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.




--

..andy

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