Logburner Advice

[88v8]

Has anyone got one of these? They're cheaper on e-bay...about £50 or so... 8)

http://www.irelandstoves.ie/index.php?route=product/category&path=40

There is a Chinese copy on eBay, the originals are made in Canada.
Ingenious contraption, powered by a peltier.
http://en.wikipedia.org/wiki/Thermoelectric_effect

The temperature difference is created by the bottom of the peltier being heated through contact with the stove, while the top is cooled by the fins which act as a heatsink.

We have one. It worked well on our old stove, gave a good woosh of warm air and was worth having.
Then we replaced the old stove with a Clearview. Its top gets very hot, and on there the fan works too well. A veritable gale of air, so much so that it actually seems to blow cold.
So we moved it onto the Esse which, strangely, emits very little heat through the top such that the fan takes about an hour to get going and then delivers no more than a lethargic waft. So in the end for us it turned out to be an expensive gimmick.
But they can be good on some stoves.

Ivor

 

[Flyfisher]

Peltier modules are fun devices. Put electrical power across them and they'll cool down (as used in portable drinks coolers etc) but put heat across them and they generate electricity.

I was going to buy one of those 'ecofans' but decided to have a go at making one. I bought a couple of peltier modules on ebay for just under a tenner. I fabricated a crude stand to sit on the stove and sanwiched the peltier module (the white thing in the photo) between it and a CPU cooler from an old PC. The stand gets hot from the stove but the CPU cooler keeps the upper side of the peltier module a bit cooler, thus generating about 1.7 volts. I connected it to a small electric motor and hey presto! The fan blades were the trickiest bit to make and I settled on cutting down an aluminium drinks can and crudely bending the resulting strips into an approximation of fan blades.

It works, but I confess it doesn't generate too much of a draft. This is a combination, I think, of inefficient fan blades and a slower rotation than the commercial ones I've seen. I suspect the slowish speed is due to the CPU cooler not keeping the upper side of the peltier module cool enough such that it only generates a small voltage. I may play around with it and try a more efficient cooling arrangement or use two modules in series or try both. Or not. :lol:

 

[88v8]

Clever. What's the base made of?
Perhaps the fan blades are a rather coarse pitch? It might be stalling.
Did you put heat paste on the peltier?

Ivor

 

[Flyfisher]

The base is made from some bits of mild steel I welded together. The peculiar shape is because I had to counterbalance the CPU cooler, which is not really the ideal shape for this purpose. I did use thermal past on both sides of the peliter module.

You could be right about the fan blades stalling though.

The other problem, I think, is that because the fan is not moving much air the cooling fins of the heatsink are not really working, so both sides of the peltier module get hot, reducing the voltage output.

Still, it keeps me out of trouble.

 

[middi]

The stacking trick I learnt on a holiday on a game reserve in South Africa. The nice ladies came and lit the braai (barbeque) by stacking 3" logs in this manner and just lighting a bit of kindling in the middle - the effect was amazing! Mind you, 35degree daytime temperatures helped with drying the wood! Wood is the staple cooking fuel amongst the locals so obviously they get a lot more practice than we do and the impact of it not working would be more severe.

I saw a similar sort of skill in Uganda: somehow the local women could keep a fire burning using three long bits of split eucalyptus arranged like a three-bladed aeroplane propeller with the fire at the hub, slowly moving each piece of wood into the centre as required. This was a standard practice for cooking outdoors; even wood is precious there!

