Why wont my chimney draw properly?
Discussion
I recently removed the old nasty gas fire that was in situ when we bought the house. This left a nice open fireplace that we had planned to put a wood burner in. Due to the angle of the existing clay chimney liner however that doesn't look like being possible. While we work out what to do I thought I'd just use the old basket we bought from the last house to have some 'normal' fires. I'm not having any luck getting the smoke to go up the chimney though but am being particularly successful at filling the lounge with smoke.
Does anyone know what the problem may be? The fireplace is pretty tall compared to the basket and was swept after I removed all the backfill for the gas fire. The pot on top was changed from a gas one to a bird guard too.
On the terrible picture I've attached, the yellow lines are the approximate position of the clay liner, it then goes vertical around the edge of the image, the red is roughly what the fireplace does behind the brick.
Does anyone have any tricks for starting to get the chimney to draw?
I was wondering if installing a piece of fireboard inside the top of the fireplace to funnel the smoke up to the clay lining would help at all?
Does anyone know what the problem may be? The fireplace is pretty tall compared to the basket and was swept after I removed all the backfill for the gas fire. The pot on top was changed from a gas one to a bird guard too.
On the terrible picture I've attached, the yellow lines are the approximate position of the clay liner, it then goes vertical around the edge of the image, the red is roughly what the fireplace does behind the brick.
Does anyone have any tricks for starting to get the chimney to draw?
I was wondering if installing a piece of fireboard inside the top of the fireplace to funnel the smoke up to the clay lining would help at all?
I know the yellow lines are 'approximate', but would you say the actual angle of the flue is at 45 degrees or greater.
I only ask, as less than 45 degrees and it's never going to work properly.
What is the ventilation into the room like?
You are only going to get a good draw if the ventilation is equal to, or greater than, the natural draw of the flue, otherwise you'd be creating a vacuum!
I only ask, as less than 45 degrees and it's never going to work properly.
What is the ventilation into the room like?
You are only going to get a good draw if the ventilation is equal to, or greater than, the natural draw of the flue, otherwise you'd be creating a vacuum!
I had the same problem,
Same kinda bend and clay lining etc...
It was all down to the pot on top of the chimney. Try it without one I get the odd drop of rain very very rarely and thats about it. Otherwise it made all the difference works a treat now..
Oh and set the cast grate as far back as possible.
Same kinda bend and clay lining etc...
It was all down to the pot on top of the chimney. Try it without one I get the odd drop of rain very very rarely and thats about it. Otherwise it made all the difference works a treat now..
Oh and set the cast grate as far back as possible.
shakotan said:
I know the yellow lines are 'approximate', but would you say the actual angle of the flue is at 45 degrees or greater.
I only ask, as less than 45 degrees and it's never going to work properly.
What is the ventilation into the room like?
You are only going to get a good draw if the ventilation is equal to, or greater than, the natural draw of the flue, otherwise you'd be creating a vacuum!
Angle of the flue is too shallow I think, it's not 45 degrees anyway.I only ask, as less than 45 degrees and it's never going to work properly.
What is the ventilation into the room like?
You are only going to get a good draw if the ventilation is equal to, or greater than, the natural draw of the flue, otherwise you'd be creating a vacuum!
Ventilation is pretty good, there's a vent in the floor on the right that you can see by the clock. Opening windows/doors didn't make much difference.
Grandad Gaz said:
What size is the existing clay liner? It could be too small.
First thing to try is to open the windows and see if that helps. Second is to temporary fit a board over the top 6" or so of the opening. it could be the opening is to big for the flue.
Liner is 6 or 7 inch I think, not 'small' but not a full size chimney of course. I'll try the board over the opening. I did wonder if it all needs raising up a bit from the floor, it will be when we do it properly but only 2 inches I'd guess. What material should I use? And where would I buy it?First thing to try is to open the windows and see if that helps. Second is to temporary fit a board over the top 6" or so of the opening. it could be the opening is to big for the flue.
David58 said:
I had the same problem,
Same kinda bend and clay lining etc...
It was all down to the pot on top of the chimney. Try it without one I get the odd drop of rain very very rarely and thats about it. Otherwise it made all the difference works a treat now..
Oh and set the cast grate as far back as possible.
