John wrote:
"fred" wrote in message ...
In article ,
Richard J. writes
In our terraced house, we have a Ferroli Modena 102 combi in the
kitchen, with a horizontal 100mm concentric flue of 0.5m length,
ending on the outside wall which at that point is part of a
single-storey extension to our house. Unfortunately, it's rather
close to next door's kitchen door and patio, and the smell of the
initial exhaust when the boiler starts up is quite noticeable.

According to the manufacturer's manual, the maximum flue length
is 4m, but any bend counts as 1m, so a horizontal flue like mine,
attached to the top of the boiler by a 90deg bend, has a maximum
length of 3m, after the bend.

Fine, I thought, I can add a 90deg bend where the flue emerges
from the wall, and then a 1.5m concentric flue going vertically
upwards to end about half a metre above the top of the wall.
That would be an effective length of 0.5 (existing) + 1 (new
bend) + 1.5 (new flue) = 3m. But my local Corgi-registered
plumber says that you can't mix horizontal and vertical flues in
this way, and he says Ferroli confirmed this to him. The only
answer would be a new vertical flue system which would have to
pass through the existing flat roof, which I am reluctant to do.

If the boiler will accept either horizontal or vertical flues,
why can't you mix them?

I don't see anything wrong with what you suggest and it would
appear that ferroli don't either: [...]

[...] as others said talk to Ferroli and maybe fax them a dimensioned
sketch of your proposal

Thanks for all your advice. I e-mailed Ferroli last night with a sketch
of what I wanted to do, and got a reply this morning saying it *was*
acceptable. Must have been a misunderstanding somewhere when my Corgi
spoke to them.
--
Richard J.
(to e-mail me, swap uk and yon in address)