SMPW wrote:

My existing floor standing boiler has now died on me and I have now the
opportunity to buy and install a more efficient boiler. The problem is
that the house (1901 circa) has the original single pipe system (mild
steel pipe work) that is gravity fed and runs throughout the whole
house servicing 20 rads.This in itself seems to be a problem if, as per
building regs I go down the line of purchasing a condensing boiler, as
I believe there are a number of issues.

I can't think of any additional problems that a boiler being a condensor
will add over and above those you will find with any modern boiler
trying to drive a single pipe system. With a large system you will
probably need to run a high flow and return temperature to get enough
heat out of the last few rads in the system, and this will in turn
reduce the efficency gains you get from a condensing boiler - but it in
itself won't be a show stopper. You would need to choose the boiler with
care if you want to keep it as a vented system since not all modern ones
can drive an open vented system.

British Gas have a policy where buy they won't touch the system as far
as the installation of a condensing boiler is concerned and GASFORCE
quoted £10k to install a 65 kw commercial boiler (the new boiler would
be sited about 6ft from the old boiler) which to me seems a rip off.

'kin ell as they say! Did that include an upgrade to the gas meter etc
to supply that amountof gas? (i.e. just over the official limit for most
domestic meters).

How muc heating capacity do you actually require? Have you done heat
loss calcs for the whole house? (if not, now is the time!)

How difficult would it be to upgrade to a two pipe system? If that
sounds idfficult, what about with microbore?

My preference would be to for a condensing boiler if it can be
installed and provide the efficiency over a non - condensing boiler,
although I have yet to speak to a plumber who
can give consistent advice. Would it be better to go for a high
efficient gas boiler assuming I get an exception cert.

The only difference between a modern condensing boiler and a
conventional one is the use of a larger heat exchanger (or secondary one
if you buy a scabby boiler), and a condensate trap and drain. Both will
otherwise be stuffed full with electonics, fanned flues, and other
stuff. So it is not the same argument as say sticking with an old cast
iron lump because "it is simple, and there is not much to go wrong".

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/