We've had a proper bird guard fitted that is basically 4 inches of nothing but wire and then a flat metal 'lid'. Can't imagine that stopping it from drawing, could it?Same kinda bend and clay lining etc...
It was all down to the pot on top of the chimney. Try it without one I get the odd drop of rain very very rarely and thats about it. Otherwise it made all the difference works a treat now..
Oh and set the cast grate as far back as possible.
Agent L said:
Grandad Gaz said:
What size is the existing clay liner? It could be too small.
First thing to try is to open the windows and see if that helps. Second is to temporary fit a board over the top 6" or so of the opening. it could be the opening is to big for the flue.
Liner is 6 or 7 inch I think, not 'small' but not a full size chimney of course. I'll try the board over the opening. I did wonder if it all needs raising up a bit from the floor, it will be when we do it properly but only 2 inches I'd guess. What material should I use? And where would I buy it?First thing to try is to open the windows and see if that helps. Second is to temporary fit a board over the top 6" or so of the opening. it could be the opening is to big for the flue.
If opening a door or window didn't help, then it's the 'outward' travel, rather than 'inward' that's at issue.
You could try throttling back the opening, as suggested above. It may be that too much air is being drawing in and it's 'choking' the liner, with the excess spilling back into the room.
If this doesn't work, then it's time to get someone up onto the roof and start playing about with the termination.
You have checked that the liner is clear along it's full travel, haven't you?
Edited by shakotan on Sunday 21st February 18:38
Thanks for all the advice so far 
The chimney was swept less than a week before I first tried a fire.
We've had two quotes for burner installation, the first involved breaking open the chimney breast to remove a section where the liner rounds the corner. The second said it would be almost impossible and they wouldn't take it on. I'm not keen to break into the chimney breast as that will condemn the chimney for any future use that doesn't involve a steel liner.
The chimney was swept less than a week before I first tried a fire.TooLateForAName said:
If the original chimney opening has been partly blocked for the clay liner to be installed you have no chance (zero, null, none) of getting a decent draw. All you'll do is fill the room with smoke.
Woodburner.
I'm assuming that the house was built with the liner in place. The sweep has done another house in the close and it was the same. There are also signs of a fire being used previous to the gas one being installed so I think it 'should' work. Do you mean blocked as in filled in around the clay liner? That has been done but I think it was done when the house was built.Woodburner.
We've had two quotes for burner installation, the first involved breaking open the chimney breast to remove a section where the liner rounds the corner. The second said it would be almost impossible and they wouldn't take it on. I'm not keen to break into the chimney breast as that will condemn the chimney for any future use that doesn't involve a steel liner.
Edited by Agent L on Sunday 21st February 20:06
Ferg said:
Chimneys always struggle to draw when cold. Try heating it with a blowlamp for a while and try again.
I think I may have to sell 'electric chimney pre-heaters' (like you got on old diesel engines)...I guess that those silver rotating things you see on some chimneys help to turn horizontally passing breezes into an updraught, yes?
TooLateForAName said:
An open fire needs quite a big chimney. If you have a restricted opening (which you have) then you'll not get it to draw.
How big is the flue diameter?
You can put a gather in but tbh if the flue is 5 or 6 inches it wont help. How old is the house?
Flue is 6" at least I think but not bigger than 7". It's in a very hard place to measure. House is mid 60's.How big is the flue diameter?
You can put a gather in but tbh if the flue is 5 or 6 inches it wont help. How old is the house?
I think you'll struggle.
However this is what I would do to test it quickly.
Build a platform with a few loose bricks to lift your firebasket up.
Assuming you dont have a flamethrower to hand, burn some crumpled up newspaper (dry newspaper will burn quickly with a good flame and not lots of smoke) or a firelighter which should get warm air moving up the chimney. Once thats burnt OK, light a small fire using absolutely dry wood. I'd use a few bits of an old pallet - again looking for something that burns fast and clean.
The chimney needs to be able to handle all the smoke that the fire produces, if your fire is too big for the flue then you'll get a room full of smoke. That firebasket looks too big to me for the size of the flue you seem to have. You get away with a flue on a stove because you control the airflow through the stove and everything goes up the chimney, with an open fire you have almost no controland the fire will get more air than the flue can handle. I think that you might get away with a brazier sort of thing, but not with a large firebasket at the bottom of the large opening. One trick I found with one of our chimneys was that it was much easier to get going with the window open - and this in an old house with plenty of 'ventilation'. Once the fire got going the window could be closed. That fire never drew well and in the end I fitted a woodburner.
