New house now 2yrs old tapping noise has always been there, plumber tried to convince me it was expansion noise, I understand expansion/creaking/tapping etc.this noise gets louder the longer the heating is on. Same senario for two years.the tapping gets louder and quicker then slows down till it stops. Waits e few seconds(maybe 30 or so) then starts up again, gettind stronger and louder then followed by a loud bang,like someone hitting an empty tank.It appears to be the first radiator in my ensuite which heats up first,noise starts there, and goes across under the floor to the main double rad in my bedroom.I would love someone to solve this problem for me,so I can go back to peacefull sleeping and waken up to my alarm clock 1st thing in the morning. Thank you micky.

Has anyone ever double checked to see if there is any air remaining in the system?

It sounds to me like you have expansion noise. I guess the installer did not take that into consideration. Naturally check for air as the first reply suggested also.

The problems with noise is it can have many possibilitys. Your best bet is to get someone local who can actually hear it and start checking for possibilitys. Not the same person you had before but a trained boiler mechanic with lots of experience.