Softwood tarring up flues?

[doobin]

I simply must have hardwood for my Scandinavian designed wood burning stove!

 

Love softwood, I keep it to one side for the workshop burner supply.

[shavey]

No worries mate. They'll be changing their thoughts when the price of burning hardwood goes through the roof.

 

yes thats true hopefully they will get the message money is the only way that will change their veiws after all softwood is much easier to process and you can turn it around quicker if you have it stored right :thumbup:

[renewablejohn]

Had this conversation with Esse design engineer on our Esse range cooker. We where guinea pigs and told the stove would burn any hardwood or softwood. After 3 months on softwood stove completely coked up with tar and design engineer called in to verify what went wrong. Totally decoked and new test on softwood max 20% MC after 3 months stove stripped no tarring whatsoever only a fine dusting of grey ash. Esse now specify in their handbook logs must be maximum of 20% moisture content.

[difflock]

Well DERP!!

As wor son is wont to say.

Why or how on earth did Esse imagine they could produce a stove/cooker to burn ANY wood, regardless of M/C ,without problems.

Unless they had a supplementary gas burner plumbed in.

m

[SteveA]

Had this conversation with Esse design engineer on our Esse range cooker. We where guinea pigs and told the stove would burn any hardwood or softwood. After 3 months on softwood stove completely coked up with tar and design engineer called in to verify what went wrong. Totally decoked and new test on softwood max 20% MC after 3 months stove stripped no tarring whatsoever only a fine dusting of grey ash. Esse now specify in their handbook logs must be maximum of 20% moisture content.

 

Further proof, cheers

[StephF]

Will you guys please stop bigging up softwoods as firewood, pretty soon everyone will want it. Stop it!

 

I am suffering (wrong word) from this problem already! local Green energy shop selling stoves has been so good at promoting softwood as sustainable etc, and our web site has all the pro softwood stuff on it that we cant cut and prepare enough! I've got a lovely barn of dry hardwood that I am forcing prople to buy, telling them it is amazing mixed in with softwood..

Feed-back on the softwood is often along the lines of how much better/easier it burns than the hardwood they have previously bought elsewhere. I think it is because it is well seasoned and dry, and maybe H/W was not.

On the matter of research into tar: on our web site is a photo of inside my Esse cooker that burns 24/7 on softwood and is as clean as a whistle!!

[Alycidon]

Had this conversation with Esse design engineer on our Esse range cooker. We where guinea pigs and told the stove would burn any hardwood or softwood. After 3 months on softwood stove completely coked up with tar and design engineer called in to verify what went wrong. Totally decoked and new test on softwood max 20% MC after 3 months stove stripped no tarring whatsoever only a fine dusting of grey ash. Esse now specify in their handbook logs must be maximum of 20% moisture content.

 

 

Most stove manufacturers say 18%, some 16%, MAXIMUM.

 

Went out to an Esse stove I supplied a couple of weeks ago last night, on delivery guy said he had his own wood supply but I left my usual firewood info package which goes to some length about MCs.

 

His logs were 40% - 45% MC, looks like they had been bought from a local garage. Took some of mine at 12%, cleaned it up and away it went.

 

A

[sandspider]

Anecdotal evidence only, but I've been burning more softwood this year - mainly old conifer roof trusses / builder's waste. This is mixed with hardwood and whatever else I can find and dry (a fair bit of silver birch, some cherry etc.). I have noticed actual chunks of tarry clinker dropping out of the chimney / stove, and don't remember seeing that previously.

 

I don't leave it in overnight, though it does idle a bit towards the end of the night when I stop feeding it. I say anecdotal as I'm not sure how dry the other bits and pieces I feed it are (still seems to be a bit of moisture in some of the cherry, though it's cracking), and I'm not positive there wasn't some clinker drop last year! Just seems more noticeable this year...

[SteveA]

Anecdotal evidence only, but I've been burning more softwood this year - mainly old conifer roof trusses / builder's waste. This is mixed with hardwood and whatever else I can find and dry (a fair bit of silver birch, some cherry etc.). I have noticed actual chunks of tarry clinker dropping out of the chimney / stove, and don't remember seeing that previously.

 

I don't leave it in overnight, though it does idle a bit towards the end of the night when I stop feeding it. I say anecdotal as I'm not sure how dry the other bits and pieces I feed it are (still seems to be a bit of moisture in some of the cherry, though it's cracking), and I'm not positive there wasn't some clinker drop last year! Just seems more noticeable this year...

 

By throwing in occasional moist logs you would be drawing energy (heat) out of the whole fire which can lead to an inefficient burn - over time this could be producing what you describe as tarry clinkers.

 

What do you mean by "builders waste"?.... if it's what I'm thinking; best to steer clear of burning any pressure treated timber. Burning pressure treated wood could also be contributing to producing your tarry clinkers? It can also make some pretty serious crackling & spitting embers! (I've tried this myself) Cheers, steve

Edited March 7, 2014 by SteveA

[sandspider]

Thanks Steve

 

It's not occasional moist logs, it's just that I've noticed a bit of moisture coming from 2 of the cherry logs I put on - dried for a year, and cracking, but still with a bit of residual moisture. Stove is still too hot to touch, and can burn through welders gauntlets when opening the door!

 

When I say builder's waste I mean old roof beams (100 years plus) and that kind of thing. Don't think they were pressure treating then, though I suppose some of it might be. Does have a bit of crackle and spit from time to time, if I put them on to very hot coals. Does pressure treating trap sap in the wood or similar? I haven't burnt this volume of builder's waste before, so that could be a contributing factor.