Woodburner...

[john87]

8 minutes ago, Stubby said:

It lessens the effect of corosive condensation and increases the draw .

Ah, yes, good thinking.. My house no trouble with draw, so i will not bother or need one of them liner things, rather have warm walls!!

[Mick Dempsey]

14 hours ago, Big J said:

This is like a convention of flat earthers. Constantly trying to find legitimacy in a laughable concept. 

 

Justify the open fire which ever way you like - it smells nice, I like the crackles, the missus won't take her clothes off infront of a stove....

 

Just please don't try to make any claims about efficiency being even remotely comparable.

You’re just a shill for Big Woodstove.

 

[Stubby]

36 minutes ago, john87 said:

Ah, yes, good thinking.. My house no trouble with draw, so i will not bother or need one of them liner things, rather have warm walls!!

Mine had ( still has ) a 7.5" clay liner . A 6" SS liner fits snugly up inside it and the stove is attartched to that . When its been on a few hours the chimny breast in the loft gets warm . So no problem heating the wall here either .

[john87]

1 hour ago, Stubby said:

Mine had ( still has ) a 7.5" clay liner . A 6" SS liner fits snugly up inside it and the stove is attartched to that . When its been on a few hours the chimny breast in the loft gets warm . So no problem heating the wall here either .

That is good to know!! I thought the brickwork would stay stoney cold as it were!!

 

john..

[Billhook]

16 minutes ago, john87 said:

That is good to know!! I thought the brickwork would stay stoney cold as it were!!

 

john..

There are occasions particularly on a North facing wall where the chimney has been built on the outside, that it will just not draw very well in cold weather.

This is especially bad when starting and there may be a down draught which fills the room with smoke.  An insulated flue would be the answer in most cases 

[Mick Dempsey]

3 hours ago, Billhook said:

There are occasions particularly on a North facing wall where the chimney has been built on the outside, that it will just not draw very well in cold weather.

This is especially bad when starting and there may be a down draught which fills the room with smoke.  An insulated flue would be the answer in most cases 

That explains an issue I had a few years back. 

[john87]

16 minutes ago, Mick Dempsey said:

That explains an issue I had a few years back. 

The smoke goes up the flue, because it is warmer and thus less dense than the outside air and so it rises [as a hot air balloon would] This is why longer flues draw better, they contain more hot air..

 

Now, say it is warmer outside than it is in your house, the opposite happens and the air outside will come DOWN the flue, and, as you say, fill the room with smoke..

 

john..

[Mick Dempsey]

Just now, john87 said:

The smoke goes up the flue, because it is warmer and thus less dense than the outside air and so it rises [as a hot air balloon would] This is why longer flues draw better, they contain more hot air..

 

Now, say it is warmer outside than it is in your house, the opposite happens and the air outside will come DOWN the flue, and, as you say, fill the room with smoke..

 

john..

Don’t think you’re right, it gets pulled because of the Venturi effect (initially at least)

that’s why when the wind is blowing it pulls better.

[john87]

3 minutes ago, Mick Dempsey said:

Don’t think you’re right, it gets pulled because of the Venturi effect (initially at least)

that’s why when the wind is blowing it pulls better.

Have a read of this..

Why Is My Chimney & Fireplace Drafty? - Certified Chimney Sweeps

WWW.HIGHSCHIMNEY.COM

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Interested in diagnosing a smokey fireplace? Call our chimney experts in the Gaithersburg MD area for a chimney...

 

john..

[openspaceman]

4 hours ago, Stubby said:

Mine had ( still has ) a 7.5" clay liner . A 6" SS liner fits snugly up inside it and the stove is attartched to that . When its been on a few hours the chimny breast in the loft gets warm . So no problem heating the wall here either .

I suppose because it was a snug fit there was no room to pour insulation around the liner and hence the warming of the loft.

 

If you consider what a chimney does, it removes all harmless the products of complete  combustion as well as the toxic  bit from incomplete combustion from the living space and puts them high enough that they will be up and diluted before they reach any neighbours. So logically you don't want any heat going up the chimney. With a gas boiler this is done by transferring any remaining heat from the flue gases to the combustion air and allowing little droplets of water to form. With a log burner there is much more water vapour in the flue gases so they need to be kept warm enough so as not to condense out onto the chimney walls. With our industrial boilers we would extract as much heat from the firebox and send it up the chimney at about 110C, as the chimneys were double insulated  the gases should still have been above 100C at the top. This is one reason why woodburners are never as efficient as natural gas boilers.

 

Now in my case because my stove does not keep burning all night I am happy my stove leaves some excess heat in the flue gases as during the day the chimney breast heats up and then gives up its heat while the fire is out. My 6" flue exhausts into an 8" approx. concrete, cast in situ chimney. Not ideal as this means the flue gases slow down as they pass the register plate. I seldom allow the flue temperature to get above 150C and on a mild day will allow it to drop to around 110.

 

The corollary of this is the batch burning masonry stoves which instead of being regularly loaded with logs during the day are loaded once with a few tens of kg of dry wood and then burned flat out. All the heat is used to heat the masonry surrounds as the flue gases travel through a labyrinth of brickwork. The fire goes out and is sealed and the  brickwork continues to heat the house until the next day when it is reloaded and fired.