I'm surprised that you have a clay liner that wont take a woodburner, were these houses all fitted with gas fires when built? Is it problematic to sweep it or is it OK?
However this is what I would do to test it quickly.
Build a platform with a few loose bricks to lift your firebasket up.
Assuming you dont have a flamethrower to hand, burn some crumpled up newspaper (dry newspaper will burn quickly with a good flame and not lots of smoke) or a firelighter which should get warm air moving up the chimney. Once thats burnt OK, light a small fire using absolutely dry wood. I'd use a few bits of an old pallet - again looking for something that burns fast and clean.
The chimney needs to be able to handle all the smoke that the fire produces, if your fire is too big for the flue then you'll get a room full of smoke. That firebasket looks too big to me for the size of the flue you seem to have. You get away with a flue on a stove because you control the airflow through the stove and everything goes up the chimney, with an open fire you have almost no controland the fire will get more air than the flue can handle. I think that you might get away with a brazier sort of thing, but not with a large firebasket at the bottom of the large opening. One trick I found with one of our chimneys was that it was much easier to get going with the window open - and this in an old house with plenty of 'ventilation'. Once the fire got going the window could be closed. That fire never drew well and in the end I fitted a woodburner.
I'm surprised that you have a clay liner that wont take a woodburner, were these houses all fitted with gas fires when built? Is it problematic to sweep it or is it OK?
Cold plugs in the breast itself will stop the smoke drawing your fire.
Easy to clear and get a draw going, roll up a large piece of newspaper (light first, get going) then put "up" the chimney as far as your arm and tongs will allow. As it starts to clear the cold plug you should hear a roar as it takes, slowly pull it down into the casket. Then light your fire with plenty of scrunched up paper and kindling. Only put coals on after the kindling and paper is well lit.
Might be worth sitting your casket on bricks to see if the height of your chamber is too high. If it is, simple procedure is to raise the floor level within the chamber itself (on bricks temporarily to test, then on fire-bricks or proper tiles as a permenant measure) or create a lowered chamber roof (metal workers can fashion these and fit for not much money).
May even work out cheaper to buy a bigger / higher casket in the long run if its a roof height problem.
Easy to clear and get a draw going, roll up a large piece of newspaper (light first, get going) then put "up" the chimney as far as your arm and tongs will allow. As it starts to clear the cold plug you should hear a roar as it takes, slowly pull it down into the casket. Then light your fire with plenty of scrunched up paper and kindling. Only put coals on after the kindling and paper is well lit.
Might be worth sitting your casket on bricks to see if the height of your chamber is too high. If it is, simple procedure is to raise the floor level within the chamber itself (on bricks temporarily to test, then on fire-bricks or proper tiles as a permenant measure) or create a lowered chamber roof (metal workers can fashion these and fit for not much money).
May even work out cheaper to buy a bigger / higher casket in the long run if its a roof height problem.
We always used to start our fires by building up paper, kindling and logs/coal on the grate, lighting the paper in a few places, then putting a mesh fireguard across the open fireplace. We would then put a sheet of newspaper over the fireguard, leaving a gap at the bottom. Natural convection would suck the paper against the fireguard and make a good seal. Then the fire gets a strong blast of air across the bottom, making the paper roar, which only increases the blast. Leave the whole thing until the fire gets into the kindling and you're away.
The paper over the fireguard would usually be fine - the metal pulls away too much heat for there to be any spot burns. Once the fire is really going, it would begin to char a little if left in place.
The point is, you need to 'force' the draw until the fire's going - then the chimney will draw naturally. Just lighting a fire in the grate isn't going to be enough. Don't go sticking lighted paper up the chimney - all sorts of interesting things can happen if you do.
The paper over the fireguard would usually be fine - the metal pulls away too much heat for there to be any spot burns. Once the fire is really going, it would begin to char a little if left in place.
The point is, you need to 'force' the draw until the fire's going - then the chimney will draw naturally. Just lighting a fire in the grate isn't going to be enough. Don't go sticking lighted paper up the chimney - all sorts of interesting things can happen if you do.
Edited by Tuna on Monday 22 February 15:34
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