Hot chimney breast

harr

Hi
Got an insert stove done before Christmas and I noticed that my chimney breast gets fairly warm and retains the heat even into the next day.
It was installed by a qualified company who have many years experience and done a lot of friends and family stoves..
He checked chimney before installing and said it was ok to use without a flue..
No back boiler or anything and chimney was cleaned before installing.
I don’t have massive fires as it’s fairly warm as is.
My fuel consumption has about halved since I got it...I use a mix of briquettes, stove coal and logs..
Apologies if this has been answered before..

the_pen_turner

is there a question.
sounds like its working perfectly

my3cents

Sounds good to me but you may be building up to a problem you can easily fix.

With no liner your chimney will soot up far quicker than with a liner so if this fire is in regular use you need to sweep it more regularly than normal. The fact the chimney breast is getting warm indicates no liner - no problem - however it also indicates that the small amount of heat that is wasted up the chimney from a stove is warming the bottom of the chimney. Further up it may not be heating it up enough (an open fire wastes a massive amount of heat heating the chimney) so more soot will accumulate than with a stove fire. Hence sweep more often. Best thing to do is a quick up and down with the brushes yourself once a month.

Edit> Sweep after about a month of use or about 30 fires which ever comes first. If you find there is nothing much to clean then push that out to once every 6 weeks and so on until you find the point at which you are doing the minimum sweeping for the maximum effect. If you don't understand whats going on not having a liner isn't that good an idea but regular sweeping will soon get you up to speed with whats going on. If your lucky you will find you only need the recommended 2 sweeps a year, but if not you won't have to worry about a chimney fire (provided you sweep often enough).

harr

my3cents wrote: »

Sounds good to me but you may be building up to a problem you can easily fix.

With no liner your chimney will soot up far quicker than with a liner so if this fire is in regular use you need to sweep it more regularly than normal. The fact the chimney breast is getting warm indicates no liner - no problem - however it also indicates that the small amount of heat that is wasted up the chimney from a stove is warming the bottom of the chimney. Further up it may not be heating it up enough (an open fire wastes a massive amount of heat heating the chimney) so more soot will accumulate than with a stove fire. Hence sweep more often. Best thing to do is a quick up and down with the brushes yourself once a month.

Edit> Sweep after about a month of use or about 30 fires which ever comes first. If you find there is nothing much to clean then push that out to once every 6 weeks and so on until you find the point at which you are doing the minimum sweeping for the maximum effect. If you don't understand whats going on not having a liner isn't that good an idea but regular sweeping will soon get you up to speed with whats going on. If your lucky you will find you only need the recommended 2 sweeps a year, but if not you won't have to worry about a chimney fire (provided you sweep often enough).

Thanks for the explanation and sorry the question should have been if it was normal.
I will get brushes out at weekend and give it a clean.
The wall In bedroom above stove is also warm nothing major but warm enough that we don’t need the rad on.
I take it it’s not a major job to install a flue if it is needed..
I will have a good idea at weekend when I give it a clean as it was only 5 or 6 weeks ago it was done.

my3cents

harr wrote: »

Thanks for the explanation and sorry the question should have been if it was normal.
I will get brushes out at weekend and give it a clean.
The wall In bedroom above stove is also warm nothing major but warm enough that we don’t need the rad on.
I take it it’s not a major job to install a flue if it is needed..
I will have a good idea at weekend when I give it a clean as it was only 5 or 6 weeks ago it was done.

My point is that if you don't have a clue then a liner is essential. If you are practical and understand the reason for a liner and that a cold unlined chimney will get sooted up more quickly than a lined one then you you can sweep a little more often and not worry about a liner.

There is another thing to be aware of and that is with the adapter used to connect into the chimney its possible for soot to build up around it plus soot may if allowed to build up in the chimney start dropping down and build up blocking the chimney. Knowing these things can happen should mean you can check occasionally and be safe from the possible problems.

The issue arises with people who just don't check anything and burn away in ignorance.

Cerco

If the stove was only installed before Christmas then I cannot imagine a need to sweep the chimney at this early stage. You state that chimney was cleaned before installation and the installers were experienced.
I would raise the issue with them in the first instance and await their response.

my3cents

Cerco wrote: »

If the stove was only installed before Christmas then I cannot imagine a need to sweep the chimney at this early stage. You state that chimney was cleaned before installation and the installers were experienced.
I would raise the issue with them in the first instance and await their response.

Your imagination could easily get you into trouble. Its really not ideal to fit a stove directly to an existing chimney. There are varying degrees of how bad it can be which vary on how the stove is used. A worst case scenario would banking a stove up and keeping it going overnight and then letting the chimney go cold again before relighting the stove. Best case would be that the stove is run very hot. Then it depends on the chimney a chimney in an internal wall will be better than on an outside wall facing the prevailing wind.

An unlined chimney is designed for an open fire that wastes 60-70% of the heat up the chimney. An unlined chimney needs that heat to keep the flue gases hot enough to exit the chimney quickly and to take most of the soot and tar with it. Attach a stove to an unlined chimney and the heat that went up the chimney and kept it free of soot and tar drops by at least 50% as the stove only wastes about 25% of the heat up the chimney. Your unlined chimney now stays cold and will now not get hot enough to stop the tar and soot condensing on the walls of the chimney. Hence no liner with a stove means the chimney needs sweeping more often.

There can be additional issues due to the fact this extra tar and soot drops back down the chimney but in most cases some extra sweeping prevents them.

If the OP is lucky he'll sweep the chimney now and curse me for wasting his time on the other hand he may clean out far more than he expected. Either way he can then make a decision based on his usage patterns and prevailing conditions on how often he needs to sweep his chimney.

