I have a coal back boiler that heats the hot water (there's also an immersion) and 6 radiators using 8mm pipes. Ideally I'd like to replace this with gas central heating, but the costs of removing the back boiler and getting connected up to the gas mains, I'd like to try to save a bit of money where I can. Is it possible to use the existing 8mm pipes on a new gas central heating install?