I've read that the primary circuit to the cylinder must be a continuous rise from the boiler, but haven't been certain as to why. Is this to prevent air locks?
The way I'd like to route the pipes will have a continuous rise to the cylinder, with the exception of a t-junction heading downwards before rising again to the gravity fed radiators. Any air in the system will end up at the top of the radiators this way.
Anyone shed light on this? Is what I propose a nightmare for some other reason?
cheers Danny