Chimney and fire stuff
Jan 17th 2009, 12:02 pm
#1
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Re: possible to buy coal?
OK, a couple of misconceptions here.
A fuel can only give out so much heat. Correct useage will maximise that. Wood is a fast fuel, coal is a slow fuel. In order to maximise heat output, coal needs to be held up and the ash allowed to fall away. Failure to do this makes the coal burn slower, and the bars to burn out. Wood is a fast fuel, and if held up on bars, with the ash falling away, it will burn more to flame, and flames send smost all their heat up the chimney. If you don't believe me, see the difference between holding your fingers to the side of a candle flame, or above it. Wood needs to burn more smothered in its ash in order to give out more heat. In an open fire, radiant heat is effectively all the heat you get from the fuel, and you get that more from coal and embers. Flames may look pretty but are very extravagent. If the grate has a lot of bars between you and the coals, then again, that will reduce heat output.
Mixing wood and coal risks you getting the worst of both worlds, as the wood will be more likely to burn to give flames, and the coal will be smothered by the wood ash.
If you cannot get a good fire from wood, trust me you are doing something very, very wrong. Damp fuel is one of the commonest reasons. A damp log can hold a lot of water, and a lot of the energy from the other logs will go towards driving all that water out, which reduces the heat available to warm the room. Remember that that water has to undergo a phase change which is horrendously expensive wrto energy.
A phase change is when water changes from ice to liquid, or from liquid to steam. Consider this. Put a cupful of water into a saucepan, bring it to the boil and time how long that takes. Now without altering the flame, leave it until all that water has boiled away and see how long that takes. That will give you an idea how expensive a phase change is, and, since a damp log can easily hold a cupful of water, how much energy is wasted through burning damp fuel.
This is why steam scalds so badly, and is so dangerous. When the steam hits your skin, it starts to cool, phase changes downwards and dumps its high heat content into your skin.
As for coke burning out a flue. It has little to do with heat, and more to do with acid. All fuels burnt put a lot of acids up your chimney. Carbonic, sulphuric, sulphurous, nitrous and nitric acids, plus a few halide based acids.
The sulphur based acids are far higher in so called smokeless fuels, and the nitrogen based acids increase with fire temperatures.
So, burning coke and other smokeless fuels will result in a higher risk of acid corrosion in metal chimneys. The heat damage is usually caused by a buildup of soot and tars from burning wood and or house coal, which is why regular sweeping is important. A chimney fire can do spectacular structural damage to masonry chimneys as they can burn at temperatures far exceeding that of the fire in the hearth, and it can also accelerate corrosion damage in metal chimneys/flues.
Anyway, hope that helps.
A fuel can only give out so much heat. Correct useage will maximise that. Wood is a fast fuel, coal is a slow fuel. In order to maximise heat output, coal needs to be held up and the ash allowed to fall away. Failure to do this makes the coal burn slower, and the bars to burn out. Wood is a fast fuel, and if held up on bars, with the ash falling away, it will burn more to flame, and flames send smost all their heat up the chimney. If you don't believe me, see the difference between holding your fingers to the side of a candle flame, or above it. Wood needs to burn more smothered in its ash in order to give out more heat. In an open fire, radiant heat is effectively all the heat you get from the fuel, and you get that more from coal and embers. Flames may look pretty but are very extravagent. If the grate has a lot of bars between you and the coals, then again, that will reduce heat output.
Mixing wood and coal risks you getting the worst of both worlds, as the wood will be more likely to burn to give flames, and the coal will be smothered by the wood ash.
If you cannot get a good fire from wood, trust me you are doing something very, very wrong. Damp fuel is one of the commonest reasons. A damp log can hold a lot of water, and a lot of the energy from the other logs will go towards driving all that water out, which reduces the heat available to warm the room. Remember that that water has to undergo a phase change which is horrendously expensive wrto energy.
A phase change is when water changes from ice to liquid, or from liquid to steam. Consider this. Put a cupful of water into a saucepan, bring it to the boil and time how long that takes. Now without altering the flame, leave it until all that water has boiled away and see how long that takes. That will give you an idea how expensive a phase change is, and, since a damp log can easily hold a cupful of water, how much energy is wasted through burning damp fuel.
