Softwood tarring up flues?

[StephF]

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

 

Good to here you had success with dryer logs, ours only burns dry S/W and is very clean. I had a go at Esse as they go on about hardwood, when they should be emphasising the moisture content as most important!

[SteveA]

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.

 

I think maybe the Cherry logs aren't seasoned enough.

I've found even by burning fairly moist logs the fire will still radiate very hot (at least that's what it feels like to our skin) and with lots of heat being thrown out into the room. But this doesn't necessarily mean the fire is burning efficiently enough to stop unburnt hydrocarbons lining the flue.

 

The timbers I burnt came from a house built in 1860.... it was verging on dangerous, explosive!

Good question, I'm not sure if pressure treated wood traps moisture in? As far as I'm aware the pressure treatment is done at a specific moisture range/ level according to the wood type. Presumably the majority of moisture would evaporate out of the timber over time (especially when left indoors). But pressure treated timber can still absorb plenty of moisture, so it's not a one way affair.

 

Cheers, Steve

[Stubby]

I think pressure treated timber , pallets etc , its what they put in not so much what they trap ...

[renewablejohn]

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

 

At the time Esse had a real problem with a well known country magazine really slagging off their at the time new cooking stove which clogged up at the drop of a hat. All down to moisture content not activating the after burner technology.

[Alycidon]

Good to here you had success with dryer logs, ours only burns dry S/W and is very clean. I had a go at Esse as they go on about hardwood, when they should be emphasising the moisture content as most important!

 

Esse and David Randleson their chief tech guy who has been there for ever are a good genuine company. They do rely on their dealers to drive home the message on MCs but if buying on line (and there is no reason for that as the local dealer is not far out) customers do not get the benefit of that advice or any support if issues occur.

 

A

[woody3]

used to only burn hardwood, now only burn softwood,fire is shut off all the time, no tarring

[hedgesparrow]

i have burnt softwood on our stove and been ok its been seasond. for over 2 years so bone dry. sweep came out and swept chimney hardly any soot came out. so will burn softwood when its dry.

[kev7937]

Nick hits the nail on the head. It's the moisture that matters - when vapourised it kills the secondary burn; that then condenses as tar; flue clogs up; fire risk starts.

 

 

Agreed.

 

The thread starter talks about softwood generally, all woods except possibly one will not give an issue if dry, ( below 14%).

 

The one I have reservations about is Pine. Put in on a stove and you can see the resins coming out of the log after about 5 mins, burns like fury, clags up the glass like billyo ( I did post on this subject) even when the stove is correctly set up.

 

I have burnt quite a bit of Pine earlier in the winter, as far as I am aware I have no issues with tar but I wont know for sure until I sweep the flue in a few weeks. I would not be surprised to find some tar present.

 

A

 

 

But if the stove is set up correctly and burning hot enough then surely the resins will all combust in the secondary burn ? You can ignite a resinous log with a match straight from the tree so why wouldn't they burn in a super efficient stove?

[Alycidon]

 

 

But if the stove is set up correctly and burning hot enough then surely the resins will all combust in the secondary burn ? You can ignite a resinous log with a match straight from the tree so why wouldn't they burn in a super efficient stove?

 

You would have thought so but it certainly clags up the glass on my Morso Panther, no other wood does that. Remains to be seen what in the flue liner.

 

A

[Dodge]

The times I have had this conversation with log snobs I now tell them that the only safe thing to burn is smokeless

while I get all the wood !!!

 

I burn any type of wood I can get my hands on, this week I am going to be splitting a load of conifer and yew last week it was cherry, when I had my stainless steel insulated liner swept it was as in the sweeps words "as clean as a whistle" very little soot and no tarring and last year prior to it being swept I would say 60% of my burning was softwood.

 

I always run my fire hot because if you notice ( clear view fire ) if the fire is on close down / slumber the glass blackens and this must get replicated up the chimney and then the fun starts, so just watch your glass I say

(with a clear view anyway )