Convesa twin wall flue

[JT19]

9 hours ago, slim reaper said:

So you only have two locking bands on the whole flue?

 

If the locking band would be Part below and part above the roof it doesnt sound like the layout was very well designed...was it a signed off install?

If you look at the video I posted in a recent thread, thats a Convesa h cowl with a standard locking band. were above 700ft in the teeth of the prevailing wind and it hasnt blown off in 5 years

 

Nothings  blown off mine and was absolutely fine until I raised it. I raised it as it was slightly lower than the ridge and every now and then when the wind blew a certain way I'd get a bit of a down draft. So I extended it 500mm using a structural band. The cowl is clipped on using the standard clip band it comes with. 

I thought I was just being 'belt and braces' using the structural band as it's last support brace is the upstairs ceiling joist which is 1300mm from the top  of the flue pipe, then the cowl on  that.

The structural band is possibly not needed as they can be 2meters unsupported it says online. But we seem to get very strong winds these days. 

[slim reaper]

You should have a roof support in the rafters and no joint within a certain distance of any floor ,ceiling or roof rafter spaces so the joints can be inpected. But in any case the joint should not leak ,have you raised the question with the supplier

https://www.stovecentre.ie/product.php?id_product=522

Do you have a picture of flue and roof

 

Edited January 23, 2021 by slim reaper

[JT19]

All joints can be inspected and non in the joist or rafter space. It comes out right by the eaves so the rafters it goes through is about 200mm  from the joist it just went through where it has a support. 

There isn't anything wrong with it. Its just the convesa structural band not sealing! 

[slim reaper]

All I can think of is that the band is forming a reservoir that holds  the water higher than the inner skin spiggot and the wind blows it though the vertical gap in the band?

300 degree silicone is more than adequate, I bet you dont feel any heat there at all

[PhillH]

Hi.@JT19 did you find anything?

[JT19]

1 hour ago, PhillH said:

Hi.@JT19 did you find anything?

Hi Phill. What's  happened is convesa have changed the way thier flues lock together. So even  though it's  all the same make the last 500mm on my flue is actually different to the rest. I have had to modify the structural band that clamps the last  500mm pipe to the rest of my flue.

I've had a fire going since  Saturday and all seems well. 

 

[PhillH]

Hi Phill. What's  happened is convesa have changed the way thier flues lock together. So even  though it's  all the same make the last 500mm on my flue is actually different to the rest. I have had to modify the structural band that clamps the last  500mm pipe to the rest of my flue.
I've had a fire going since  Saturday and all seems well. 
 

Hi @JT19 glad you have solved the problem, hope it’s stays that way. Thank you for your feedback.