This is why steam scalds so badly, and is so dangerous. When the steam hits your skin, it starts to cool, phase changes downwards and dumps its high heat content into your skin.
As for coke burning out a flue. It has little to do with heat, and more to do with acid. All fuels burnt put a lot of acids up your chimney. Carbonic, sulphuric, sulphurous, nitrous and nitric acids, plus a few halide based acids.
The sulphur based acids are far higher in so called smokeless fuels, and the nitrogen based acids increase with fire temperatures.
So, burning coke and other smokeless fuels will result in a higher risk of acid corrosion in metal chimneys. The heat damage is usually caused by a buildup of soot and tars from burning wood and or house coal, which is why regular sweeping is important. A chimney fire can do spectacular structural damage to masonry chimneys as they can burn at temperatures far exceeding that of the fire in the hearth, and it can also accelerate corrosion damage in metal chimneys/flues.
Anyway, hope that helps.
Last edited by Sue; Jan 20th 2009 at 12:15 am. Reason: Copied over from another thread
Jan 17th 2009, 12:05 pm
#2
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Chimney and fire stuff
I thought I'd post this response up here in a seperate thread as it struck me it might be useful.
I've been in this field for 30 years now and have a reasonable store of info on the subject. Should anyone want any questions answered, feel free to post them here and I'll do my best to answer them.
A fuel can only give out so much heat. Correct useage will maximise that. Wood is a fast fuel, coal is a slow fuel. In order to maximise heat output, coal needs to be held up and the ash allowed to fall away. Failure to do this makes the coal burn slower, and the bars to burn out. Wood is a fast fuel, and if held up on bars, with the ash falling away, it will burn more to flame, and flames send smost all their heat up the chimney. If you don't believe me, see the difference between holding your fingers to the side of a candle flame, or above it. Wood needs to burn more smothered in its ash in order to give out more heat. In an open fire, radiant heat is effectively all the heat you get from the fuel, and you get that more from coal and embers. Flames may look pretty but are very extravagent. If the grate has a lot of bars between you and the coals, then again, that will reduce heat output.
Mixing wood and coal risks you getting the worst of both worlds, as the wood will be more likely to burn to give flames, and the coal will be smothered by the wood ash.
If you cannot get a good fire from wood, trust me you are doing something very, very wrong. Damp fuel is one of the commonest reasons. A damp log can hold a lot of water, and a lot of the energy from the other logs will go towards driving all that water out, which reduces the heat available to warm the room. Remember that that water has to undergo a phase change which is horrendously expensive wrto energy.
A phase change is when water changes from ice to liquid, or from liquid to steam. Consider this. Put a cupful of water into a saucepan, bring it to the boil and time how long that takes. Now without altering the flame, leave it until all that water has boiled away and see how long that takes. That will give you an idea how expensive a phase change is, and, since a damp log can easily hold a cupful of water, how much energy is wasted through burning damp fuel.
This is why steam scalds so badly, and is so dangerous. When the steam hits your skin, it starts to cool, phase changes downwards and dumps its high heat content into your skin.
As for coke burning out a flue. It has little to do with heat, and more to do with acid. All fuels burnt put a lot of acids up your chimney. Carbonic, sulphuric, sulphurous, nitrous and nitric acids, plus a few halide based acids.
The sulphur based acids are far higher in so called smokeless fuels, and the nitrogen based acids increase with fire temperatures.
So, burning coke and other smokeless fuels will result in a higher risk of acid corrosion in metal chimneys. The heat damage is usually caused by a buildup of soot and tars from burning wood and or house coal, which is why regular sweeping is important. A chimney fire can do spectacular structural damage to masonry chimneys as they can burn at temperatures far exceeding that of the fire in the hearth, and it can also accelerate corrosion damage in metal chimneys/flues.
Anyway, hope that helps.
I've been in this field for 30 years now and have a reasonable store of info on the subject. Should anyone want any questions answered, feel free to post them here and I'll do my best to answer them.
