On 07/01/2025 20:58, Chris Holmes wrote:

Also, the head is barely hand tight

That's normal the head doesn't need to be more than hand tight.

You can remove the head. The head doesn't form any part of the seal

I suggest that you establish where the valve (TRV) is leaking.

Remove the head as shown in this video https://www.youtube.com/watch?v=dwh3-JSQxWw

Dry the valve with some kitchen roll

Is the valve leaking from the central pin or is it leaking from one of
the nuts to the pipes? Dap dry kitchen roll to the individual parts to
see which part is dripping water.

The central pin can be pushed in and it should spring back.

See also someone checking the pin is moving https://www.youtube.com/shorts/CWYKUAb-Acg

and doesn’t have any PTFE tape or
anything else to seal the threads

The threads on a compression fitting don't need PTFE tape - that's not
what seals the valve. There will be an olive on the pipe and radiator
tail - it's the olive that seals the valve.
https://youtu.be/zcZ-fMLTun0?t=13




should it have something / be tighter?

Any other thoughts / suggestions as to what is going on?

It is a pressurised sealed system, so perhaps that is why the liquid is
clear rather than the black we previously hot when the system was drained (when it wasn’t a sealed system).

--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

alan_m <[email protected]> wrote:

On 07/01/2025 20:58, Chris Holmes wrote:

Also, the head is barely hand tight

That's normal the head doesn't need to be more than hand tight.

You can remove the head. The head doesn't form any part of the seal

I suggest that you establish where the valve (TRV) is leaking.

Remove the head as shown in this video https://www.youtube.com/watch?v=dwh3-JSQxWw

Dry the valve with some kitchen roll

Is the valve leaking from the central pin or is it leaking from one of
the nuts to the pipes? Dap dry kitchen roll to the individual parts to
see which part is dripping water.

The central pin can be pushed in and it should spring back.

See also someone checking the pin is moving https://www.youtube.com/shorts/CWYKUAb-Acg

and doesn’t have any PTFE tape or
anything else to seal the threads

The threads on a compression fitting don't need PTFE tape - that's not
what seals the valve. There will be an olive on the pipe and radiator
tail - it's the olive that seals the valve.
https://youtu.be/zcZ-fMLTun0?t=13

should it have something / be tighter?

Any other thoughts / suggestions as to what is going on?

It is a pressurised sealed system, so perhaps that is why the liquid is
clear rather than the black we previously hot when the system was drained
(when it wasn’t a sealed system).

Good advice.

I would add.

If it is leaking around the small pin, it is probably done for.

The pin is driven by wax / oil. If the ‘container’ for that is leaking, which I admit I’ve never heard of, the valve won’t work as it should.

Compression joints, if correctly fitted, rarely leak unless the pipes move
due to being unsupported. A couple of pipe clips will usually stop it
happening again. On a central heating system, securing pipes is especially important as the pipes move a bit due to expansion / contraction over time.


Oh, avoid pulling the pin. Tap the valve and turn the pin. It should free
up if it is stuck.

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On 07/01/2025 20:58, Chris Holmes wrote:

I don’t know if the system having been so cold (though not frozen I think) for a number of days has caused the issue.

Are you sure that it not just a bit of condensation forming on the
outside surface of a cold metal valve?



--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)