Thoughts on boiler flues

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I've been having some interesting conversations with my engineers - in one of our properties the boiler is well overdue for replacement, but hasn't so far due to problems routing a flue to comply with current regs.

The boiler is in a garage underneath the flat. At present, the flue goes through a store that belongs to someone else, has a 90˚ bend, then comes out through the wall into a space that's underneath the flat (the garage door is recessed about 6' from the back wall of the building). Sorry, this is the best picture I have at the moment, the door to the right of the up-n-over garage door is the storage space, and the current flue comes through that wall between the garage and storage space doors - it's higher up and hidden by the beams supporting the back wall.
The wall between garage and store runs roughly in line with the garage door, and the boiler is mounted on that.
flat.jpeg


The engineers reckon the only practical way is to go straight though the store and out the back wall, then use a plume diversion to take it away from the steps. I guess that's not too bad, but it does mean it going through a space that isn't part of my property.
What are people's thoughts on that ?

Now, I did come up with a cunning plan.
There is a concrete lintel over the garage door, so can't come through that. But I could core out a hole at 45˚ that would just miss the end of it, and get me between the space in front of the garage door, and inside the garage. I'd also need to consult a structural engineer about the next bit - but the RSJs are "very oversized" (I think the builders simply found them cheap - they were obviously second hand). Since no-one does an intermediate drain point, I can't drop the flue down to come under the beams, so that means cutting a hole through. My plan was to terminate the twin-flue in the recessed area, and just bring the inner pipe through the beams (thus a smaller hole) using plume diversion/balcony kit parts.
But then the engineer throws in a completely unexpected twist. He was reading from the Baxi book, and said that the twin-flue pipes aren't allowed to go outside other than the short section of terminal. And that it has to be seated "square on" to a wall - so the idea of coming out of the garage at 45˚ is scuppered. He then added that (IIRC) Vaillant do allow their flues to go outside - but don't have balcony kits (presumably because they aren't needed.
Does this sound right ?

Am I right that no-one supports dropping the flue (and hence needing a separate drain point) ?

I'm pretty certain it could be done (possibly without cutting the steel, I reckon I could get a 50mm pipe over the top) with a Keston and 50mm uPVC piping, but their smallest model is "a bit big" and the price tag reassuringly expensive.

I can't believe I am the only one in the world with such routing issues :(
 
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I think you have many problems to overcome here and if the boiler flue is currently up under that recess roof then it probably doesn't comply as it is. I don't believe that any option that has it terminating within that recess will comply

Bringing the flue through someone else's property is not advisable, what do you do if permission isn't agreed or withdrawn?

Balcony kit would seem to be the only possible option that may be workable, there are a number of manufacturers that have these available. I assume the boiler cannot be located within the flat with a standard through the wall flue?
 
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Thanks for the answers
I think you have many problems to overcome here and if the boiler flue is currently up under that recess roof then it probably doesn't comply as it is.
Yeah, it's caused some pondering, but the engineers have determined that for the old non-condensing boiler it's still OK - just. Far from ideal as it creates a lot of damp under there which makes the boarding sag and need replacing periodically.
I don't believe that any option that has it terminating within that recess will comply
That was indeed the consensus
Bringing the flue through someone else's property is not advisable, what do you do if permission isn't agreed or withdrawn?
Ws looking at a written agreement to allow it's installation, and access for maintenance.
Balcony kit would seem to be the only possible option that may be workable, there are a number of manufacturers that have these available.
Any thoughts on the limitations my engineers have given, I did a bit of a sketch which might help :

Boiler flue proposal.jpg

They've told me it can't be done as drawn as the twin-wall is "inside only" apart from the end of the terminal pipe. Can't end the air intake where the second 45˚ bend is as they say the terminal has to come straight through the wall so the seal can sit flat on the wall. And they said a different manufacturer allows the twin-wall to be outside, but doesn't have a balcony kit as presumably for a balcony it wouldn't be needed.
Would be so much easier if we could step the pipe down to go under the beams - but of course no-one has an intermediate drain point option that would be needed.
I assume the boiler cannot be located within the flat with a standard through the wall flue?
One of the features of this flat is having the garage - so not having the boiler take up room in a very small kitchen. putting the boiler in the flat would be the absolute last choice - probably behind going all electric :eek: Would also be "quite a bit" of pipework needed to relocate it.
Have considered the other side of the garage, through the wall, then up - but would need a pit for the flue as it would be coming through below ground level, and there's also a soil pipe in the way.
It is no longer allowed and hasn't been for a long time
Is that a hard rule ? My engineers didn't seem to think it was a problem if I had a formal agreement in place to permit future inspection.
Come to an arrangement to purchase the store from the other land owner?
Well the situation is "interesting".
Technically, that store was supposed to be the bin store for 4 flats (including ours) - but given that in front of the garage door is the parking space for our flat, it means restricted access and definitely not enough room to get bins past a parked car. But early on, a lady upstairs got agreement from the other flat owners that she could use it as her flat has so little storage space in it. So while on paper it's still a shared store, in reality it's been part of one of the other flats since before I bought our flat 20 years ago.
And given the lack of space in the flats, I doubt the "owner" would want to part with it anyway.
 

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