A fuel can only give out so much heat. Correct useage will maximise that. Wood is a fast fuel, coal is a slow fuel. In order to maximise heat output, coal needs to be held up and the ash allowed to fall away. Failure to do this makes the coal burn slower, and the bars to burn out. Wood is a fast fuel, and if held up on bars, with the ash falling away, it will burn more to flame, and flames send smost all their heat up the chimney. If you don't believe me, see the difference between holding your fingers to the side of a candle flame, or above it. Wood needs to burn more smothered in its ash in order to give out more heat. In an open fire, radiant heat is effectively all the heat you get from the fuel, and you get that more from coal and embers. Flames may look pretty but are very extravagent. If the grate has a lot of bars between you and the coals, then again, that will reduce heat output.
Mixing wood and coal risks you getting the worst of both worlds, as the wood will be more likely to burn to give flames, and the coal will be smothered by the wood ash.
If you cannot get a good fire from wood, trust me you are doing something very, very wrong. Damp fuel is one of the commonest reasons. A damp log can hold a lot of water, and a lot of the energy from the other logs will go towards driving all that water out, which reduces the heat available to warm the room. Remember that that water has to undergo a phase change which is horrendously expensive wrto energy.
A phase change is when water changes from ice to liquid, or from liquid to steam. Consider this. Put a cupful of water into a saucepan, bring it to the boil and time how long that takes. Now without altering the flame, leave it until all that water has boiled away and see how long that takes. That will give you an idea how expensive a phase change is, and, since a damp log can easily hold a cupful of water, how much energy is wasted through burning damp fuel.
This is why steam scalds so badly, and is so dangerous. When the steam hits your skin, it starts to cool, phase changes downwards and dumps its high heat content into your skin.
As for coke burning out a flue. It has little to do with heat, and more to do with acid. All fuels burnt put a lot of acids up your chimney. Carbonic, sulphuric, sulphurous, nitrous and nitric acids, plus a few halide based acids.
The sulphur based acids are far higher in so called smokeless fuels, and the nitrogen based acids increase with fire temperatures.
So, burning coke and other smokeless fuels will result in a higher risk of acid corrosion in metal chimneys. The heat damage is usually caused by a buildup of soot and tars from burning wood and or house coal, which is why regular sweeping is important. A chimney fire can do spectacular structural damage to masonry chimneys as they can burn at temperatures far exceeding that of the fire in the hearth, and it can also accelerate corrosion damage in metal chimneys/flues.
Anyway, hope that helps.
Jan 17th 2009, 12:29 pm
#3
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Joined: Feb 2008
Location: Vejer de la Fra., Cadiz
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Re: Chimney and fire stuff
OK, a bit more from another thread.
OK, some very dangerous misconceptions here.
Carbon monoxide from smokeless is far more dangerous, because it carries no warning smoke. Smokeless produces just as much monoxide as anything else.
Green plastic scrubbies will scratch stainless steel, so I can assure you they will scratch glass, even if you don't notice it. Ash too is an abrasive material, so don't use it. Even fine scratches will result in the tar sticking worse in the future.
Only clean the glass in the approved way with the proper cleaning techniques.
If the inside of the stove is getting tarry, and smoke billows out into the room when you open the door, this is quite possibly the result of the flue being partly or completely blocked. Do check it, it could save your life.
All joints need to be constructed so that the male drops down into the female, and I have never in 30 years seen one of those leak condensate where they are the right way up. Get those joints wrong and no sealant will fix it. Metal tubes passing thru a wall mst be surrounded by flexible fireproof materials, if they are cemented in, they will all too often split the cement, and cause radiating cracks all the way round. A length of single skin metal flue inside is a great way to maximise heat transfer to the living space, but it does lead to higher soot and tar deposits, so the flue will need cleaning more frequently. Chimney fires are not safe or clever and do real damage.
Joints between fluepipes when correctly installed need no sealing, a friction fit is perfectly adequate. If any joint or portion leaks smoke/fumes, then there is a fault above that point which needs urgent attention. Any hole/gap in the flue should at all times see air from the room going into the flue, never the other way. A small amount of air entering the flue like this is unimportant, too much can result in chilling of the flue gasses.