Cerco

my3cents wrote: »

Your imagination could easily get you into trouble. Its really not ideal to fit a stove directly to an existing chimney. There are varying degrees of how bad it can be which vary on how the stove is used. A worst case scenario would banking a stove up and keeping it going overnight and then letting the chimney go cold again before relighting the stove. Best case would be that the stove is run very hot. Then it depends on the chimney a chimney in an internal wall will be better than on an outside wall facing the prevailing wind.

An unlined chimney is designed for an open fire that wastes 60-70% of the heat up the chimney. An unlined chimney needs that heat to keep the flue gases hot enough to exit the chimney quickly and to take most of the soot and tar with it. Attach a stove to an unlined chimney and the heat that went up the chimney and kept it free of soot and tar drops by at least 50% as the stove only wastes about 25% of the heat up the chimney. Your unlined chimney now stays cold and will now not get hot enough to stop the tar and soot condensing on the walls of the chimney. Hence no liner with a stove means the chimney needs sweeping more often.

There can be additional issues due to the fact this extra tar and soot drops back down the chimney but in most cases some extra sweeping prevents them.

If the OP is lucky he'll sweep the chimney now and curse me for wasting his time on the other hand he may clean out far more than he expected. Either way he can then make a decision based on his usage patterns and prevailing conditions on how often he needs to sweep his chimney.

No trouble for me to imagine. I did not advocate not using a flue.
The person who installed it decided it was not required. As it seems he is a professional and inspected the chimney then the issue should be raised with him.

Either way I cannot see how a chimney requires re sweeping after a couple of weeks.

gillad

Cerco wrote: »

The person who installed it decided it was not required. As it seems he is a professional and inspected the chimney then the issue should be raised with him.
.

A Person that fits a stove without the proper 5 or 6 inch flue is not a professional.
Fire safety an Draw are the factors that are overlooked here, which can cause problems.

harr

gillad wrote: »

A Person that fits a stove without the proper 5 or 6 inch flue is not a professional.
Fire safety an Draw are the factors that are overlooked here, which can cause problems.

That small bit of flue is in place what I was wondering was if it needed a flue up full length of the chimney...

divillybit

When I bought my house 2 years ago (a new build detatched house in an estate) I was getting a Stanley backboiler stove put in. The builder said that a metal flexible pipe had to be used inside the chimney flue with the stove, as he said he wouldnt be held responsible if one of the flue liners cracked from the heat the stove put out.

My neighbours who bought the same sized detatched house and got the exact same stove fitted but didnt get the flexible pipe fitted had to call the fire brigade out twice last year where the chimney went on fire.. They regret not getting the flue liner pipe fitted when the stove was being fitted. But I think they were burning alot of damp turf and other rubbish too which would definitely cause soot to build up quicker. The pipe runs all the way from the stove to the chimney cap.

gillad

harr wrote: »

That small bit of flue is in place what I was wondering was if it needed a flue up full length of the chimney...

Yes,the flexi flue must go the full length of the chimney for it to be considered safe.

Your chimney breast is hot because heat is going up the chimney and coming out through the wall and this may be due to too much draw up the chimney because the chimney opening is 8 inches wide instead of the recommended 5 or 6 inches.

ted1

divillybit wrote: »

When I bought my house 2 years ago (a new build detatched house in an estate) I was getting a Stanley backboiler stove put in. The builder said that a metal flexible pipe had to be used inside the chimney flue with the stove, as he said he wouldnt be held responsible if one of the flue liners cracked from the heat the stove put out.
.

Asfaik their is a relative short life span on those flexible tubes.

Make sure to get a CO alarm in each room the chimney passes through

my3cents

gillad wrote: »

Yes,the flexi flue must go the full length of the chimney for it to be considered safe.

Your chimney breast is hot because heat is going up the chimney and coming out through the wall and this may be due to too much draw up the chimney because the chimney opening is 8 inches wide instead of the recommended 5 or 6 inches.

Then you just close the stove down, the stove also gets too hot in those conditions and the OP hasn't reported that as a problem. While flue sizing is often ignored I don't think its a major issue here.

There can however be some major issues with some of the connectors used between the stove and the chimney or if just a short length of liner is used to connect the stove into the chimney. What can happen is that the soot and tar that drops down the chimney (including when swept) can get caught between the chimney and the outside of the connector. This is the hottest part of the chimney so tar can melt and drop down around the outside of the connector. Apart from the potential mess there is also a potential to greatly increase the chance of a chimney fire.

Obviously I've no idea how the OP's stove is connected but if its just a short length of liner that isn't sealed at the top to stop tar collecting at the back of it then its likely to be a problem unless its removed regularly and cleaned around.

harr

Hard to describe...he put in a plate with a hole in it and the small bit of flue was sealed then that extended a small bit up chimney.
And no the stove itself isn’t getting red hot or anything great heat from it , the marble surround would also get Fairly hot..
Might just just give him a buzz to have a look incase anything wrong, he said he was going to ring anyway to make sure all was in order...
Will be cleaning chimney at weekend so that should tell a lot...

my3cents

harr wrote: »

Hard to describe...he put in a plate with a hole in it and the small bit of flue was sealed then that extended a small bit up chimney.
And no the stove itself isn’t getting red hot or anything great heat from it , the marble surround would also get Fairly hot..
Might just just give him a buzz to have a look incase anything wrong, he said he was going to ring anyway to make sure all was in order...
Will be cleaning chimney at weekend so that should tell a lot...

Make a point of asking if there is enough of a gap anywhere for the adapter pipe to collect tar were it can't cleaned by sweeping between the adapter pipe and the chimney.