My Suprima 50 is around 8 1/2 years old but has now developed kettling or banging through the pipes just as it reaches its peak heat before shutting off. I have run a descaler through it and bled everything, I also changed both the thermister and overheat stat but the problem is still there. I have tried different pump speeds and have had to turn the boiler temp right down to make the problem more bearable. I now leave the hot water/heating on constant to keep it warm, as the evening goes on the boiler cuts in and out with no drama as the temperature is constant and doesn`t need much heat top up, however have a shower and the boiler cuts in to warm the cylinder the banging is back. I`m no engineer but have done all the plumbing on this system and its been fine for around 8 years, I`m thinking maybe the heat exchanger is restricting the flow and causing the problem.
Sorry to go on, just wanted to state all the facts.
Sorry to go on, just wanted to state all the facts.