Boiler flue issues - basement and flue termination

[ShaunCorbs]

Do you have an example of the kit I should change it with? I'm still not sure I understand what my current setup is doing wrong

your air intake is below the ground so could get blocked / submerged

and best ask a gas safe engy to sort it out

 

[Last Plumber]

Hi Shaun

Thanks for helping. Not sure I fully understand your suggestion, what's the difference to a flue and plume kit? (Apologies for my ignorance!)

Hello.
The flue on your boiler has two pipes. One external (large 4" white metal) which draws air into the Boiler combustion chamber to mix with the fuel to create the right mixture and an internal (2" plastic) exhaust pipe which takes away the products of combustion.
In your case the flu pipe exits the building into the dug out and the air intake terminates there. The exhaust is then extended away from the ground, window and dug out to a satisfactory position. However, it is possible for your air intake could become blocked with snow/leaves etc or if the dug out fills with water, that could enter the air intake and ultimately the boiler. Even if you covered it with a mesh guard to stop things falling in, it could still become blocked by things lying over it like the board you have there now.

If the air intake becomes blocked or partially blocked, then the Boiler will not be supplied with enough oxygen to burn safely/correctly. This is why it falls foul of the rules and regulations. It should never have been installed like that really, so it was never fine.

You need to get a gas safe registered person to make the necessary alterations and make it safe.

 

[gmartine]

So can you understand why two gas Safe engineers have failed the setup I have given the outlet for the flue on top of flue extension is 2.5m above ground level. They seem to be solely judging it on height pipework exits the property which is not 300mm above ground but surely the regulations deal with the termination of the flue ie where the gases are escaping and don't care about covered pipework itself?

Yes, I can now...

A "plume kit" or as Vaillant describe a "vertical termination kit" has been used to raise the flue intake from it's termination point to 2.5m (it is not a flue extension) however the flue exhaust still terminates below ground level which is why it has been pulled up. As described above a balanced flue attached to your boiler contains both the intake and exhaust ports, the plume kit will need to be replaced with an actual flue that can terminate at 300+mm above ground level as long as it is caged or above 2m where it does not.

You can see from the diagram that the vertical termination kit is a lesser diameter from the actual flue exiting the boiler, that's because it is only extending the exhaust port meaning in your case the intake (at termination point) will still be below ground level with the potential to get blocked.

Your confusion (and mine a bit) lies in the belief the plume kit is the same as an actual flue and therefore terminates at a legal height, it does not it only partially does via a plume (exhaust) extension kit. Hope that clarifies things.
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Yes, I can now...

A "plume kit" or as Vaillant describe a "vertical termination kit" has been used to raise the flue exhaust from it's termination point to 2.5m (it is not a flue extension) however the flue intake still terminates below ground level which is why it has been pulled up. As described above a balanced flue attached to your boiler contains both the intake and exhaust ports, the plume kit will need to be replaced with an actual flue that can terminate at 300+mm above ground level as long as it is caged or above 2m where it does not.

Corrected, sorry way around.
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Yes, I can now...

A "plume kit" or as Vaillant describe a "vertical termination kit" has been used to raise the flue intake from it's termination point to 2.5m (it is not a flue extension) however the flue exhaust still terminates below ground level which is why it has been pulled up. As described above a balanced flue attached to your boiler contains both the intake and exhaust ports, the plume kit will need to be replaced with an actual flue that can terminate at 300+mm above ground level as long as it is caged or above 2m where it does not.

You can see from the diagram that the vertical termination kit is a lesser diameter from the actual flue exiting the boiler, that's because it is only extending the exhaust port meaning in your case the intake (at termination point) will still be below ground level with the potential to get blocked.

Your confusion (and mine a bit) lies in the belief the plume kit is the same as an actual flue and therefore terminates at a legal height, it does not it only partially does via a plume (exhaust) extension kit. Hope that clarifies things.
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Corrected, sorry wrong way around.

 

[Mjward]

Fantastic. Thank you...I've gone from completely baffled to 100pct understanding the situation now.

I think cheapest solution is to take the flue vertically up into the room above and then horizontally out which would be greater than 300mm.

Much appreciated

 

[gmartine]

I don't think they're will be a great deal in it tbh as the new termination point will need to be core drilled again. Get a couple or three quotes and see what the engineers recommend as it looks like you have a couple of windows in close vicinity.

 

[Mjward]

I don't think they're will be a great deal in it tbh as the new termination point will need to be core drilled again. Get a couple or three quotes and see what the engineers recommend.

I've got a plumber I've had good success with recently who estimated it as £250-350 which seems reasonable

 

[AlsPlumbing]

Well, I've just come across this thread for the same reason. I too need to fit a new boiler in the basement and find a means of a good termination of the flue.
My plan was to do exactly as Mjward suggested in his original drawing. Which only shows a Flue and doesn't go into detail of the air intake. - which is fine. ( no talk of plume kits)
If it is terminated above ground ( at the correct height) then the only draw back I can see is Ingress of rain, snow or leaves which would gather in the ' cut out' opening or pit which allows the flue to exit the basement in the first place.
So, my plan would be was to build a small structure around this with pitched roof. build a couple of doors on the front and then this would give access to inspect any joints on the outside of the property and of course would keep it weather tight.

please let me know your thoughts.

 

[king of pipes]

No no no ! You can't do that must be open all sides it can have a wire mesh guard fitted around the air intake . Kop

 

[gmartine]

Any chance of running the flue internally, check your boilers MI's as you should be able to run the flue quite a distance horizontally before turning upwards.

 

[AlsPlumbing]

Any chance of running the flue internally, check your boilers MI's as you should be able to run the flue quite a distance horizontally before turning upwards.

Unfortunately not. My customer said his kitchen cupboards will sit over this spot.
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No no no ! You can't do that must be open all sides it can have a wire mesh guard fitted around the air intake . Kop

Cheers for reply.
Yes, I know this, but the terminal will be outside. It would be off a vertical flue with pitched flashing coming out from the 'cupboard pitched roof' only problem i think would have is the external wall distance, which i'm going to look up now. Anything more than 300mm, I'm probably stuffed!