, it's best to sweep often at first, and to decrease the frequency only once you learn how it behaves. (Or not decrease at all..)

 

[EbS-P]

Generally I would say just looking at the top it’s not good enough. BUT you are obviously burning dry wood cleanly if your previous stove went a few years between cleanings. All my build up it’s in the top few feet below that is just ash.


I say it’s probably time to verify how clean the new stove is burning. Then set your sweeping schedule based is what you observe.

 

[Mutineer]

I agree with EbS-P, buckle down and clean it now then give us, and yourself, a report on how much schmutz you pull out. Good real world test and data point that we all might learn from.

 

[Simonkenton]

"Not in my chimney. I would say 90% of everything I get out is from one of two locations, with almost nothing in-between:

1. Connector pipe
2. Top 2 feet of chimney"

That is interesting, Ashful. When I sweep my pipe, 90 percent of the crud is in the first ten feet of pipe, going up from the stove. Same deal with my brother's pipe. We could just sweep the first ten feet and call it a day. Of course we do sweep the entire pipe.

 

[stoveliker]

Ashful, which chimney is that (top 2 ft)?
You ahve a short one and a tall one, right? Or does that hold for both?

 

[bholler]

It varies allot. In most cases there will be more buildup at the top. But that absolutely is not always true

 

[Ashful]

Well, bholler spoke, and I'd be willing to bet anyone a beer that he sweeps more chimneys every week than any of the rest of us see in three years. There's just no arguing theory against experience.

But to answer stoveliker's question, I notice the "2-zone" phenomenon in the taller pipe, as I easily have 20 - 25 feet of clean pipe in between these two dirty zones, which makes it very obvious. The same thing happens in my shorter pipe, but it's just to such a smaller degree that I'd probably have not ever noticed it, without first seeing a much more obvious example in the taller pipe.

 

[Eman85]

You've got the sooteater already. I'd clean it but that's just me and I've had a chimney fire years ago. It's exciting, much more exciting than cleaning the chimney which is pretty boring and dirty.

 

[highanddryinco]

...have 20 - 25 feet of clean pipe in between these two dirty zones...

Nearly identical here. Almost zilch up to about 18', then about 2' of crap. Then clean again for another 8-10' until I near the cap and get a little more. Might be all those pine chimney fires keeping me clean.

 

[rwh63]

Not in my chimney. I would say 90% of everything I get out is from one of two locations, with almost nothing in-between:

1. Connector pipe
2. Top 2 feet of chimney

An insulated pipe is usually going to see the most accumulation at the top, as that's most exposed to the cold. Creosote deposit is maximized when the water vapor to which it clings condenses in a cool pipe. Keep the air warm on the way up, and you minimize deposition. This is the whole basis of the "too cool" vs "burn range" on the ubiquitous FlueGard thermometers.

I'm not suggesting anyone skip cleaning based on inspection of only the top two feet, that's just careless and lazy. But in order to find a clean top on an otherwise dirty pipe, you'd have to cool the flue gasses so dramatically on the way up, that I'd think you'd have trouble maintaining any draft at all. I'm sure there's an exception somewhere in the world, but it wouldn't be typical to find a dirty pipe with a clean top.

my experience as well. uninsulated single wall ss flex/rigid liner in inside chimney. most all soot collects on the upper most liner section. sweeping results in very little total fine dust.

 

[mar13]

Thanks for all your feedback. Like many of you stated, I'll find out - for my own particular case - once I use the SootEater come either Thanksgiving or Christmas break. I'll give an update once that happens.

(I'm assuming that falling ash/creosote relative to how far the SootEater has been inserted will let me know where the bulk of the creosote collected.)

 

[stoveliker]

Yes, unless you have draft that blows the ash out the top.

But ash and very fine stuff is the least problematic imo.

 

[Isaac Carlson]

We get buildup in the single wall where it goes into the masonry chimney, but only when burning on low or with wet wood. It gets bigger there. The rest of the chimney is pretty clean. Dry wood reduces it a lot.