How clean is your chimney cap?

[JotulOslo]

Hi,
We have been running our Jotul Oslo F500 for a month or so now and I have a question about the amount of build up I am seeing on the underside of the stainless steel chimney cap I installed as part of the flexible liner. I am not certain if this is or is not normal, so I have included two pictures I took today from the ground. In order to do this I used a Meade telescope with a 45 degree prism, and pointed the digital camera into the eyepiece. Hence the vignetting around the edges. I am thinking that I should get up and look down the pipe to properly determine what is going on.

None of the wood we burn has been wet, in fact it has been drying for a year and protected from the rain and snow. We tend to run the stove with the stovetop temperature from 500-600 degrees, and before we go to bed we adjust the air control way to the left to ensure an overnight burn. A few pieces of pine are burned here and there, but again, at the 500 to 600 degree range.

Any thoughts?

JotulOslo

 

[Eric Johnson]

Despite what you may have been led to believe, creosote happens, even with ultra-efficient, clean-burning modern stoves.

My word for chimney cap is "creosote catcher." I never used one before getting an add-on catalytic combuster, but now I need the cap to protect the cat.

What I did do was to take out the spark arrestor screen, which helps. If you can get a brush up there from inside, then you can probably knock most of it back down into the pipe or onto the roof. If not, then you might need to climb up there at some point (but not for awhile, judging from your pic). and knock it loose. Despite its appearance, it's not stuck to the metal very well.

More likely, when you start running some hot fires, it will vaporize and/or drip back down into the chimney and you won't have a problem. If you're not burning your stove hot now, then start.

 

[JotulOslo]

Master of Fire!
Thanks for the advice. I will probably go up there next weekend to perform a close inspection and run a brush down from the top. I have the fiberglas rods at my father's house, and will buy a suitable brush for the SS pipe. If I remember correctly the holes in the spark arrestor were pretty big. I may not have trimmed the excess pipe as close to the internal clamp as I should. When I go up there I'll bring a Dremel with a cutoff wheel, or maybe an air powered cut off tool, and knock it back some.

Thanks again, this is a wonderful resource!

Best regards,

JotulOslo

 

[Eric Johnson]

Hey, no problem, firestarter.

Anyway, get a poly (pastic) brush for cleaning that chimney, and make sure it's cool before you stick the brush in there, or you're going to melt the bristles.

And what I said ain't the final word. I hope somebody else will chime in with some tips on keeping the creosote from building up. Hotter fires is my only suggestion.

I also expect somebody to object to the practice of removing the spark arrestor, so I'm looking forward to debating that.

Anyway, good luck Jotul--and be careful up on that roof.

 

[wg_bent]

That seems like a quite a bit of build up, but looks kinda like fly ash...kinda hard to tell. I agree with Eric that if you burn hot, you won't have much problems.

 

[Sandor]

Yea, I'll chime in. I will never have another chimney cap with that mesh in there.

Up in WV, I had one, and it would glue up. Looking below the cap, the pipe was not bad. The only thing I could figure was that -10 degree wind would cool the screen off, and creosote would form. The stove burned really clean maybe 90 percent of the time, but I guess the other 10 percent did it in.

 

[Eric Johnson]

The Masters of Fire Have Spoken!

 

[Hogwildz]

Just bought this place a few months ago, and sad to say I don't have a cap yet. I am going to be relining & installing new insert, so I really don't want to waste the money on a cap that will be used for a short period of time. Luckily, not much rain gets in, and haven't had any downdraft problems. Crosses fingers.

 

[Mike Wilson]

Think of it this way... its a cold chimney cap, out there in the wind, acting as a condensing unit for your smoke... instant creosote. Yeah, hot burning will reduce it, but not eliminate it.


-- Mike

 

[BrotherBart]

Yeah. The underside of the top of both my caps glazed over in nothing flat with no accumulation in the the pipes just under them. I guess I bring'em down in the off season and take the propane torch and light'em off for a little cap cleaning.

 

[spot]

O.k. I'm probably a doofus for doing this, but...
I actually added extra sparkscreen to my cap.

Here's the story: I get some splits going and I take the dog out for a tinkle. As I wait for her to choose the perfect spot to pee, a nice big red ember floats down in front of me and lands in a pile of dry fall leaves. It sits there not showing any signs of dying soon, so I stomp it out and go to the side of the house to check the chimney (and cap). Sure enough, more embers float out. Some go out right away, but some stay red and float a long time!

I live smack dab in the middle of town with neighbors only a few steps away on either side. All the trees are dry. All the leaves on the ground are dry. And I'm shooting sparks!

I went in and doused the fire. The next day I took the chimney cap off and added an extra layer of spark arrestor screening to it. The original screen is galvanized mesh with 1/2 inch squares. According to my research 1/2 inch is as small as you want to go with screen size. (5/8 is standard) So I bought more of that and put it on a few inches away from the original mesh. It can be easily removed if I have to.

Please tell me if this is a totally stupid thing to do. I just want to prevent sparks and embers from leaving the cap. I don't want to "choke" the chimney or cause draft problems. However - I would rather clean my creosote catcher several times a year than burn my neighborhood down.
I am burning tonight and the embers seem to be a lot fewer, smaller, and shorter-lived.

 

[Roospike]

JotulOslo , I took you pic and edited the tint to take a closer look at your cap.

Edited pic #1

Pic #2 my pipe and cap.


As mentioned , the cap is going to be a cood spot of the chimney and if it going to collect anywhere ...... its going to happen there.

Could be a combo of some wet/green wood and also being a liner in a brick chimney and or also just the cap design.
looks like you running your stove hot ad whey you mentioned so that dont sound to be the case.
Tho in my pipe cap you cant see the inside of it ......when i clean my chimney i normally have no build up under/inside the cap but i might get a few crusties on the spark screen.

 

[hardwood715]

Here’s the story: I get some splits going and I take the dog out for a tinkle. As I wait for her to choose the perfect spot to pee, a nice big red ember floats down in front of me and lands in a pile of dry fall leaves.

Whoa! Lotta that going round lately, Driftwoods neighbor and his woodpile,(in prior post) Hope I dont fling an ember on my neighbors Chia Pet

 

[Eric Johnson]

The only time I've ever had sparks coming out of my chimney was during a chimney fire. Are you sure you weren't just burning off a little creosote?

 

[Todd]

I have the screen type cap and would never cut away the screen. When this house was my parents, they had no cap, and it seemed every year there was a dead bird, bats or squirrels leftover nuts and stuff in the cleanout. Since the cap nothing. I use to get creosote around the screen with the old noncat stove, but with the new cat stove there has been much less build up.

 

[DriftWood]

Is your flex liner insulated? I am running a new insulated SS 316 TI flex liner (thin stuff) in a north facing masonry chimney for about the same time, with a clean cap.

 

[DriftWood]

Yeah. The underside of the top of both my caps glazed over in nothing flat with no accumulation in the the pipes just under them. I guess I bring'em down in the off season and take the propane torch and light'em off for a little cap cleaning.

On my first setup I would take the cap off, put it in the burning barrel stuffed with news paper throw in some more newsprint lite it to burn off the stuff. I would even BBQ it on a stick (SS Cap Ke-Bab) it over a open fire to burn the stuff. I'm going to try to soak the stuff off my new cap in a bucket of water.