Jonathan Curtis wrote:

I'm fitting a flue to a new Baxi Bermuda back boiler and have a few
questions.

1)The "flue outlet socket" at the top of boiler hood measures around
5.5". The instructions say that a 5" flue pipe is required.When I offer
up the flue adaptor to the flue outlet socket there is (obviously) a
0.25" gap all round. Is this standard? I've read that this gap is then
filled with fire cement but this gap just seems too much you would think
that they would manufacture the outlet socket smaller than 5.5"
diameter.

2) The holes on the boiler hood for securing the flue adaptor do not
coincide with the holes on the flue adaptor. Is it Ok to drill small
holes into the adaptor then screw the 3 self tapping screws?

3)When fitting the adaptor to the flue pipe and also the liner terminal
do you use fire cement to 'glue' them together or is it sufficient do
just push them together? If so do you smear the adaptor with fire cement
then push it together or push it together then just smear the edges?

4)The boiler instructions state that I should "wrap the gas and water
pipes through the brickwork and within the fireplace opening itself."
What do I wrap these pipes with?

5) Is it really worth insulating the chimney or is this yet another
gimick? If I don't insulate am I correct in saying that I do not need a
plate at the bottom of the chimney?- all instructions I've seen are with
the insulation.

Thanks in advance for any advice -I've done lots of searching but there
doesn't seem to be any good websites on this subject.


You sound like your are attempting to fit a conventional flued back
boiler.
There is _much_ more to go wrong - perhaps lethally - than with a modern
wall mounted fanned flue unit.
The sort of questions you are asking make me concerned that you might
not be 'competent' (see FAQ).

Regulars readers of my postings will know that I'm not one to slag off
all diy activity. However I seriously suggest some help should be sought
for fitting these type of boilers ( which are to be avoided if possible
on several grounds).

Usually for back boilers the spigot of the flexible liner is located
into the top of the draught diverter ("hood"). If the manufactuers
specifiy a material for jointing than that should be used, otherwise
Flue Jointing Compound is a high temperature mastic which will work well
(the flue is unlikely to exceed 120C and FJC is IIRC good for more than
that). Also fire cement needs serious heat to set.

Copper pipes within builders' openings are wrapped in "Denso" tape.
(Ughh!) (Sort of grease loaded felt).

I may be wrong but I thought the flue securing screws were sort of like
clamps/set screws?

Flue liners are finally sealed and secured in place by compacted
rockwool and chicken wire.


--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html