"Christian McArdle" wrote in message
. net...
Can anyone explain the relative merits of heating the heatbank directly
or
indirectly?

Direct enables the full boiler output to be used. Also, you can have as
many
direct heat sources and sinks (i.e. radiators) running off the heat bank,
like a huge Dunsley Neutraliser.

Indirect has the advantage that the controls are exactly the same as a
conventional system. It also allows sealed pressurised primary circuits.
This is good as it allows you a full choice of modern condensing boilers
(some of which can't run vented) and has all the benefits that go with
sealed operation (see the FAQ).

All the top condensing boilers have vented versions: Worcester-Bosch,
Keston, Glow Worm, Ideal, etc. Combi boilers by nature are all pressurised,
but you would not use one of these with heat bank anyway.