Recently my heating pipes under the floor upstairs in my house have been making very loud noises, rattling around and generally sounding like a train is coming down them! This happens first thing in the morning mainly but occasionally in the evenings. Both times are when the boiler comes on to heat the tank. I havent got the heating on at the moment as it is summer! so I am confused why the heating pipes would be making that noise?
I thought it may be air in the system so I have tried to bleed the radiators but there was no air and all seems fine.