Baxi Bahama 100

Horrendous noise and vibration causing cracking in walls. Boiler 4.5 years old, regularly serviced and looks after just five radiators. Has always got progressively noisy within 2 or 3 months of each service but now intolerable. Fernox Silencer put in 5 weeks ago. No joy! Baxi enginner out this week - replaced pump, 2 flow valves and water to water exchanger. Said system had not been chemically cleaned when installed and problem was magnetite and limescale. Suggested treating with two tubes of Fernox restorer (injected yesterday). When he left, system was a little quieter - not silent - but not now. We are back to the Red Arrows in display mode.

Help and advice appreciated.

I had the same problem after about 2yrs since fitting .Found that the fitter had not cleaned the system out after installing and the filter on the return was badly blocked,replaced same ok now.