Glazed creosote in three weeks?

[MrAdam]

Hi everyone. We have been burning pretty consistently for about three weeks now. This morning I went on the roof and checked the chimney for buildup. I have a thin layer of glazed tar buildup in the chimney pipe, which I've read is stage 3 glazed creosote. It seems kind of odd to have this glazed buildup already with us only burning for three weeks now. Guess I should include some specifics:

We have a Heatilator WS18 that we installed this fall. I ran the chimney pipe up through roof, with single wall pipe from stove to ceiling adaptor, then insulated double wall through attic and roof. All done according to code here in Missouri. Total length from stove to top cap is 14 feet, with cap three feet above anything within ten feet. Good draft too.

We have been burning wood at about 20% MC, however I've discovered my wife has had the kids bring wood in for daytime firewood(When I'm at work). They were grabbing some pretty green stuff. This maybe happened for a week, then I found out.

Could just that little bit of green wood cause glazed creosote buildup?
Sorry for the long post. Thanks for any and all replies.

 

[claydogg84]

I would say that 1 week of burning somewhat wet wood wouldn't or rather shouldn't give you that hard glaze, but I could be wrong. Are you checking the chimney to see if you're constantly spewing smoke? Or is it burning clean?

 

[Poindexter]

According to Heatilators website your stove is EPA cert, non cat. I have never actually seen one, but you certainly do have a problem now that you can fix before it becomes a disaster. Shiny black stuff is the least desirable of all chimney deposits.

Do you have any elbows or other angle fittings in your flue/chimney piping? If you got 14 feet straight vertical with no angles I would sumrise that all your wood is too wet.

What is probably happening is either because of really cold outside temperatures or angles slowing gas velocity in the stack, or wood being too wet to start with is water vapor is condensing in your stack. When it does condense it gloms onto an ash particle just like snowflakes and raindrops start out glomming onto a tiny piece of dust.

Then black water droplets are hitting the interior wall of your stack and sticking....

First I would encourage you to get a brush and some extension rods. If you think you can get up on your roof safely all winter you can save a few bucks by buying the long stiff rods that match your brush and doing every thing from the top, sounds like you are on a every two week schedule for now. Lowe's and Home-Depot, at least my local ones, both carry everything you need.

If climbing on the roof in January doesn't appeal, you can do it from inside. Cold stove, more expensive shorter sections of "flexible" (a relative term) extension rod. On mine I can hold the telescoping piece of pipe between the stove and the ceiling in the "up" position with blue masking tape while I am working, then punch a hole in the side of a trashbag and tape that to the bottom of the flue. What I want is the brush up in the pipe, the rod coming through the hole in the side of the trashbag and all the crud to end up in the bag instead of on the carpet.

Second, see if you can get some bio-bricks or enviro-logs or etc, basically firewood sized chunks of wood pellet like for pellet stoves. Those generally ship at 12-13% moisture content, throwing one or two of those in with every load of wood might clean up your exhaust enough to get you out of sweeping your chimney so often.

For next year of course split your wood a little smaller so it can dry a little faster... just saying.

 

[Poindexter]

Good idea from claydogg. Ideal would be no visible exhaust within a foot or so of the stack outlet, and then a short plume of condensed water vapor that dissipates pretty quick. That would be complete combustion and good enough stack flow that all the water in the stack leaves the stack as vapor.

 

[begreen]

Green wood can plug a chimney cap screen in a couple weeks, especially if the stove is being run at a low temp. The single wall pipe is further cooling down the flue gases which can lead to condensation when the gases hit the cold exterior portion of the chimney. Is there a thermometer on the stove or flue pipe? If yes, find out what temp the stove is being run during the daytime. It could be your wife is like mine and doesn't like to put more than a few splits of wood on at a time. If the stove top is only in the 300F range and the flue gases are dropping below 250F they are going to condense. If that is the case bring the stove top temps up to 400-500F for a cleaner burn. When in doubt, step outside and look at the chimney. If there's visible grey or black smoke the fire is burning too cool. Pure white smoke when it is very cold outside is actually steam. That is ok.

 

[BrotherBart]

Keep the temps up for a couple of days and check the pipe again. I blew it on the night burn night before last and for the first time ever had a very thin glaze in the top six feet of the pipe. Knew I had screwed up when I got up to smoked glass in the stove and headed for the roof. Turned it down too low, even with bone dry wood. Shutting them all the way down just does not work with most stoves. And I usually don't, but did and paid the price.

Burned it at six hundred stove top with active flames last night and dried it out to soot.

 

[MrAdam]

Thanks everyone for the replies.
Claydogg-the only times I've noticed any smoke from the flue was when I get home from work. That's what alerted me to what the wife/kiddos were doing.

Poindexter-yes, it's a noncat(thanks for taking the time to look it up). I do have an elbow at the top of the single wall pipe(couldn't be avoided due to clearances and ceiling rafters), but it is only about at 12 degree angle. I do have a brush and poles. I'll try your suggestions. No fear of rooftop work. I'll look into getting some bio-logs too.Thank you

Begreen and brotherbart- I wonder if I am burning at too low a temp. I don't have a temp gauge, but I'll try and get one. Haven't yet burned a full load of wood in this stove. Was still kind of feeling out how it works. After reading up more on noncats I'm thinking I need more wood in a load and a hotter fire. I'll try it.

Thanks again everyone. This site has been so helpful in our journey! I appreciate you all!

 

[BSH1F]

Keep the temps up for a couple of days and check the pipe again. I blew it on the night burn night before last and for the first time ever had a very thin glaze in the top six feet of the pipe. Knew I had screwed up when I got up to smoked glass in the stove and headed for the roof. Turned it down too low, even with bone dry wood. Shutting them all the way down just does not work with most stoves. And I usually don't, but did and paid the price.

Burned it at six hundred stove top with active flames last night and dried it out to soot.

So is it safe to say if you keep the glass clean then your chimney should be okay. My first year i burned green poplar and had to clean my glass once a week, and my screen got plugged on top my chimney pipe within 3 months from brand new. Now i know how to run it and i get the Temps up quick and they stay there and i haven't even thought about cleaning my glass because i must be doing it right, right? (Yesterday morning i came down to dirty glass after shutting it down, i just put my head down) 5 weeks clean glass, one night of tiredness ruined my clean streak lol.

 

[MrAdam]

Here's an update, if anyone's interested. This morning I cleaned our chimney, using a 6" nylon(I think) chimney brush. Pleased to report that the shiny black tar that once coated the top of the chimney was now a crusty brittle layer that brushed off with a little effort. After the cleaning the inside looked great. Running hotter fires, less green wood (translated:kids don't load firebox) and not damping down all the way really helped.

Thanks to everyone for the suggestions. Love this site!

 

[CenterTree]

Don't ya just love it here?

 

[begreen]

Good news. Pick up a stove top thermometer. It's easier to teach the family how to burn when they have some extra guidance.