In an earlier contribution to this discussion,
Al D wrote:

One of my hot water rads has stopped coming on. It's the rad
furthest-away from the main feed on the circuit on the upper floor.

I checked the plunger on its TRV, but it moves freely. I don't have
any reason to suspect the other valve. The system was installed about
10 years ago.

The rad seems to bleed OK from the bleed valve.

I tried shutting of all the other rads in the house leaving the faulty
one on, (thinking it might be a system balancing problem) but it still
doesn't come on.

Any suggestions?

Thank you in advance.

Al D

Could be an air lock or a blockage. First, make sure that there is water in
the F&E tank if it's a vented system - or that there's sufficient pressure
in the system if it unvented. Then re-bleed the offending radiator twice -
first with one valve fully open and the other closed - and then the other
way round. [You may have to clamp the pin of the TRV down to close that
unless you have a manual cap for it - or just refit the thermostatic head
with a spacer above the pin, and turn it to minimum]. Bleed a couple of
pints of water out each way. This will ensure that *both* pipes are clear
and free of air. [If you bleed it with both valves open, one pipe could be
blocked but it will still bleed].
--
Cheers,
Roger
______
Email address maintained for newsgroup use only, and not regularly
monitored.. Messages sent to it may not be read for several weeks.
PLEASE REPLY TO NEWSGROUP!