Radiator valve hiss

[sausagehead]

Wondered if anyone has a simple fix ? , i have two thermostatic radiator valves that have decided to make a high pitch whine , the noise stops if you adjust them slightly.
Any good news to how i can easily fix this greatly appreciated.

 

[ChrisR]

Turn down the lockshield valve at the other end. Try with it only one turn open.

 

[JohnD]

I wonder if they're at the wrong end (inlet or outlet)? Mine claim to be bi-directional and have arrows on them, but there used to be a "recommended" end that I can't remember now. Are they different to other quiet valves in your home?

 

[sausagehead]

many thanks ChrisR - i will try this
- JohnD - this is a new problem and the valves used to be quiet, as i understand it they are supposed to be able to go on each end?, have the same valves elsewhere with no problems.