On Wed, 6 Oct 2004 00:40:02 +0100, "John Aston"
wrote:

Many thanks to Andy Hall and others for their help earlier this year on the
design of my new plumbing system (http://tinyurl.com/3pwck etc.).
Unfortunately, thanks to a few months illness, I'm still at it - with a few
issues to resolve.

A question regarding an unvented domestic hot water system: Cambridge Water
tested my incoming main supply and informed me that the pressure = 2.8 bar
and the flow rate = 25 litres per minute. Is this sufficiently high for an
unvented supply feeding a family home containing two power showers, a bath,
five sinks, three toilets, a washing machine and a dishwasher?

Hi,

Before going for an expensive solution it may be worth checking that
they don't mean 25lpm _at_ 2.8 bar.

Also a garden tap is quite restrictive, a better measure would be to
open all direct mains taps at a time when the mains water pressure is
likely to be lowest.

[For information, the hot water will be heated indirectly in a 250 litre
tank by a condensing boiler. The mains supply pressure will be reduced (to 2
bar?) by a water softener, although a "high flow" softener, such as the
Kinetico 2020c HF, will be fitted to minimise this problem.]

Presumably the central heating could operate as a sealed system, even if the
hot water tank is vented?

One way round could be to use the hot tank as a heat bank with a
tanked supply for the bath and direct mains for the showers, both
heated via separate plate exchangers.

cheers,
Pete.