Creasote on underside of cap

  • 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.

AnalogKid

Burning Hunk
Oct 22, 2012
229
CT
Preface....So I had my new insert installed around mid-Nov and have been burning just about 24/7 since. My typical burning rhythm is a full load every 8hrs; load up around 11pm, load up around 7am, load up around 3pm, and so on.

When the stove is at the end of a burn cycle towards it's 8th hour, the stove-top temp is usually between 250-300 degrees. Then I load up, door cracked if need be for a few mins, air wide open, get the stove-top temp to 600 degree then scale the air back. Throughout the duration of the burn I would say the average stove-top temp is between 425-475 degrees. The wood I have been burning is all >20mc.

The height of my chimney from base of firebox to top of chimney is 12'5". Yes, a shorty. My cap is a large, 3-flue metal cap. The clearance from the top of the chimney to the underside of the cap is about 6".

Yesterday, for the heck of it, I got up on my roof to take a look at chimney crown, cap, etc. Flat roof, real easy to do. Well I was a bit shocked to see the underside of the cap coated in a significant layer of creasote! I did not remove the cap and look down the chimney because I was burning at the time. Is this something I should be concerned with? If the underside of my cap is coated, does this mean my liner is just as bad? The liner by the way, is single wall SS flex pipe with a double layer wrap of 1/2" insulation.

I would really appreciate some feedback from some burning vets. Thanks guys.
 
I would think the cap is a good indication of what the liner looks like. Let the stove cool and do a thourough cleaning so you can be sure your burning safe.
 
If the underside of my cap is coated, does this mean my liner is just as bad?

Not necessarily so with an average temp of 425-475...that's a good hot # for us. Chimney caps can collect creosote because the smoke is cooler at that end and many caps are too restrictive.

Is is possible for you to burn without a cap?

After this storm perhaps you can mirror the chimney from the clean-out to find out for sure.
 
If the underside of my cap is coated, does this mean my liner is just as bad?

Not necessarily so with an average temp of 425-475...that's a good hot # for us. Chimney caps can collect creosote because the smoke is cooler at that end and many caps are too restrictive.

Is is possible for you to burn without a cap?

After this storm perhaps you can mirror the chimney from the clean-out to find out for sure.
Agreed! The cap is subject to more elements than the rest of the liner. Rainy days and snow could cause the most profound cooling effects.
 
Unfortunately I need the cap to be in place. I don't have a clean out to check the chimney, but since it is so short I can see really well all the way down with the help of a flashlight.

I feel good with the idea of the cap just being so much cooler. The rain/snow comment makes sense too since when it does rain or snow and I am burning hot, the cap will put off steam as the water evaporates.

I would think, with such a short chimney, combined with being double wrapped with insulation and burning plenty hot enough that the insert pipe should stay plenty hot to void off large amounts of creosote production.

Thanks guys.
 
I agree with the cap being at the end of the run, cooler, smoke is going to condense on the underside of the cap...On my Esse cook stove pipe I can go out side look up the bottom of the clean out tee to see nice brown fine fluff,, yet the cap has some build up underneath... It just falls off and winds up and the tee clean out cap.. The cap is also not a dripping mess either,,that would seem to be an issue then..
 
Yea that cap has a 6" space really that seperates it from the liner, with it being a tripple cover its got 2 flues worth of metal without heat under it causing it to cool the side over your liner. With it sitting 6"s higher and the gasses being cooler at the top anyway i would think that creosote would not be a hard thing to have on it, esp in a cool rain like when its 40-50F outside that cap is going to be pretty cold having that warm moist air hitting it, to cause the creosote to condense and form on it.

If it was like my neighbor that pretty much burns 24/7 in his 20-30 year old stove and "said he never cleans his chimny", and has about a 3'' long creosote sickle that i can see hanging off of it i would be more concerned!!!
 
  • Like
Reactions: charly
Status
Not open for further replies.