When the heating system is on there is an almost continuous flow of hot water from the overflow pipe into the expansion tank. It only seems to do it when the heating is on, not when the hot water is being heated up. Should it run all the time? Its very noisy and sounds like a mini waterfall in the loft!
The other problem is that when the water starts to heat up the radiators go cold - don't know if that's related problem or something else?
I know it sounds stupid, but from what you say it sounds like the pipework is plumbed up incorrectly, especially if as you say it's like a waterfall when you turn on the heating. Trace the pipework from the boiler, sounds like your flow/return pipe has been mixed up with your overflow or vent pipe.
DIY how to tutorial projects and guides - Did you know we have a DIY Projects section? Well, if no, then we certainly do! Within this area of our site have literally hundreds of how-to guides and tutorials that cover a huge range of home improvement tasks. Each page also comes with pictures and a video to make completing those jobs even easier!
by 