Hello, I've recently experienced a problem with the above boiler. Boiler is 10 years old and has become noisy. Gas engineer put Fernox F2 boiler silencer into system. This exposed a noise which sounds like drums being played inside the boiler! This only occurs when the boiler is fully surging in power, usually around 70 degrees. The HEX has been cleaned, fan replaced and now system is being cleaned with Fernox F3. The diverter valve is sticking slightly and is being replaced next week. I took a video illustrating the noise this pm after the cleaner had been applied. Here the boiler is surging before it cuts out. Can anyone identify the noise?
https://1drv.ms/v/s!Aq7r42kkeO1ngs4GzkON-AfGf-qs_A
Thanks for any advice
Tony
https://1drv.ms/v/s!Aq7r42kkeO1ngs4GzkON-AfGf-qs_A
Thanks for any advice
Tony