"Stephen" wrote in message
...
On Sun, 2 Nov 2008 11:29:37 -0000, "Michael Chare"
wrote:


As you suggest, you could just have a separate overflow, but that may need
to be 22mm.

You can have the valves and pump in the return. In that case you could
provide a separate 15mm direct from the header tank to the return on the
boiler (avoiding any valves and pumps).

Thank you, an interesting idea; I had not thought of that. Is their
any performance advantage/disadvantage to having the pump and valves
on the return "pulling" rather than "pushing" the water around?



I've not found any disadvantage! The water is still being pushed, just frim
a different point..


--
Michael Chare