Leaking manifold isolation valve

[Milleniumaire]

In late 2020 an Omnie underfloor heating manifold was installed for our bathroom. It was installed in the bottom of a wardrobe in the bedroom next to the bathroom. A few years later all the carpet and the chipboard flooring in the bottom of the wardrobe was soaking wet due to the automatic air vent leaking water over a period of time.

Yesterday I needed to drain down the system to replace some radiators and decided to isolate the Omnie manifold using the two isolation valves that came with the UFH kit. As soon as the red (supply) valve was turned off (horizontal) it immediately started leaking, dripping water constantly. I immediately closed it again the dripping stopped, but I believe small amounts of water are still seeping out of it. The leak is from the base of the red knob, not the connections to the manifold or pipe. On closing the blue (return) valve I also noticed a small amount of water seeping, but not as bad as the other valve. The system has been drained now, so in their opened positions there is no leak, but I'm concerned that when I refill the system water will continue to seep out, even if slowly.

Given these valves have probably been used only once before yesterday, why would they leak like this?

Is there anything I can do to fix them or do they have to be replaced?

Is this just poor quality fittings supplied by Omnie or are all manifold isolation valves this bad?

I believe the brand is Emmeti, at least it was for the automatic air vent that was replaced under warranty by Omnie and as you can see in the photo below, it appears that the manifold was made in Italy.

 

[endecotp]

Yes, isolation valves are notorious for leaking if you ever turn them.

Reputable brands (£££) might be better.

 

[Milleniumaire]

Yes, isolation valves are notorious for leaking if you ever turn them.

Reputable brands (£££) might be better.

Which brand produces a manifold isolation valve that does what it is supposed to do without leaking?

 

[Gasguru]

Remove the nut and handle....if you're very lucky you might find a gland nut you can tighten down to seal the stem leak.
Pretty much all plumbing fixtures are poor quality...and UF heating manifolds often have 100s of potential leak points.

 

[Milleniumaire]

Remove the nut and handle....if you're very lucky you might find a gland nut you can tighten down to seal the stem leak.
Pretty much all plumbing fixtures are poor quality...and UF heating manifolds often have 100s of potential leak points.

Thanks Gasguru, I did remove the handle, unfortunately it is designed without a packing gland nut, so I'm unable to do anything with it and it will need to be replaced. Cheap, crap Emmeti, just like all the other parts on this Omnie manifold.

If I'm going to the effort of replacing them I would like to chose a brand that at least has a chance of not failing when I eventually need to isolate.