When the CH system starts and for approx 10mins thereafter, I can hear what sounds like a slow dripping noise underneath the floor approx 3ft from the nearest radiator. The same noise occurs when the system switches off, but for longer. This sound can't be heard once the system has been active for a period of time so I'm uncertain whether this is actually a leak or pipework expanding/contracting, etc. I'm not able to check visually as the pipework is underneath a concrete floor. Has anyone experienced anything similar and can offer advice?

Angela, November 2013

Yes its expansion and contraction,there's not a lot you can do apart from digging up the floor,the pipes should have been put inside another pipe to allow for such an occurance

toptrish, November 2013