The most amazing chimney log fire I have ever seen was when I visited an friend of a friend home in 1973 in Braintree, Essex.
The front door only opened half way due to a wooden telephone pole about one foot in diameter obstructing the entry.
this 'pole was at a slight angle along the entry hall through a doorway, about 12 feet across into another room and into a chimney opening, the tip of the pole happily burning away without any other wood in sight ( due to the creosote cover I presumed !!) .
I said to the chap that the rather unorthodox approach may keep him warm but it was a bit dangerous, he promptly replied that he had already burned one last month and he had another two in the back garden and also added that he worked all the hours under the sun and had no time to waste in cutting it when all he had to do is keep feeding it into the fire.
( I was quite happy that I would be sleeping in my own home that night !!!! )
Middi

 

[Feltwell]

Have you ever seen the big "farm boilers" you can get? A farm-cum-B&B that I know uses one, the owner just chucks whole pallets in, no cutting up required! He did quite well out of the local electricity board, when they were busy replacing wooden poles he gave the work crew £20 for each load of old poles they brought him, though they did need cutting up first! They burned for ages.

http://www.farm2000.co.uk/farm2000.co.uk/Fuels_&_Boiler_Type.html

 

[masochists-r-us]

We run two log burners plus partial central heating.
In line with others, key thing are to prep with plenty of tightly rolled newspaper, topped with a pile of kindling and one well seasoned log only,lit with a firelighter. Make sure you have all your air vents open and keep them so until you have really good blaze going.You can then gradually reduce the amount of air as the fire takes hold. Don't be tempted to fill the firebox with logs until the fire is glowing red hot. We have used wood only until last winter when our wood source was exhausted early so moved on to coal. We now find a combination of the two is ideal. The benefit of coal is that it lasts much longer than wood and will enable you to keep your burners going all night, if that's what you need.

 

[Zebra]

My flue thermometer arrived the other day. Interestingly, it turns out I've mostly been running my stove too cold. I've been letting it glow rather than blaze, but this doesn't get the flue into the "optimum performance" zone.

 

[tobydog]

Bad news regarding our log burner. Yesterday the screwed down plate that covers the optional top flue exit ho!e cracked. The fire was cooling down at the time (still hot) when I heard a loud crack sound. The plate has three screws and it had cracked around one of them. It has raised / warped slighly. I'm not using it due to the risk of fumes leaking but is it fixable?. I would guess the plate is a standard size but I would even consider a permanent fix (welding) because we will never use this exit hole. Does anyone have any advice they can give here?. Thanks.

 

[88v8]

Bad news regarding our log burner. Yesterday the screwed down plate that covers the optional top flue exit ho!e cracked. The fire was cooling down at the time (still hot) when I heard a loud crack sound. The plate has three screws and it had cracked around one of them. It has raised / warped slighly. I'm not using it due to the risk of fumes leaking but is it fixable?. I would guess the plate is a standard size but I would even consider a permanent fix (welding) because we will never use this exit hole. Does anyone have any advice they can give here?. Thanks.

Very hard to weld cast iron, if that's what it is. Especially as it must be flat to seal.
I'd buy a new plate, or make one in (thick) steel.

Edit: I doubt there will be any leakage - try it. I think the pull up the chimney will prevent that. More so I would expect that if there is a leak, it will be air in, which may make it burn faster than usual.
For a temporary repair could you use a longer bolt with a large washer on top to clamp the broken pieces down ? No need to do the bolts up very tight.

Ivor

 

[tobydog]

Thanks Ivor. The plate was also sealed with some kind of oven / burner cement and that's now popped out. That's why I was concerned about leakage. I'll take the plate out and see if I can re-seat it. If it's too bad I'll try and get a new plate. Could have done with it last night .

 

[DJH]

A ring of soft 'asbestos' rope, if that's what it's still called, will do the trick with some longer screws loosely tightened. Fire cement is a bit restrictive and is probably the reason why the plate cracked as it was held too firmly in place.

This is our little whole house warmer in the kitchen and was lit about an hour ago. Must take out those ashes now...



Doug

PS The tray with the ashes in is Mrs DJH's idea. She keeps it (a baking tray) under the stove and pulls it out when either refuelling the stove or emptying the ashtray and it catches anything that drops down. It also serves to dry out wet kindling ready for relighting the fire...simples

 

[Penners]

scrunch up eight to ten sheets of newspaper, put some kindling on top, and one small log, light it, shut the door with all vents open, maximum air flow. I wait until it's got a bit of a glow - some heat in there - a bit of a heart, then load it up full with logs, shut the door again, wait a bit for it to get hot again, then shut the vents down so that a minimal amount of air goes through, and then it burns slowly for hours.

