The Efficient Home Forum

Thanks for taking the time to respond back to me.

I've got a WB 42CDi so it's not the smallest of boilers. The radiator that the chap suggested I leave is pretty much the smallest radiator in the house and it's on 10mm piping whereas the majority of the system the radiators are over twice the size ...

Thanks, this is a really informative answer which I think I'll talk to my CH chap about.

I've just bought a 16 radiator setup from you with valves and am having the same symptoms as OP with radiators knocking when TRV is barely open.

He just replaced the valves location for location on radiators ...