Help with chimney smoke!

[Jambofork]

Hi all - I’ve made an account here in the hopes I’ll get some guidance on a stove I have inherited.

I’m having issues with smoke from the chimney. I am burning kiln dried wood (moisture checked to 11%) at the correct temps (as far as I can tell with thermometer) and the chimney was swept only a month or so ago. So I am stumped. Maybe this amount of smoke is normal but everywhere I read says very minimal smoke or white steam like smoke. I am getting very dark nearly black smoke which forums are telling me I am burning something incorrectly or worse something toxic - which I am definitely not).

The smoke does seem to clear somewhat once the fire has burned down a bit so maybe I am just paranoid but it does seem a lot more than I would expect. I live in a smoke controlled area but I am more concerned about what’s happening inside my chimney with the colour of smoke - if something awry is going on and I am at risk of chimney fire.

One other relevant thing to post is that the chimney was extended very recently and the exisitng flue had an extension piece of flue connected to original flue length, fire cemented together, then the stone masonry was built up. I don’t know if the existing masonry which is very old is maybe dirty and heating up old soot to cause smoke? Or the guys who done the chimney extension have cocked it up somehow?? Mind I don’t know how you’d cock that up. Chimney sweep seems to think it’s grand and to burn away but it keeps bothering me.

Posted some pics of fire box, temp reading and a couple of the smoke being produced in real time.

Help appreciated - even if it’s just telling me this is normal!

 

[begreen]

Many stoves sold in the UK lack secondary reburn technology to clean up smoke. What is the stove make and model?

 

[Jambofork]

Many stoves sold in the UK lack secondary reburn technology to clean up smoke. What is the stove make and model?

Hi - it’s an aspect eco 4 I believe - which does have secondary and tertiary burn according to manual and allowed to be fitted in smoke control area.

 

[begreen]

Once the fire is burning strongly is the air control being lowered to a very low amount, like only 5-10% open, or enough to make the flames lazy, but not out?

 

[Jambofork]

Once the fire is burning strongly is the air control being lowered to a very low amount, like only 5-10% open, or enough to make the flames lazy, but not out?

I am lowering the air control once I am getting white ash and the fire is up to temp but not fully closing. If I put it down to lazy flames I get more smoke if anything. I think it’s hard to tell - I did think maybe it’s too much draw and the secondary combustion isn’t having a chance to burn off the gases - not sure.

 

[armanidog]

I looked at the manual. On page 14 "Notes On Woodburning"'
"With a full load of wood the stove will need to be refueled approximately once every hour. Wood can be stacked in the stove but no higher than the tertiary holes in the back of the firebox.
Overloading the stove will cause excess smoke to be emitted.

(And also)

If there is insufficient burning material in the fire bed to light a new fuel charge, excessive smoke emission can occur. "
User manual
https://www.directstoves.com/parkray-aspect-4-compact-wood-burning-stove.html ( User manual is a pdf.)

 

[Jambofork]

I looked at the manual. On page 14 "Notes On Woodburning"'
"With a full load of wood the stove will need to be refueled approximately once every hour. Wood can be stacked in the stove but no higher than the tertiary holes in the back of the firebox.
Overloading the stove will cause excess smoke to be emitted.

(And also)

If there is insufficient burning material in the fire bed to light a new fuel charge, excessive smoke emission can occur. "
User manual
https://www.directstoves.com/parkray-aspect-4-compact-wood-burning-stove.html ( User manual is a pdf.)

Thanks for the reply. This the first load I put in - maybe this is just how much it smokes when lighting up and refuelling - does seem a lot.

The tertiary holes are not covered in pics and the fuel amount is below the weight limit for firebox guidelines

 

[Jambofork]

Here are some other pics from the same fuel burn but slightly later on and with air controls open for longer fire burning hotter. Less smoke definitely - sorry hard to see in pics but still some dark/black puffs of smoke but not streaming.

