Wood burner / flue / water problem

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Derbyshire
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Hi all,

We had a woodburner fitted during the summer, all above board, certificates issued etc Not long afterwards, during heavy rain, water started leaking from the top of the flue where it meets the register plate There is a rope ‘seal’ around the top of the flue. I spoke to the installer who said this was rare but normal and during heavy rain, water will come down the liner and potentially find it’s way through the rope seal.

3 months later and it’s raining outside and we’re having to wipe the flue every few minutes to catch the long, black drips that are running down it.

I've had the fitter back who’s fitted a different cowl which has an extra flat layer that should shed the water better. Needless to say, it doesn’t and rain is still coming in. I also asked him to replace the fire rope around the top of the flue as it had gone black with all the water soaking through it and smelt like 1000 concentrated cigarettes, he applied silicone followed by the fire rope.

We’ve had the fire on for the first time tonight and about an hour in I heard a sizzling noise and water began weeping through the fire rope. Which has again gone black and stinks. Prior to the work being done I had the clay liner inspected which showed it to be in 'excellent condition and very clean'.

Personally, I think something is fundamentally wrong with the install and I’ve lost confidence in the fitter’s ability/desire to solve the problem. The diagram below shows what I mean:


This looks fundamentally flawed to me, there is always going to be a void where water/soot can gather due to the difference in size between the flue and the clay liner.

Can anyone offer advice on whether this is correct?
 
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might be that when fitting the cowl he's cracked the clay liner in the chimney at the roof and water seeping in thru that.
The clay liner may have looking in good working order before fitting but if the clay liner had any water in it. say a hairline crack when you started using the stove the heat may of dried out the liner making the crack bigger. Get the liner chacked again too.
 
I think you will have to have a liner fitted

Definately the best idea based on my experience of water ingress into un-lined chimneys. My wood burner has a twinned wall metal flue to the top ot the stack.

HETAS can provide the best advice and you can check with them if the installer is properly qualified to install wood burners.
 
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This looks fundamentally flawed to me, there is always going to be a void where water/soot can gather due to the difference in size between the flue and the clay liner.

Can anyone offer advice on whether this is correct?
The bottom end of the install that you've shown is irrelevant for your problem. The problem isn't the water pooling, the problem is the volume of water getting down the flue.

Can you take a photo of the top of the chimney so we can see what's going on there.
 
[/ATTACH] 9068027B-9EB4-498D-869B-283CEF13090F.jpeg
Hi all,

We had a woodburner fitted during the summer, all above board, certificates issued etc Not long afterwards, during heavy rain, water started leaking from the top of the flue where it meets the register plate There is a rope ‘seal’ around the top of the flue. I spoke to the installer who said this was rare but normal and during heavy rain, water will come down the liner and potentially find it’s way through the rope seal.

3 months later and it’s raining outside and we’re having to wipe the flue every few minutes to catch the long, black drips that are running down it.

I've had the fitter back who’s fitted a different cowl which has an extra flat layer that should shed the water better. Needless to say, it doesn’t and rain is still coming in. I also asked him to replace the fire rope around the top of the flue as it had gone black with all the water soaking through it and smelt like 1000 concentrated cigarettes, he applied silicone followed by the fire rope.

We’ve had the fire on for the first time tonight and about an hour in I heard a sizzling noise and water began weeping through the fire rope. Which has again gone black and stinks. Prior to the work being done I had the clay liner inspected which showed it to be in 'excellent condition and very clean'.

Personally, I think something is fundamentally wrong with the install and I’ve lost confidence in the fitter’s ability/desire to solve the problem. The diagram below shows what I mean:


This looks fundamentally flawed to me, there is always going to be a void where water/soot can gather due to the difference in size between the flue and the clay liner.

Can anyone offer advice on whether this is correct?



Is your drawing correct, if you have an inspection plate it is to sweep the flue and remove debris so there should be a space between the two sizes of flue.
The masonry length of flue is likely to be cold so condensation can form which runs back down especially if useasoned or damp wood is burnt .
As previously said, if you are getting a serious amount of water then it will be from poorly constructed or damaged masonry/leaking pot.
You should get someone to check if you have the lead tray in the right place and weep holes for chimney water to escape
 
[/ATTACH] View attachment 174839



Is your drawing correct, if you have an inspection plate it is to sweep the flue and remove debris so there should be a space between the two sizes of flue.
The masonry length of flue is likely to be cold so condensation can form which runs back down especially if useasoned or damp wood is burnt .
As previously said, if you are getting a serious amount of water then it will be from poorly constructed or damaged masonry/leaking pot.
You should get someone to check if you have the lead tray in the right place and weep holes for chimney water to escape

Yes, definitely correct, there's no hatch. Either side of the clay liner is brickwork, there's no chimney to sweep, the only thing to sweep is the clay liner and that's done through the stove.
 
The bottom end of the install that you've shown is irrelevant for your problem. The problem isn't the water pooling, the problem is the volume of water getting down the flue.

Can you take a photo of the top of the chimney so we can see what's going on there.

Yes, will get a picture.

I think you're right to a point, however, in mind there shouldn't be any point where material can gather, whether it be: water, soot or tar. I think this is why they say all flue connections should have the socket/male end facing up so that any deposits are passing into the next connection.
 
If the 6” length is free of bends and snots a 5” liner may fit but the stove would need to be 5kw or lower and defra exempt.
If you have 5” into. 6” then how will the top section be swept as a brush that can pass through the smaller section would be too loose in the top. It can be done with power whips which would require a pro though
 
Yes, will get a picture.

I think you're right to a point, however, in mind there shouldn't be any point where material can gather, whether it be: water, soot or tar. I think this is why they say all flue connections should have the socket/male end facing up so that any deposits are passing into the next connection.
I agree, but all that would happen is that the water coming down your flue would end up in the stove. Its the water ingress that you need to fix.
 
A new chimney pot was installed when the stove was fitted, this was the original cowl that was fitted on the chimney pot:


Due to the amount of rain coming in it was swapped to this one last week:


It certainly doesn't look new and I'm not convinced it's fitted properly either.
 

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