Switching off the wood burner

So we all know have only recently learned that wood burner should be run above 110 degrees C to prevent creosote buildup.

Obviously when starting the fire, get it up to temperature asap.

What about when you’re going to bed? Leave it with sufficient air to burn away the remaining fuel, or close the air vents so it drops more quickly through the creosote zone back to room temp?

Probably depends what it’s doing for your household heating? Is it being used to heat where you sleep?

Just let it burn itself out.

Can’t you just set the thermostat and leave it?

We just leave it as it is, usually with the air half open as that’s where it will have been when it’s burning well.

Only thing we were warned against was stocking it right up and closing the air in the hope of still having heat in the morning.

Disclaimer: new log burnerist.

Rene – assume I don’t want any more heat at this point

Wood burners are at their most ‘dangerous’ in terms of co output when shut down or left to burn out.

Always purge the stove before going to bed, in other words, open the air vents fully and let it burn out at max temp.

That way, there’s much less chance of children, baby robins and kittens dying to death.

Wood burners are at their most ‘dangerous’ in terms of co output when shut down or left to burn out.

Yet sitting in front of one some how makes the CO less dangerous.

I do do same, open all the vents to maximum and leave it to burn out fully/quickly. The other thing is not to put a log on it <30 min before you’re about to go to bed (obviously)

Same here, open vents up. If there is lots of fuel left I just open them up enough to ensure it burns quickly, I don’t want it running away whilst I am in bed 🙂

I don’t see the point in building the fire up to try and keep it in overnight, tried it once and woke up to black glass and hot ashes so it still needed kindling and paper to get it going again, and then a clean up once it was cold. (mine has never seen a lump of coal which presumably will stay in overnight easily)

Aye, open up vents.

I never feel comfortable heading off to bed if the burner is still going, however irrational that might be. So another +1 for opening up the vents about an hour before that to make sure there is no fuel left.

Burn it out… don’t leave any fuel in it when you head to bed. Why would you?

I always open up all the vents are let it burn out as fast as possible. I quite often throw an extra log on for the benefit of the cats….

I just leave ours to burn out, but by that stage there’s nothing but a glowing pile of ashes left anyway and therefore little/no creosote.

It surprises me how many people do not have a stove thermometer. We have them on all of ours and I’d feel uncomfortable using them without one. I always aim for >200c although my newly bought IR thermometer thingy shows that an indicated 200 is actually more like 170c.

The biggest cause of creosote, though, is damp wood. I’m lucky in that we have the space and resources to process a fair bit of wood and so the stuff we’re burning right now is at least 2 years old and each winters wood is moved inside at the end of September. I’m currently splitting wood for use in 2022/23.

Wood burners are at their most ‘dangerous’ in terms of co output when shut down or left to burn out.

Yet sitting in front of one some how makes the CO less dangerous.

When someone is sat in front of the fire, they tend to notice when the flames have gone down / stopped and their colour, and either put more fuel on or open it up. If you ‘shut down’ the fire you reduce the oxygen leading to more CO and a cooler fire, similarly if you leave it burning then it will pass through the cooler phase more slowly. As everyone has said, you should open up the burner to burn down the fuel quickly at the end of ghe night. Keep the flue hot and have yellow flames to minimise creosote and CO. Unburnt fuel is bad.

Ours runs 24/7 for 5 months through the winter. It also has a back boiler and does the central heating for the house. I make it up before bed, close it down a bit, then in the morning throw on a few logs and lit it rip until it has had a good hard flame, before shutting it back for the rest of the day. I do clean my chimney every few months mind. 🙂

vents open to drag last bit of heat out quickly..

Flat out with dry wood. At all times. Felling it quicker than I can burn it, have to sell the excess to sawmills 😉

^^^ Bastard!

If you ‘shut down’ the fire you reduce the oxygen leading to more CO and a cooler fire

If I shut down the vents then (despite being defra approved vents which don’t fully shut) the fire just goes out, leaving unburned fuel.

there’s nothing but a glowing pile of ashes left anyway and therefore little/no creosote

Hadn’t thought of this – so mostly burned wood will not release creosote? in which case opening up makes sense like you say

I always aim for >200c although my newly bought IR thermometer thingy shows that an indicated 200 is actually more like 170c.

Cheap thermometer is designed to over read as the outside of stove pipe is cooler than gases inside perhaps?

Also, 200. Holy flipping sugar. Starting to think 5kw burner was overkill for our 4x6m room as we’re quite warm enough at 110 thank you very much! (official calculator says 4.6 is ideal, which is the right ballpark – I’m quite surprised)

No need for a thermometer, unless maybe a beginner? Stove fan only rattles round at full tilt if it’s up to temp, I like a good strong burn too, no way I’d let mine dull down.

