Dan S. MacAbre wrote:

Chris J Dixon wrote:
My Bulldog TRVs are about 15 years old. One of them has been
fitted with an electronic control, but has stopped turning off.

Having put back the original thermostatic head, it still seems to
be stuck open, though the spindle appears to move freely.

Before the TRVs were replaced, I had regular issues with them
sticking closed, but this is a new one on me.

I wondered if a some contamination was blocking the valve
movement, and left it fully open for a while in the hope that it
might flush through, but no luck so far.

Any thoughts? I know that in a pressurised system I ought to be
able to quickly dive in and have a look once I have let the
pressure out, but I really don't want a sudden gush of black
liquid in my lounge.

Here's a wild guess from someone with only a little experience of
fitting them :-) Does it have a 'pin', like all mine have? Can you
push it in if you press hard enough?

As I said above "the spindle appears to move freely"

Chris
--
Chris J Dixon Nottingham UK
@ChrisJDixon1

Plant amazing Acers.