by plumbbob »
Fri Oct 03, 2008 10:03 am
You don't need to worry about any contamination of water as all the central heating and hot water heating circuits share the same water anyway. Inside the hot water cylinder, behind the two side connections, is a large heat exchanger coil round which the heating water circulates so the two waters are always kept entirely separate.
Your suggestion that the radiator being plumbed to the gravity feed side would make it work as a summer radiator does hold water (sorry).
My only concern would be is because the heating return is utilised, this crossover could, depending on exactly how the system is plumbed, cause a reduced or unexpected flow in the heating circuit thereby reducing its efficiency. You could also find that radiator doesn't heat up as much as the others.
If your system works all right, no harm is going to be caused by leaving the plumbing as is.