I have 2 of my radiators changed for more powerful ones as the old ones were far to small- very pleased and happy and warm now- thanks for advice on previous thread . At the same time we had TRVs put on all the radiators except for ones that didn't need them. My bedroom radiator has always been noisy but now is very noisy and so is spare room's (two highest rads) have bled them. Still noisy, saw another thread about turning lockshields off and balancing them. So dived right in and turned off lockshields and began turning both on a quarter. No noise, but they were both fully open before so how open do they need to be- keep going til they get noisy again?