Recently two of my Rads TRVs have started to make a high pitch whistling noise, it get's to a point that it gets so annoying I have to turn the TRVs down on the effected RADS, which obviously cools the Rads down. What's causing this issue? could it be the TRV's that are faulty or is it something else.
my plumber installed these cheap TRVs when I had my RAD's upgraded.
White & Chrome Angled TRV with Lockshield 15mm | Thermostatic Radiator Valves | Screwfix.com