Lockshield valve leaking

[andy1983]

was rebalancing my radiators by adjusting the lockshield valve. This seemed to work, however, unfortunately I now have a small leak coming from the hole in the lockshield value (where I inserted the allen key). It looks like the water is coming from the side, then pooling in the hole before overflowing. The leak is quite slow, but needs to be fixed.

Am I correct in thinking I can try tightening the packing nut (and if so if this is the hexagonal nut around the outside) and that this can be done without draining the system or doing anything else?

The valves are Fairport Angled Traditional Thermostatic RadiatorValves - Chrome purchased from Victoria Plumbing . They don't seem to offer this type anymore though it looks like they're https://www.victorianplumbing.co.uk...d410f-1034-4f91-89ac-8b0d2e732a77-9DAF9:en-GB these but under a different name.

Thanks in advance

 

[terryplumb]

No ,the hex nut isn't a packing/ gland nut.
The spindle ( Allen key ended) has O ring seals. You would need to drain the system to a point lower than the rad you work on ,to strip the valve down and repair.

 

[andy1983]

Thanks @terryplumb , sounds like I may need to get a plumber. Just to check I fully understand. I have a Valiant Combi boiler, I would need to drain the whole system, then remove the valve by turning the hex nut, this should expose an O ring, which I should replace with a new one, before replacing the valve and repressurising?

 

[terryplumb]

Pretty much correct,but there may be more than one O ring. And inhibitor needs to be added into the system before filling back up.

 

[oldbuffer]

1. You can try tightening the outer hexagonal nut to see if it stops the weep. No need to drain the system or do anything else.
2. However, if the valve is sealed with one or more O rings, the only solution would be to change the O rings. You might as well change the valve as the O rings.
3. In theory you ought to be able to create a partial vacuum in the system and avoid a drain down:
3.1 Turn off the boiler.

3.2 If you have a sealed system (no feed and expansion tank in loft):
3.2a Bleed the system pressure off via a radiator bleed point.
3.2b Make sure any automatic air bleed valves are closed (little brass bottle with a Schraeder valve cap on top. Close the cap)
3.2c Close both radiator valves. Count the number of 1/8 turns of the lock shield so you may be able to maintain system balance on completion.
3.2d Plenty of old towels down
3.2e Gently open the valve to radiator nut of the lock-shield, slacken the bleed valve, and drain the radiator contents into a tray. Make sure all floor coverings are protected.
3.2f Slowly undo pipework to valve nut. Be prepared for a bucketful of water. If it doesn't stop after this, abandon attempt as there is a leak (of air) somewhere on the system. If this happens, re-tighten nuts and close bleed valve.
3.2g Fit new valve. Tighten nuts, close bleed valve, re-open lock-shield recorded number of 1/8 turns.
3.2h Re-pressurise system.

3.3 If you have an open vented system:
3.3a "Bung" the feed and vent pipes of the F&E tank so that no air can enter the system,
3.3b Proceed as 3.2b to 3.2g
3.3c Refill the system