I am after some advice. I have recently bought a new house with an old back boiler. My initial plans were to change the boiler for a new traditional gravity fed system or a combi. When my plumber came to have a look he said it was the old single pipe system (this has been confirmed by another) and if i was going to expense of changing boiler may as well change pipework as well and i thought of doing that may as well have new rads as well. Is this worth it or just change boiler?