If the flue gasses are chilled too much, whether by ingress of air, excessive runs of single skin pipe, or from a metal flue outside being chilled by the wind, then the flue gas temp may drop below the dew point, and condensation will then take place. This can result in black, acidic, tarry water running down the flue in considerable quantities, and where this hits an incorrect joint, leakage and staining will result.
A butterfly damper in the pipe where it exits the stove is usually an indicator of poor quality. It usually means that the seals around the door and the air intakes are less than adequate. Check always that the throat plate can be removed for cleaning. That's often a danger point.
OK, some very dangerous misconceptions here.
Carbon monoxide from smokeless is far more dangerous, because it carries no warning smoke. Smokeless produces just as much monoxide as anything else.
Green plastic scrubbies will scratch stainless steel, so I can assure you they will scratch glass, even if you don't notice it. Ash too is an abrasive material, so don't use it. Even fine scratches will result in the tar sticking worse in the future.
Only clean the glass in the approved way with the proper cleaning techniques.
If the inside of the stove is getting tarry, and smoke billows out into the room when you open the door, this is quite possibly the result of the flue being partly or completely blocked. Do check it, it could save your life.
All joints need to be constructed so that the male drops down into the female, and I have never in 30 years seen one of those leak condensate where they are the right way up. Get those joints wrong and no sealant will fix it. Metal tubes passing thru a wall mst be surrounded by flexible fireproof materials, if they are cemented in, they will all too often split the cement, and cause radiating cracks all the way round. A length of single skin metal flue inside is a great way to maximise heat transfer to the living space, but it does lead to higher soot and tar deposits, so the flue will need cleaning more frequently. Chimney fires are not safe or clever and do real damage.
Joints between fluepipes when correctly installed need no sealing, a friction fit is perfectly adequate. If any joint or portion leaks smoke/fumes, then there is a fault above that point which needs urgent attention. Any hole/gap in the flue should at all times see air from the room going into the flue, never the other way. A small amount of air entering the flue like this is unimportant, too much can result in chilling of the flue gasses.
If the flue gasses are chilled too much, whether by ingress of air, excessive runs of single skin pipe, or from a metal flue outside being chilled by the wind, then the flue gas temp may drop below the dew point, and condensation will then take place. This can result in black, acidic, tarry water running down the flue in considerable quantities, and where this hits an incorrect joint, leakage and staining will result.
A butterfly damper in the pipe where it exits the stove is usually an indicator of poor quality. It usually means that the seals around the door and the air intakes are less than adequate. Check always that the throat plate can be removed for cleaning. That's often a danger point.
Jan 17th 2009, 1:07 pm
#4
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Joined: Oct 2008
Location: near Colmenar, Prov de Malaga
Posts: 5,174
Re: Chimney and fire stuff
Thanks for this bil, hopefully others like me will be grateful for such a stash of knowledge in one fell swoop.
For my own part, I've never quite understood why in our living room fire doesn't really do the job. Room is approx 7m x 4+ m, double wood front door (usual not very good Spanish fit), two door arch openings with curtains, not doors, internal window gap (no window) between it and another room but the killer factors as I see it are that the ceiling slopes from maybe 8ft at one side of the room to about 4m the other ... and the fire is a built in, fan* assisted one in a presumably concrete corner construction. *The fan long ago died because the switch (Spanish of course) was plastic
.
However hard I have it blazing the room never warms above 20 and that's if it's 6 or 7 outside & blazing the entire day!!!!
I'm thinking it's the position of the fire in the corner of a large room..... is it that simple, or would a freestanding cast iron wood burner with a metal flue actually pump out more heat? The concrete 'casing' & mantel does of course to some extent act as a storage heater....
Happy days!
For my own part, I've never quite understood why in our living room fire doesn't really do the job. Room is approx 7m x 4+ m, double wood front door (usual not very good Spanish fit), two door arch openings with curtains, not doors, internal window gap (no window) between it and another room but the killer factors as I see it are that the ceiling slopes from maybe 8ft at one side of the room to about 4m the other ... and the fire is a built in, fan* assisted one in a presumably concrete corner construction. *The fan long ago died because the switch (Spanish of course) was plastic
. However hard I have it blazing the room never warms above 20 and that's if it's 6 or 7 outside & blazing the entire day!!!!