My fan starts spinning at around 50 deg on the IR thermometer, but most of the time I just lick my finger and touch the top, if it sizzles we’re all good, if it doesn’t, but feels good and hot then not too bothered, other than that bung a log on/ open vents.
I agree that stoves should burn hot, and open the vents before bed.

No need for a thermometer, unless maybe a beginner? Stove fan only rattles round at full tilt if it’s up to temp

12 years of stove use…. not sure I’m a beginner but I do like to use it properly.

Your stove fan is your ‘thermometer’ – I presume if it’s not spinning you know that the stove isn’t hot enough.
If we used fans we wouldn’t use the thermometer.

And I thought this was going to be a thread about permanently switching off the log burner now that we are aware they are really really bad for the environment

That aside, burning cold isn’t good for chimney liners, basically leaving it to burn out is doing this

leaving it to burn out is doing this

leaving it to burn out is ambiguous. you mean vents open (takes longer, maybe less sooty) or closed (stops burning pretty quick)?

Anyone got a link to anything reasonably scientific that says it’s better to leave the vents open at night – I’ve not found anything yet.

Is this why the Scandinavians and their rocket style stoves with massive thermal mass work so much more efficiently than our stoves designed to look nice with flames and all that jazz?

I personally am still planning a self build with a massive thermal mass rocket stove in the middle, one day…

I’m with sharkbait on all he said… His post read like I was about to write. Although I aim for as close to 260C as possible if there are flames. Flames are the volatiles, unburnt volatiles is smoke, condensed smoke is creosote, so burn hot. Once the wood had coaled there is no smoke or creosote so you can allow a cooler burn of the coals.

Regular short hot excursions may clear the flue of any condensate…. And clears any trace muck from the glass, don’t be scared to throw a couple of small splits on and let it rip through them every now and then.

Matt, I believe the old Scandi stoves were huge as they cooked in them also – but that said they’re now into ‘stone’ stoves which will absorb more heat (and radiate it for longer) but I’m guessing that they take longer to heat up initially – this would not be a problem though if it’s run 24 x 7.

don’t be scared to throw a couple of small splits on and let it rip through them every now and then.

Lost track of the number of times I’ve lit it and forgot to turn it down after 20 mins and come back to see the thermometer needle off the end of the scale (only goes up to 400C)….

but I’m guessing that they take longer to heat up initially – this would not be a problem though if it’s run 24 x 7

Nope. They burn them a few hours a day, then leave the big stone to radiate that heat through the day…

I get nervous as the needle heads north of 400 but the steel the stove is ok well beyond that. I don’t aim that high though, but do regularly send it to 325-350C for a short while. Small splits and just a couple, then it burns or and chimes back down in temp relatively quickly. I quite like doing it at the end of the burn, clear the flue and ensure its properly warm to keep a draft going when the stove itself has little fuel left. That continued draft ensures the CO goes up the flue.

Fair enough Matt …. interesting concept.

Edit:
A quick google has shown this on the Contura web site:
https://www.contura.eu/english/facts-tips/heat-retention/

2.5hr burning time – very interesting!

Although they fact that they also produce a wide variety of ‘standard’ stoves, as we would know them, would indicate that this is not the only way stoves are used there.

One of our stoves is an inset into a stone fireplace. Although the stove does not give out the same amount of heat into the room as a standalone stove, it does put a fair amount into the surrounding fireplace and brickwork which keeps emitting heat well into the day after the stove was run.

Actually Matt I’m not sure they use a ‘rocket’ stove type effect as I’ve found that if I leave the bottom air feed open too long that [although the wood is burning very fast] the heat is mostly just going up the flue rather than soaking into the stove.

A well designed stove will burn cleaner and more efficiently on the lowest setting because it allows gases in the wood to escape and burn before going up the chimney.
If you burn a stove at full chat you are wasting fuel or is it because your fuel is not dry enough!

I’ll dig out a picture, but the Swiss and Swedish ones I saw were huge. Proper big heat sink – and the theory was to burn as efficiently as possible – and that was HOT as possible, then moderate the heat getting into room. At 7am, after fire went out by midday the previous day, the room was still warm and the stove really warm still to touch.

Bigger than this…
http://www.greenstoneheat.com/wp-content/uploads/2017/06/SoapstoneMasonryHeater-Ricota-6-Oi-new.jpg

Here is a couple. The ones I saw were tiled finish.

Psst, there is this thing such as gas central heating – goes on and off when you want, and there is even extra wizzardry available now, where you can switch it on when away from home. It will never catch on you know. 🙂

Central heating is only a bodge for lack of insulation and efficiency measures. 😉