O.B. wrote:
My view too. You don't want the hassle of draining down the system
again because cheapo TRV has failed.

Hi Guys, interesting thread, I didn't know that there was such a
variation in quality on TRVs and have always just used cheap 5 quid
jobs. Just wondering what you all mean when you say they fail - I
understood that they all have a limited lifespan something do to with
the wax capsule or something, and therefore the heads will need to be
replaced after a number of years.
Is this what you're referring to? I don't get it as surely the heads
just unscrew and can be replaced without draining down? Or do the valves
fail too?

Cheers,
Ben.