That's the way to do it. There's a lot of hokum talked about wood burners, in my view. Mysterious rites involving grilles/no grilles, bed-of-ash/no bed-of-ash... and so on. I don't find that any of those alternatives makes a jot of difference.

As our stripey friend says, you simply need to use newspaper, kindling, firelighters - whatever will get a good roaring fire started - and then pile in the logs (which of course must be well dried). Then just fiddle with the vents until you get the right balance between heat output and burn duration.

Wood should burn perfectly well with either the bottom or the top vents open, but the top ones should (theoretically) keep the glass cleaner, through a system known as "air wash".

Above all else, your logs must be well dried.

 

[tobydog]

A ring of soft 'asbestos' rope, if that's what it's still called, will do the trick with some longer screws loosely tightened. Fire cement is a bit restrictive and is probably the reason why the plate cracked as it was held too firmly in place.

Thanks Doug. I'll try and get some. I agree with your reasoning. The body of the burner was contracting at a different rate to that of the lid and hence the crack.

 

[DJH]

Yep. That's right Penners and a bright fire is the answer to keeping the glass reasonably clean....it's nice to end the year agreeing with you.

By the way the pussy wussies wish you all a happy new year... :lol:



Doug

 

[Flyfisher]

A ring of soft 'asbestos' rope, if that's what it's still called, will do the trick with some longer screws loosely tightened. Fire cement is a bit restrictive and is probably the reason why the plate cracked as it was held too firmly in place.

Our stove was fitted with the flue at the rear, so the top vent was sealed with a blanking plate. As well as the modern version of the 'asbestos rope' (the same as used to seal the door), the installer used a flexible 'silicone' like sealer.

A quick search found this: www.stoveseal.com but there are loads of other sites if you search for 'stove sealer'

I don't know for sure but I'd guess that these sorts of jobs should be certified or carried out by a HEATAS installer.

 

[tobydog]

FF - I have a feeling you're right about HETAS approved installers doing the work. I did Google a local company but couldn't see any mention about repairs but I'll give them a call. I clearly don't want the risk of any toxic gases leaking into the house even though Ivor's comment about air coming in through the crack rather than gases going out sounds plausable.

 

[88v8]

I think tbh this is a job which even the veriest nincompoop couldn't mess up. Especially give that we're all pretty practical on here. The only problem I'd foresee might be getting the bolts undone if rusty.

http://www.ebay.co.uk/itm/Heat-Proof-Rope-Glue-Seal-Set-for-Multi-Fuel-Woodburning-Stoves-/171187931952?pt=UK_HG_FireplacesMantelpieces_RL&hash=item27db988b30

I would go for the 3mm. Also available from fireplace shops.

If you're worried about fumes, prop your carbon monoxide alarm next to the offending plate, when it melts realise you didn't really need it anyway

Ivor

 

[Penners]

Last year I had to replace the glass in both doors of our woodburner (which was in the house when we moved here). They nuts were so rusted on to the studs that I wrung three of them off, even after copious soaking with easing oil.

You may wish to extend your mortgage in order to buy replacement glass. Each piece in the doors of our stove cost me over £20! :shock:

 

[tobydog]

Okay, I'll try getting the plate off and see what I've got. Whilst I may not have a degree in nincompoopery, I do have problems with things I can't see. Firstly, electrikery, and secondly, fumes. I hear where you're coming from on prices Penners. It does seem that anything to do with log burners or stoves in general (Aga's particularly included) are bloody expensive. We thought about changing the burner to a new one but I'm almost certain that our flue won't pass muster. The chimney sweep says it's okay but a HETAS engineer will probably think otherwise. Add on the £250 a year NFU wants out of us because we're thatched, I do wonder why we bother.

As for the CO monitor (no offense to our CO's out there!), I'd have to buy one before I melted it!