"Andy Hall" wrote in message
...
On Wed, 1 Sep 2004 13:54:06 +0100, "IMM" wrote:


"Dave" wrote in message
...

I think a couple of people installed Heat Banks last year - what are
your
views having run them for a while?

Can anyone explain the relative merits
of heating the heatbank directly or
indirectly?

When direct "all" the boilers heat goes into the store. When indirect
you
are relying on the efficiency of the coil.

Why would I choose to make the primary
circuit pressurised or vented?

In theory pressurised has little advantages over vented when using a heat
bank, as long as the system is fitted correctly and inhibitor is used and
replaced every 3-4 years. Pressurised does away with the F&E tank, in a
heat
bank this can be integrated with the store.


Also making the primary pressurised with a direct heatbank (i.e. the
bulk contents of the cylinder are pressurised) means that for Building
Regulations section G purposes it counts as a sealed storage system
and must therefore be installed by a certified installer.

Not according to RCM:
"Thermaflow is a primary water thermal storage unit that supplies mains
pressure domestic hot water at good flow rates in accordance with the
requirements of BS 6700.
NHBC and the Water Heater Manufacturers Association Specification.
The thermaflow system facilities easy installation without the requirements
for building control or BBA approval and is readily incorporated into
traditional or modern central heating systems. NO MORE NEED FOR COLD WATER
STORAGE TANK IN YOUR ATTIC."
http://www.rcmgroup.co.uk/files/ThermaflowINST.pdf

This is a "pressurised" thermal store to assist combi's and give higher
flowrates.