Advice Please -Radiator valve stuck/whole body comes loose when trying to open -10mm??

[bilabonic]

Hi all

Been helping my Aunty who has jus minded into a property and it needs a lot of work.

All rads were isolated except fir living room.
I opened the rest and tapped the TRV to get them to open.

I’m stuck on one lock shield, when I try to open it the whole valve comes out and it’s still weeping when screwed fully back in.

It’s looks like an old type lock shield with a taper fit (not compression on the rad tail side).

Also pipe is 10mm but after just looking at pics I took has it been increased to 15mm (red arrow).

What are my options here with replacing/repair?

I would like just to drain rad and just replace the valve body (leave tail in place) but so they still sell the ‘taper’ fit valves?

Anyone advise please.

Thanks very much.

Pics below.

 

[terryplumb]

Looks like a standard lockshield valve , with 3/4 union fitting at the valve tail ,and the 10mm supply pipe has a fitting reducer taking it to 15mm into the valve.

 

[Madrab]

+1, just a normal lockshield. Available in any of the sheds, the issue you may have though is the union end going into the rad tail may be slightly different. The new one may use a rubber seal where the old one may be a brass interference fit, if so they may not be compatible and the tail may need swapped out. Nut on the pipe may also not be the same and may need swapped too. Depends on hold old the one fitted is.

 

[bilabonic]

So it is a 15mm valve.
I really do not want to remove the ‘tail’ going into rad if possible.
That’s what I meant by ‘interference’ fit’ just did not know the correct terminology just needs to be clean (some use paste).

I have had a few valves from Screwfix recently and they have all had rubber seals I think.

Do they still do interference ones?
I might have an old one hanging about tbh.
This is an interference lock shield i removed a few weeks ago. (Pic below)

I just detest removing tails from rads I never seem to get a decent seal even after 15 turns of PTFE. (I’ve also failed with the Locate 55 string stuff in).

I’m wondering have I got an old shield hanging about to fit.

Pic of interference fit valve type.

 

[bilabonic]

Looks like Toolstation no longer do them?

Are interference fits still available??

Angled Radiator Valve CP

Working pressure up to 150psi. Working temperature up to 110°C. Complies with BS 864/2.

www.toolstation.com

Cheers

 

[Madrab]

never seem to get a decent seal even after 15 turns of PTFE

Buy some gas PTFE tape, 7 turns with one very slightly overlapping the end so it catches and Bob's your aunties toyboy.

I don't think the old just brass unions are available any more. The new ones do have an interference fit - ball into a cup but I think they use the rubber seal as an extra, so not sure if the ball end on the valve would be ok on the old cupped union end, could always try it.

 

[bilabonic]

I just find the the tails keep on screwing on the way in?
I’ve tried with PTFE and still get weeping joints.
Never tried adding paste as well though.
Plumber I know stated 13 turns.
The threads are so long on tails what part of tail is it best applied. Bit confused on last turn on the end?
Eg. PTFE is no where as wide as tail thread, do you warps it all in on spot on top of each other??

Cheers

 

[Madrab]

GAS PTFE tape is thicker, so less turns are required. I use gas tape all the time, no paste needed and it's what I have to hand to hand, I use 7 full turns.

Do note though I could keep turning the tail until it was all the way in but that's not needed, it's a feel thing. The tail will tighten up enough at about 1/2 of the way and I will keep tightening it until around 2 threads are still showing, never had an issue with leakage. Make sure the tape is wrapped in the same direction when the thread is running downwards towards the valve end of the tail, so it doesn't want to unravel as it's tightened into the tapping, overlap one of the turns slightly over the edge of the tail.

 

[bilabonic]

I have some yellow gas tape.
Never new it was thicker tbh, plus I always wrap correctly with thread.

What I did find today on a window cill was this below.
Is this not the ‘part’ that actually holds the inner ‘valve’ in place?
Has it somehow been removed by someone trying to just open the lock shield?
The boiler has zero pressure and it seems to much of a coincidence.
I placed it on top of the shield just for pics BUT should it push the valve back in place ??
I did apply light pressure just manually/fingers ams could not see how it would bite/catch a thread.
If so this could just be a simple fix once reseated.
Thanks once again.

 

[terryplumb]

Possibly it is. Close the valve fully clockwise whilst pushing downward. Then see if the white bush can be pushed down,if it does and reveals a thread ,try screwing the part you found into it.

 

[bilabonic]

So the white bush part is not threaded?
It it actually held in place by the brass bush I found?
It seems way to much of a coincidence to find it with valve covers.
I’ll check another old existing valve later and compare it.

Cheers

 

[terryplumb]

Worth a try

 

[Madrab]

looks like the nylon gland packer, it would normally push all the way home down inside the valve and then the gland nut tightens down to hold it all in place. You need to be careful as that looks like the valve internals might just pull right out of there if you loosen it too much.

 

[bilabonic]

There’s no pressure there anyway.
Only got HW.
So the gland just pushes in and nut holds it?
Want I do t get it that it’s has 1.5/2bar in it like that and was o my a very slight weep.

I checked other rads lock shields and the nut definitely goes in there.
I’ll have a play tomorrow if I get chance.

Cheers

 

[Madrab]

Basically you need to get the nut on and press down as you tighten, hopefully it will catch the threads and as the nut tightens it'll push that packer back down. Have the valve stem tightened down as if the valve was off. Don't over tighten the gland nut otherwise the valve stem wont turn.

If it's a sealed system then ~ 1.2 bar is more than enough, no need for any more than that, certainly not 2 bar.