On Wed, 08 Sep 2004 01:39:33 -0700, Mark Begbie wrote:
Thanks for the info, I'm getting more mentally clear about this by the
day. So to answer some of your questions.
The current setup is a cold tank in the hall cupboard with hot
cylinders in the lounge cupboard heated by an immersion. There is no
boiler at all in the house with the only heating provided by a gas
fire in the lounge (heading for a skip). Space is very tight (I have
a lot of stuff!) so I am keen to go down the combi route and get rid
of all the tanks. Also I can't remember when I last had a bath (yes,
obvious riposte duly noted ;-) )
The system I am planning to put in is a combi running a feed and
return loop to the radiators, so it sounds like I should really be
using 22mm for the loop. Plan is for barrier Hep2O with copper
through the floor. The boiler I was looking at is a Glow-Worm 24cxi
as a) it's a condenser b) it modulates down to only 4.95kW and c) it's
available from energysmart. Everything except (probably) the lounge
will be on TRVs with a roomstat for the final rad.
I am now leaning toward overrating the rads so that the total is
closer to the boiler output (18kW) than the "required" value of 6kW
that the online radiator calculators come out with. Probably put in
about 12kW worth of radiator area.
My master plan is to do all the installation and then get a CORGI
engineer in to pressure test and hook in to the gas supply.
Since you are a shower man a 24kW unit will be quite adequate.
That is the water heating power. A condensing model will try to
modulate down to the few kW you need, it will likely do a much better job
than a non-condensing unit could do.
Make the radiators up to about double what's needed by the heat loss
program. There is no need to be too strict about this, if say, there
are places where you don't wish to have the extra width or depth or rad.
I'm interested to hear from anyone who has a condensing combi.
I want to know what your experience of it is.
I would be happy to fit Vaillant Ecomax 8xx units but the (trade) price
is really to high ATM.
--
Ed Sirett - Property maintainer and registered gas fitter.
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