I'm thinking it's the position of the fire in the corner of a large room..... is it that simple, or would a freestanding cast iron wood burner with a metal flue actually pump out more heat? The concrete 'casing' & mantel does of course to some extent act as a storage heater....
Happy days!
Jan 17th 2009, 1:22 pm
#5
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Re: Chimney and fire stuff
That pretty much sums it up, to be honest. A curtain, especially if it is of dense material and not quick to move with air currents, is almost as good as a door for stopping heat transfer. We have one blocking off a large archway into the rest of the house, and the temp drop as you go thru is enormous.
An insert/casette stove is never going to be as good as a freestanding, goes without saying, even with the storage heat effect. I don't know the inner workings of this type, but if the transfer of heat the fan supplies won't work without the fan on, then that's a piece of bad design IMO. In the UK we have Jetmasters which have a very good, non fan way of taking the heat that would be lost to the surrounding stonework, and throwing it into the room. Still not as effective as a freestanding, but a huge improvement.
The other points you identify are also contributary. Stand on a step ladder and feel how warm the air is at the ceiling's highest point. Being in the corner isn't a major point. The single most important question is, how many BTUs does the stove kick out, and how many does the room actually need?
The 'worse' the room is, (ie at retaining and circulating heat/warm air) then the bigger the stove needs to be.
An insert/casette stove is never going to be as good as a freestanding, goes without saying, even with the storage heat effect. I don't know the inner workings of this type, but if the transfer of heat the fan supplies won't work without the fan on, then that's a piece of bad design IMO. In the UK we have Jetmasters which have a very good, non fan way of taking the heat that would be lost to the surrounding stonework, and throwing it into the room. Still not as effective as a freestanding, but a huge improvement.
The other points you identify are also contributary. Stand on a step ladder and feel how warm the air is at the ceiling's highest point. Being in the corner isn't a major point. The single most important question is, how many BTUs does the stove kick out, and how many does the room actually need?
The 'worse' the room is, (ie at retaining and circulating heat/warm air) then the bigger the stove needs to be.
Jan 17th 2009, 2:50 pm
#6
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Re: Chimney and fire stuff
Not really. I enjoy being able to pass on useful stuff, and there is always the chance that someone will add something that I didn't know, or do something that will improve my knowledge base.
In my work, which requires good understanding of chimneys, fires and their functions, I take a malicious pleasure in solving problems that no-one else seems to be able to.
A very useful vice/pet love, in my opinion..... I'd challenge you to sort stuff like the chimney of our house in Suffolk, though: straightforward bungalow, late 60s, straightforward chimney you'd think, yet there was a kink & it trapped tar like nobody's business & by the second chimney fire (- the first was during a dinner party causing much ribaldry for the fire brigade -) they said 'hello, you again...'
......by the third, I'd figured out how to get the ladder & hose up sufficiently swiftly, shin up the roof & deal with it myself quite safely. We moved within a year
Actually, back to the plot I wish there were a freestanding Jotul/FrancoBelge/Villager/Hunter type fire available in Spain with a back boiler
In my work, which requires good understanding of chimneys, fires and their functions, I take a malicious pleasure in solving problems that no-one else seems to be able to.
A very useful vice/pet love, in my opinion..... I'd challenge you to sort stuff like the chimney of our house in Suffolk, though: straightforward bungalow, late 60s, straightforward chimney you'd think, yet there was a kink & it trapped tar like nobody's business & by the second chimney fire (- the first was during a dinner party causing much ribaldry for the fire brigade -) they said 'hello, you again...'
......by the third, I'd figured out how to get the ladder & hose up sufficiently swiftly, shin up the roof & deal with it myself quite safely. We moved within a year
Actually, back to the plot I wish there were a freestanding Jotul/FrancoBelge/Villager/Hunter type fire available in Spain with a back boiler
Jan 17th 2009, 3:31 pm
#7
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Joined: Nov 2003
Location: Chiclana
Posts: 3,327
Re: Chimney and fire stuff
OK, a bit more from another thread.
