John Stumbles wrote:
On Sat, 20 May 2006 02:44:58 -0700, wrote:

... we are planning on putting the new boiler and DHW tank in
the loft.

Following research on google we have decided that an indirect Pandora
heatbank best fits our DHW needs
...
The Pandora I have initially specified is 180l / 100kw / inlcuding two
2 port valves (S plan) that would serve heating/DHW.

That's going to be fun to get into your loft!
(and to site safely)

Now the main issue - choosing an appropriate boiler to cater for the
heatbank and also serve the heating (radiator) system. Following
various discussions with my plumber we have calculated our heating
requirements at around 26kw and to err on the side of caution we are
looking at boilers between 28-31kw.

That's an awful lot of heat. How many rooms does your mansion have, to the
nearest dozen? :-)

Have you checked with the whole-house calculations on

http://www.est.org.uk/housingbuildin.../boilersizing/

and

http://www.idhe.org.uk/calculator.html

(Note that the latter is wrong for mid-floor flats, at least.)

I'd expect to size a boiler at around 10-15kW for normal sized houses.
OTOH if you can afford a Pandora and a MAN then maybe you also have a
house with that sort of heating requirement :-)

Admittedly I have left most of the calculations to the plumber but the
house is probably slightly larger than average, detached and rather
draughty underfloor (1928 built). As DD has pointed out in choosing a
fully modulating boiler it should adjust where necessary...

I could opt for a more economic solution however having reserached the
market there seems to be much of a muchness amongst the cheaper to mid
range boilers and choosing between them seems to be very difficult
however, the Man and a couple of others come highly recommended and do
seem to stand a little above the rest in terms of functionality and
build quality. Horses for courses I guess as they do cost considerably
more as well.

As stated above I am employing an installer to do the actual fitting
and this in itself has it's own complications especially as he would
rather I go for a cheaper more mainstream boiler but I haven't yet
given up hope of converting him.

SWMBO, of course, doesn't understand why I am going to all the trouble
of speccing such a complex and expensive boiler I am still working
on her although as soon as I mention outside weather compensation she
sends out a huge sigh!