"Christian McArdle" wrote in message
. net...
From the DPS site:

"GX units are only suitable for a vented boiler / heating systems with
a Feed & Expansion Tank."

I've never seen a presurised heat
bank advertised.

They are available.

You lose many of their
advantages by doing so.

Not so. It depends on the application, such as having the boiler on the
ground floor and the boiler dumping "all" its heat.