OK, some very dangerous misconceptions here.
Carbon monoxide from smokeless is far more dangerous, because it carries no warning smoke. Smokeless produces just as much monoxide as anything else.
Green plastic scrubbies will scratch stainless steel, so I can assure you they will scratch glass, even if you don't notice it. Ash too is an abrasive material, so don't use it. Even fine scratches will result in the tar sticking worse in the future.
Only clean the glass in the approved way with the proper cleaning techniques.
If the inside of the stove is getting tarry, and smoke billows out into the room when you open the door, this is quite possibly the result of the flue being partly or completely blocked. Do check it, it could save your life.
All joints need to be constructed so that the male drops down into the female, and I have never in 30 years seen one of those leak condensate where they are the right way up. Get those joints wrong and no sealant will fix it. Metal tubes passing thru a wall mst be surrounded by flexible fireproof materials, if they are cemented in, they will all too often split the cement, and cause radiating cracks all the way round. A length of single skin metal flue inside is a great way to maximise heat transfer to the living space, but it does lead to higher soot and tar deposits, so the flue will need cleaning more frequently. Chimney fires are not safe or clever and do real damage.
Joints between fluepipes when correctly installed need no sealing, a friction fit is perfectly adequate. If any joint or portion leaks smoke/fumes, then there is a fault above that point which needs urgent attention. Any hole/gap in the flue should at all times see air from the room going into the flue, never the other way. A small amount of air entering the flue like this is unimportant, too much can result in chilling of the flue gasses.
If the flue gasses are chilled too much, whether by ingress of air, excessive runs of single skin pipe, or from a metal flue outside being chilled by the wind, then the flue gas temp may drop below the dew point, and condensation will then take place. This can result in black, acidic, tarry water running down the flue in considerable quantities, and where this hits an incorrect joint, leakage and staining will result.
A butterfly damper in the pipe where it exits the stove is usually an indicator of poor quality. It usually means that the seals around the door and the air intakes are less than adequate. Check always that the throat plate can be removed for cleaning. That's often a danger point.
OK, some very dangerous misconceptions here.
Carbon monoxide from smokeless is far more dangerous, because it carries no warning smoke. Smokeless produces just as much monoxide as anything else.
Green plastic scrubbies will scratch stainless steel, so I can assure you they will scratch glass, even if you don't notice it. Ash too is an abrasive material, so don't use it. Even fine scratches will result in the tar sticking worse in the future.
Only clean the glass in the approved way with the proper cleaning techniques.
If the inside of the stove is getting tarry, and smoke billows out into the room when you open the door, this is quite possibly the result of the flue being partly or completely blocked. Do check it, it could save your life.
All joints need to be constructed so that the male drops down into the female, and I have never in 30 years seen one of those leak condensate where they are the right way up. Get those joints wrong and no sealant will fix it. Metal tubes passing thru a wall mst be surrounded by flexible fireproof materials, if they are cemented in, they will all too often split the cement, and cause radiating cracks all the way round. A length of single skin metal flue inside is a great way to maximise heat transfer to the living space, but it does lead to higher soot and tar deposits, so the flue will need cleaning more frequently. Chimney fires are not safe or clever and do real damage.
Joints between fluepipes when correctly installed need no sealing, a friction fit is perfectly adequate. If any joint or portion leaks smoke/fumes, then there is a fault above that point which needs urgent attention. Any hole/gap in the flue should at all times see air from the room going into the flue, never the other way. A small amount of air entering the flue like this is unimportant, too much can result in chilling of the flue gasses.
If the flue gasses are chilled too much, whether by ingress of air, excessive runs of single skin pipe, or from a metal flue outside being chilled by the wind, then the flue gas temp may drop below the dew point, and condensation will then take place. This can result in black, acidic, tarry water running down the flue in considerable quantities, and where this hits an incorrect joint, leakage and staining will result.
A butterfly damper in the pipe where it exits the stove is usually an indicator of poor quality. It usually means that the seals around the door and the air intakes are less than adequate. Check always that the throat plate can be removed for cleaning. That's often a danger point.