Maybe I’m just being mental!

 

[Prometeo]

you have to reduce the air that comes from below ( primary ) this will allow the secondary to burn cleaner.

 

[begreen]

How dry is the firewood? The best design is going to smoke if the wood is too damp inside.

In the manual, they confuse terminology. It looks like they are calling "secondary air" the airwash which is actually still primary air. They call primary air what we call boost air, which is directed at the bed of the fire. The tertiary air is what we know as secondary air. It is located at the back of the firebox. My impression is that this setup is not going to do a good job of burning smoke that is coming from the front of the fire and straight up past the baffle.

 

[Jambofork]

How dry is the firewood? The best design is going to smoke if the wood is too damp inside.

In the manual, they confuse terminology. It looks like they are calling "secondary air" the airwash which is actually still primary air. They call primary air what we call boost air, which is directed at the bed of the fire. The tertiary air is what we know as secondary air. It is located at the back of the firebox. My impression is that this setup is not going to do a good job of burning smoke that is coming from the front of the fire and straight up past the baffle.

Hi Begreen - it’s kiln dried and I even bought a moisture meter to check and reading at 11% bought in sealed bags and left to dry out further in the house before burning so it isn’t the wood. Do you agree this isn’t a normal amount of smoke - even when starting a fire from cold?

 

[stoveliker]

did you re-split the wood to check the inside, or did you measure on the outside?
If you can't resplit the wood, AND you measured on the outside, how thick are the splits, and what species was it?

I do think splits there are sold generally fairly thin (to our customs), and that there are rules on your side of the ocean about selling wood dry enough, so I think it's likely (not 11%, because I think that was measured on the outside, but) less than 20%, but it's good to verify.

 

[begreen]

Hi Begreen - it’s kiln dried and I even bought a moisture meter to check and reading at 11% bought in sealed bags and left to dry out further in the house before burning so it isn’t the wood. Do you agree this isn’t a normal amount of smoke - even when starting a fire from cold?

Yes, I wouldn't be happy if a stove smoked like that after it was up to temperature.

 

[Jambofork]

did you re-split the wood to check the inside, or did you measure on the outside?
If you can't resplit the wood, AND you measured on the outside, how thick are the splits, and what species was it?

I do think splits there are sold generally fairly thin (to our customs), and that there are rules on your side of the ocean about selling wood dry enough, so I think it's likely (not 11%, because I think that was measured on the outside, but) less than 20%, but it's good to verify.

Hi Stoveliker

This is the manufacturer we buy from - seems mostly oak but can be a mix of hardwood. I am certain the wood is below 20%

The splits are small are relatively small

Kiln Dried Logs for Firewood | CW

Kiln dried logs, kiln dried kindling and Firelighters, from sustainably sourced woodland in Britain. Pioneers of kiln dried firewood.

www.certainlywood.co.uk

 

[Rickb]

Generally kiln dried here is crap for burning for a year or more. Its brought up to temp to kill bugs and stuff but still wet inside. Resplit a piece and check it.,

 

[stoveliker]

In the UK I suspect that (kiln drying) is different. Probably firewood sellers even are permitted and have to be below 20%.

BUT, I see on their website that it's below 20%. I'd call them and ask them how that was determined. (Because if that's on the outside, then it's not good enough.)
I think there's a good chance the wood is good. But that smoke does look like a lot.

 

[stoveliker]

Their website says "It takes a long time to season wood naturally – up to three years. Be careful when buying your logs and make sure you get a full understanding of the quality you are buying. Many suppliers will claim the wood has been ‘down’ for two years and therefore dry. That does not mean it’s dry. It is not about the time the tree has been cut down, but more about how the wood is stored. It must be sawn into log size, split and stored under cover for meaningful seasoning to take place. The best thing to do is check the moisture on delivery with a moisture meter."

That remarks on storage and drying are all exactly right .

I think it's the system, and not the fuel.