On Mon, 15 May 2006 17:05:23 +0100, TheScullster wrote
(in article ):


"Andy Hall" wrote


Is your boiler suitable for sealed operation?

The boiler is Glow Worm Space Saver 50.
How would I find if it is suitable for mains water pressure?

Ask the manufacturer. I used to have one of those and it's a pretty old
design, so I somehow doubt it it's suitable.


I hope to draw up a schematic of the current system and will post a link.
This shows that, with hot water solenoid valve closed, there is a
significant distance between the make up water connection and the vent - a
point that you have made in previous posts concerning pump over.
My belief is that, as part of an "upgrade" to the system 10 years ago,
thermostatic valves were fitted to many rads by previous owners (or people
appointed).
Due to the poor plumbing layout, this would (from my experiences of the
system) lead to regular pump over. In other words, when all the radiators
ran "cracked", it would possibly have worked OK. But as more rads shut
down, water just pumps over, even on pump speed 2.

With correct pipe layout, pump over can be prevented regardless of the number
of TRVs. It just means that there is too great a pressure differential
between vent and FE pipe. This can easily be fixed by bringing them closer
together on the circuit - no more than 150mm - or put in an air separator.

Did I remember you saying that you were planning to replace the boiler?
When I did my system refurbishment, I removed the boiler and installed
isolating valves. I then converted the syste,m to sealed operation,
flushed at the radiators and fitted the new boiler with a strainer on the
return.





Will make this the subject of further thread

Thanks Andy

Phil