Jan 17th 2009, 3:43 pm
#8
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Re: Chimney and fire stuff
Jan 17th 2009, 3:48 pm
#9
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Re: Chimney and fire stuff
Not really. I enjoy being able to pass on useful stuff, and there is always the chance that someone will add something that I didn't know, or do something that will improve my knowledge base.
In my work, which requires good understanding of chimneys, fires and their functions, I take a malicious pleasure in solving problems that no-one else seems to be able to.
A very useful vice/pet love, in my opinion..... I'd challenge you to sort stuff like the chimney of our house in Suffolk, though: straightforward bungalow, late 60s, straightforward chimney you'd think, yet there was a kink & it trapped tar like nobody's business & by the second chimney fire (- the first was during a dinner party causing much ribaldry for the fire brigade -) they said 'hello, you again...'
......by the third, I'd figured out how to get the ladder & hose up sufficiently swiftly, shin up the roof & deal with it myself quite safely. We moved within a year
Actually, back to the plot I wish there were a freestanding Jotul/FrancoBelge/Villager/Hunter type fire available in Spain with a back boiler
In my work, which requires good understanding of chimneys, fires and their functions, I take a malicious pleasure in solving problems that no-one else seems to be able to.
A very useful vice/pet love, in my opinion..... I'd challenge you to sort stuff like the chimney of our house in Suffolk, though: straightforward bungalow, late 60s, straightforward chimney you'd think, yet there was a kink & it trapped tar like nobody's business & by the second chimney fire (- the first was during a dinner party causing much ribaldry for the fire brigade -) they said 'hello, you again...'
......by the third, I'd figured out how to get the ladder & hose up sufficiently swiftly, shin up the roof & deal with it myself quite safely. We moved within a year
Actually, back to the plot I wish there were a freestanding Jotul/FrancoBelge/Villager/Hunter type fire available in Spain with a back boiler
OK, so the problem chimney? My advice would have been as follows. Burn smokeless fuel until it has stripped off all the tar, (1 - 2 years should do it), sweep it regularly and frequently, 2 - 3 times a year during that period or more if it starts to smake as the tar begins to foam, then burn a mix of coal and wood, or just coal and sweep 1 to 2 times a year.
Plus shoot the silly sods who designed and built a chimney with a bend.
Jan 17th 2009, 5:09 pm
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Re: Chimney and fire stuff
Bil - thanks
Moderators - could we have this in the free beer thread? Really useful stuff here.
Moderators - could we have this in the free beer thread? Really useful stuff here.
Jan 17th 2009, 5:37 pm
#12
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Joined: Feb 2008
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Posts: 7,653
Re: Chimney and fire stuff
Thank you very much. As I say, any other questions, feel free.
Here's a quick trouble shooting guide for a smoking fireplace/appliance
1. Does it smoke all the time?
If Yes, it is most likely to be one of the following. Chimney or flue totally or partially blocked, fireplace/appliance opening too big for flue, or restricted terminal. This may sound stupid, but check that it actually HAS a chimney/flue. There are a few occasions when I have discovered that's been the problem. Equally, a flue that is too short, below 12 feet, can fail to function.
cures obvious.
2. Smokes some of the time.
a) if it smokes but stops when you open the door or window, there isn't enough ventilation in the room. cure, allow more air into room
b) smokes only when the wind blows.
If the flue terminates too close to the roof, or below the ridge on pitched roofs, then it is too low and needs raising. If it can't be raised, fit a spinning cowl.
if the flue terminates high up and doesn't have anything within 25 metres that is taller, then you most likely need a cowl. Again the spinners are good, but a chinaman's hat is simpler and does much the same. Make sure all such devices are securely fitted to the outside of the stack/flue.
Here's a quick trouble shooting guide for a smoking fireplace/appliance
1. Does it smoke all the time?
If Yes, it is most likely to be one of the following. Chimney or flue totally or partially blocked, fireplace/appliance opening too big for flue, or restricted terminal. This may sound stupid, but check that it actually HAS a chimney/flue. There are a few occasions when I have discovered that's been the problem. Equally, a flue that is too short, below 12 feet, can fail to function.
cures obvious.
