"Christian McArdle" wrote in message
.. .
A *properly* designed one won't pump over.

I rest my case.

Why? It's not difficult.

Clearly you have greater faith in the majority of people installing these
systems. It is a lot harder to muck up a pressurised system. You are also
much less likely to end up with a dangerous result, although obviously any
system can be dangerous if done too incompetently.

There are bound to be problems with poorly installed pressurized
systems too come to that - leaks for one.

Well leaks are common to all plumbing.

Inhibitor is essential to open vented system in many area. Most people do
not re-dose after 4 years.

A sealed system does not necessarily require the stuff, with the vast
majority of systems getting away with it if none is installed. In fact too
much of it, like in one bedroom flats having a full bottle which is good
enough for a 5 bed house, and the expansion vessel diaphragm can perish -
which often does. The inhibitor acts against rubber - an the O rings in the
rad valves..