On Mar 8, 6:57*pm, M.Joshi wrote:
We have a loud banging coming from a small Worcester Bosch boiler which
goes away when a radiator valve or TRV is adjusted.

Is this indicative of a faulty valve or TRV?

Thanks.

--
M.Joshi

Probably cavitiation. Reduced pressure due to the circulation pump
causes steam bubbles to form and collapse.
This can be confirmed by seeing if it goes away when the BOILER stat
is turned down.
Could be a blockage somewhere. Or a wrongly sized/set pump.
It wants looking as it could be very damaging.