2. Smokes some of the time.
a) if it smokes but stops when you open the door or window, there isn't enough ventilation in the room. cure, allow more air into room
b) smokes only when the wind blows.
If the flue terminates too close to the roof, or below the ridge on pitched roofs, then it is too low and needs raising. If it can't be raised, fit a spinning cowl.
if the flue terminates high up and doesn't have anything within 25 metres that is taller, then you most likely need a cowl. Again the spinners are good, but a chinaman's hat is simpler and does much the same. Make sure all such devices are securely fitted to the outside of the stack/flue.
Jan 17th 2009, 6:04 pm
#13
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Joined: Sep 2002
Location: UK & Spain (Cádiz Province)
Posts: 454
Re: Chimney and fire stuff
There are a few different cowls on the market. I have used a chinaman's hat but in an exposed position found that if the rain fell sideways hard enough it would land in the wood burner and then on the floor. Not a pretty sight.
So have fixed a rotating cowl with slots in the round globe that cost around Euros 45. Seems to do the job but then I wondered if cowls are different for wood burners versus other fires ? Will it get very sooted up and need cleaning ?
So have fixed a rotating cowl with slots in the round globe that cost around Euros 45. Seems to do the job but then I wondered if cowls are different for wood burners versus other fires ? Will it get very sooted up and need cleaning ?
Jan 17th 2009, 7:34 pm
#14
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Thread Starter
Joined: Feb 2008
Location: Vejer de la Fra., Cadiz
Posts: 7,653
Re: Chimney and fire stuff
I suppose you could say it's a trade off between stopping the rain, and obstructing the flue gasses. Remember that a good rule of thumb is to double the size of the escape ports. ie if the flue terminates in a T, both side arms must be at least the same bore as the vertical.
There would be nothing to stop you making a chinaman's hat that was more like an umbrella, so it was physically impossible for rain to get in. You could hang a few inches of fly screen chain from the edge of a conventional chinaman's hat. and just thread a wire thru the bottom loop of each chain to hold the chains together.
All terminals like this will collect soot etc. If they are reachable from a flat roof, no problem, but if not, and the flue has to be swept from the bottom, then the structure needs to be fairly solid and well held on so that you can give it a good bang with the brush head to knock off deposits.
I bought a simple one from Brico depot which works fine. I just go up on the (flat) roof, pull it off and push the brush down.
CAUTION do not clean the flue like this if the soot and the brush cannot pass totally and easily into the fire. If there is a bend, and you just push the soot into the bend, you could kill someone.
There would be nothing to stop you making a chinaman's hat that was more like an umbrella, so it was physically impossible for rain to get in. You could hang a few inches of fly screen chain from the edge of a conventional chinaman's hat. and just thread a wire thru the bottom loop of each chain to hold the chains together.
All terminals like this will collect soot etc. If they are reachable from a flat roof, no problem, but if not, and the flue has to be swept from the bottom, then the structure needs to be fairly solid and well held on so that you can give it a good bang with the brush head to knock off deposits.
I bought a simple one from Brico depot which works fine. I just go up on the (flat) roof, pull it off and push the brush down.
CAUTION do not clean the flue like this if the soot and the brush cannot pass totally and easily into the fire. If there is a bend, and you just push the soot into the bend, you could kill someone.
Jan 18th 2009, 1:16 am
#15
Joined: Apr 2008
Posts: 1,433
Re: Chimney and fire stuff
Attend your local Ferretería and buy a white bottle of HG Hagesan....Limpa vidros para recuperadores de calor. It has a picture of a wood burner on the white plastic bottle and comes in 0.5L bottles with spray top. The soot on the glass just melts away and you just wipe with newspaper or kitchen roll. Trust me I have tried them all and this is the best by miles. You will find a display of HG products at the ferretería on their own display shelving, Then just look for the woodburner on the bottle is costs 11 euros a bottle but lasts for ages and saves lots and lots of swearing etc.
Just found their website and product details. scroll down to stove cleaning glass.
http://en.es.hg.eu/wizard-shop/index...nd_other_rooms