i have an ideal icos he24 boiler.over the last 6 months the system has slowly developed a very very loud banging noise.this noise only happens when the domestic hot water comes on (central heating off).the boiler comes on with a small bang then the pipes from the boiler to the immersion heater make 3 or 4 loud bangs.the boiler then stops then starts (not on the timer)again banging.heating engineer came out, said the water is too hot ,turned it down ,no differance. any help appreciated.
I had this with an Icos combi and it was dirt in the system, causing the boiler to overheat enough to bang but not to go off, honest opinion, get shot of it ! terrible boilers loved by builders hated by engineers.
