On Sun, 12 Feb 2006 02:45:31 -0800, harry wrote:

Thanks Ed
Is there an easier way round this?
Whats stoppping an upstream flow if the cylinder return is first by the
boiler?

Nothing. Either the cylinder should return after the radiators or the
radiators returns should join together before joining with the cylinder
return.

If the return pipework is not easy to modify then zoning the two sets of
the radiators (if that's a reasonable idea) would also fix the problem.

--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html