On Wed, 16 Feb 2005 16:15:07 +0000, Andy Hall wrote:

On Mon, 14 Feb 2005 17:54:26 +0000, Doctor Evil
wrote:


Christian McArdle Wrote:


Doctor Evil Wrote:

Take both zones of a heat bank with a pump on each. The heat bank
makers
will install two flow and return tappings on the bottom of the heat
bank
for the two CH zones. The best way.


Although if the zones start to multiply, you can always share a tapping
on a
pumped circuit, if you're careful.

Personally, if I was designing a system from scratch, I'd be tempted to
have
one tapping, one pump, a "manifold" and an S-Plan system, rather than
go
multiple pump, which can have issues with parasitic circulation (or
noisy
valves to cure such) in some cases. Also, zone valves can be cheaper
than
pumps, which may be an issue on multiple zone systems.


A heat bank/thermal store, presents you with a wonderful neutral zone.
Pumps are not expensive and are far more reliable than 2-port zone
valves. You put a check valve on each CH zone to prevent back
circulation. Each pump can have its speed set to the needs of the zone.
There will be no parasitic circulation if each zone has its own flow and
return tapping off the store.


This is only true if a conventional boiler is used or if there is a need
to introduce heat from another source such as solar or possibly some form
of stove.

It is not an appropriate technique to use if a modulating, condensing
boiler is the primary or sole heat source since the boiler will not be
allowed to ever operate in its most efficient temperature range.

I can think of other reasons to operate a heatbank - mains pressure hot
water without using a combi for one.

Perhaps a good reason not to bother with a condensing boiler then (yes, I
know about the supposed law mandating them, more b*ll*cks interference in
my home by the government blah blah...)

Tim