When I turned the heating on, I noticed that I had one radiator that wasn’t warming up and a quick examination showed that it was due to a stuck TRV pin. During the warmer weather over the last couple of days, I sprayed WD 40 on the pin and left it. Then this morning due to it being a cold misty morning here, the heating came on and the TRV worked again.
Of course, I had to get some more because I couldn’t find my can of it. Which will no doubt turn up when I am looking for something else.
For those interested, a link to the history of WD-40
Be careful with WD40, it can damage some plastics and it might be the TVR pin seal has a plastic content.
I too have experienced sticking TVR’s, for the last 5 yesrs or so I’ve put a few drops of 3-in-1 light oil on the pin about once a year. This year I didn’t do that but all TVR’s worked OK on their 1st season heat up.