We've been struggling on with the old Baxi gas back-boiler for far too
long, largely because of the lack of convenient siting for a modern
wall-hung boiler, along with need to completely re-arrangeme the pipe
work that it would entail. But - now there is a Baxi BBU, a condensing
direct replacement (allegedly) to fit in the fireplace where the old one
lives.

It looks promising, well except for the fact it IS made by Baxi!! but
there is no other choice as far as I can tell.

Advantages seem to be, apart from the obvious of not having to relocate
all the pipe-work, 1) it is room-sealed - the old one isn't, 2) it is
claimed 90% efficient, and even if that's an exaggeration, it's surely
an improvement over our cast-iron jobby which is no doubt well less than
65%, 3) The bulky gas-fire front which we don't use can go, and be
replaced by a flat fire-front or nothing, freeing up some space in the
room.

Disadvantages: 1) Needs a condensate drain. Not a problem here as we
have an under-floor space and its not a major job to route it to an
outside drain. 2) Only one size is available (15kW). I would go for a
bigger output if changing to a wall-hung but this should give at least
as much as we get from the old Baxi which just about keeps us warm
enough, and is probably producing well less than 15kW output anyway.

I would dearly love to rip out all the existing system and replace it
with a super-duper sealed system, but for various reasons that's not
practical at present, so unless there are any nasty gotchas that I've
missed I'm inclined to bite the bullet and give this Baxi spit a go.

What do the team think?

Phil

On Sat, 22 Sep 2012 20:55:30 +0100, Phil Addison wrote:

1) it is room-sealed - the old one isn't,

So will need an air supply from outside. How does this fit with a
conventionally flued boiler?

2) it is claimed 90% efficient, and even if that's an exaggeration,
it's surely an improvement over our cast-iron jobby which is no doubt
well less than 65%,

Wander over to http://www.boilers.org.uk and look your current one up.


--
Cheers
Dave.

On Sat, 22 Sep 2012 21:14:58 +0100 (BST), "Dave Liquorice"
wrote:

On Sat, 22 Sep 2012 20:55:30 +0100, Phil Addison wrote:

1) it is room-sealed - the old one isn't,

So will need an air supply from outside. How does this fit with a
conventionally flued boiler?

It has a concentric flue liner that goes up the chimney to replace the
existing flue liner (or maybe it goes inside it?*) available in 10m or
12.5m length. I have to find out how tall my chimney is, its quite tall
being a victorian property so hope these are long enough. I'll be
measuring shaddows next time the sun comes out

2) it is claimed 90% efficient, and even if that's an exaggeration,
it's surely an improvement over our cast-iron jobby which is no doubt
well less than 65%,

Wander over to http://www.boilers.org.uk and look your current one up.

Thanks Dave, I had forgotten about sedbuk, turns out they reckon its 65%
heh-heh, and that presumably was when it was new, its now 24 years old
so I'll have a nice fuel bill reduction to look forward to, and I've
just done a supplier switch which will save me £400/year too (but less
for the new boiler), I oviously stayed with Atlantic too long!

*No, the installation manual says the old liner must be removed.

Phil

On Sat, 22 Sep 2012 16:13:19 -0700 (PDT), Owain
wrote:

On Sep 22, 9:28*pm, "Dave Liquorice" wrote:
1) it is room-sealed - the old one isn't,
So will need an air supply from outside. How does this fit with a
conventionally flued boiler?

Fan-flued with a concentric flue up the chimney.

The real problem in many locations will be the condensate drain.

Owain

Don't most offer a pump as an option now? My MILs pumps up into the
attic and vents into the gutter. I thought it was weird but it seems
to work, having performed through last winter.

On Sun, 23 Sep 2012 00:25:30 +0100, Ericp
wrote:

On Sat, 22 Sep 2012 16:13:19 -0700 (PDT), Owain
wrote:

On Sep 22, 9:28*pm, "Dave Liquorice" wrote:
1) it is room-sealed - the old one isn't,
So will need an air supply from outside. How does this fit with a
conventionally flued boiler?

Fan-flued with a concentric flue up the chimney.

The real problem in many locations will be the condensate drain.

Owain

Don't most

Most?? Do you know of another make besides this Baxi? They claim to be
the only one.

offer a pump as an option now? My MILs pumps up into the
attic and vents into the gutter.

Yes, this Baxi one has a pump. There is a sump at the bottom and the
pump pumps it up to an outlet at the top of the boiler. In my
installation it can go from there through the side of the chimney brest
to join with the existing boxed in pipework. From there it can dive
under the floor boards and cross under the joists and through an outside
wall where it will emerge a couple of inches above the patio level, and
from there a short run to a rainwater drainage grill.

Phil