Just had the small radiator in my office replaced with a larger vertical column radiator. The old one has an old valve with HR92 and an adapter - the new one has a brand new valve and the same HR92.

It is making a loud rushing sound when on, reminiscent of a washing machine or dishwasher filling up - no gurgles and the radiator is bled. Same as discussed here: https://www.diynot.com/diy/threads/r...-valve.342716/

It's coming on/off for a few minutes at a time and quite distracting, really rather loud. I notice that while the in-pipe (the one with the TRV) gets nice and hot, the radiator itself never gets particularly warm. I had put that down to the fact it's a 10,000 BTU 4-column monster but now I wonder if something else could be causing both things?

Can anyone help me diagnose what might be causing this - is the noise source likely the radiator or the valve, and what if anything can I do about it?