"Andy Hall" wrote in message
news
On Wed, 1 Sep 2004 14:40:49 +0100, "IMM" wrote:


"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.

These are available, but rare and termed directly pressurised.

I wanted to make the point because there are direct heatbanks on the
market and it is not always immediately obvious that they are not
suitable for pressurised primary operation.

They are suitable.

Having the primary vented, whether with an integral F&E tank or not
means that this can be a DIY job, although is still subject to a
Building Notice because of part L1.

However, some boilers will not accept
having an open vented primary,

Few and far between.

I've got one.

You have not got a heat bank.

There are plenty of state-of-the-art condensing boilers
that are vented.

Of course, and there are quite a few around that won't accept open
venting. I simply raised the point so that it is not overlooked.

so the choice then becomes making
the heatbank a pressurised one
(professional installation) or having one
with a coil on the input
side from the boiler (primary is pressurised)
and the bulk water in
the heatbank being tertiary and open vented
and separate from the primary. This can be
a DIY installation with Building Notice for
part L1.

Another point here is that if a heatbank is direct and is using an
internal tank for the F&E, it muct be installed so that the tank is
above the highest radiator.

About the only constraint.