Weird "stuff" around TRV pin.....

Hi,

I've just been checking my (Honeywell vt200) TRVs, making sure the pins all move freely.....and noticed that the ones downstairs have a weird red'ish residue around the pins, and the pins were noticeably harder to move than the ones upstairs (they seem fine now, but initially they were very stiff). I almost wanna call it rust, but it wasn't.....quite. I've got a sealed system, GlowWorm condensing boiler.....erm.....recently had a boiler service and inhibitor added.....(whole new system fitted 3 years ago, including boiler, rads, TRVs).....

So, can anyone suggest what this "stuff" could be? And, is it safe to just free-up the TRV pins yearly, say, or is this fighting a losing battle.....?

Thanks in advance for any info,

Matt

most likely be the silicon grease used to keep em moving has a bit of general dust around nothing to worry about

a wee skoosh of wd40 and work pin up n down a couple of times will help

Thanks glasgowgas, your reply is much appreciated. That's one less thing to worry about now then

Cheers,

Matt