In article ,
Set Square wrote:
You may have difficulty getting the header tank high enough to prevent
the system from pumping over - unless you've got lots of headroom above
the new living accommodation.

Unless you've got a flat roof, I'd say there'd be plenty room for a CH
header tank. The domestic water tank is usually the problem.

The head on my system is probably less than 6 feet from top of rad to
water level in tank, but works fine on over three stories.

--
*Great groups from little icons grow *

Dave Plowman London SW 12
RIP Acorn