Hi all Got a gas BAXI boiler, which was driving me and my wife crazy lately with loud (only describe as ghostly) noises, not all the time, more for half an hour on first start up and every now and again while it was on. Everything -heating and hot water working fine. Got my usual plumber up, who first along with me bled the system and radiators umpteen times looking for air and eventually diagnosed the pump. A new pump was installed today, and after about 30 mins- the noise is back. Putting a screwdriver and poking it around to listen, the new pump is quiet but it seems like the noises are coming from the heat exchangers in the boiler. (only started about 2 weeks ago was fine until then and system has had nothing done to it for over a year). Now even my plumber is stuck- is as frustrated as me- and doesn't know what to do next, any ideas? Much appreciated!!!