Isolating valves. How reliable????

[matz]

Just a quick question about isolating valves. In our airing cupboard theres a valve dircetly either side of the CH pump. When you close these valves off, water is still getting into the pump so the valves don't appear to be working.

On the hot and cold feed to the gravity fed shower, again, there is a valve on each one but turning them off doesn't stop the hot and cold going into the shower! (these valves are about 24" from the shower and I've let the shower run to empty the pipes)

The valves in question have a brass body and a red metal wheel tap sort of thing. I'm not sure if isolating valves are the correct name for them, anyway, I've read in the past that these are notoriously unreliable.

Is it possible that I'm getting 4 valves that are'nt working properly here? What sort of life do they have? I'm pretty sure they're about 12 years old and they seem to turning reasonably freely.

 

[ollski]

The valves with the handles are normally pretty good though they sometimes leak from the spindle and just need a bit of a tighten up....as a general rule of thumb if its an isolating valve operated by a screwdriver I never touch it, but if it generally looks a bit weedy I don't touch it either, its usually beter to either drain down part of the systen or bung it, I mean if your pump is upstairs in the airing cupborad you don't need to drain down very far.

 

[ChrisR]

Gate valves, if they have "wheel" heads. Horrid things. The ones on the pump may be quarter turn ball type, which are even worse.

Buying better makes like Conex or Pegler sometimes gives you a better quality product, but not much.

Full flow lever operated valves are the current favourites, whether they'll prove to be any better long term is still open.

These valves are typical of many plumbing products - cheap rubbish.

 

[matz]

ok thanks for the comments. So, it's likely that I have 4 valves that are all stuck part of full open as turning the ones I mentioned off make NO difference to the water flow!

 

[ChrisR]

That's about it. If you turn the gate valves off really hard (plumbers' arms are sufficient, you don't need to use a spanner, god forbid), you jam the wedge of brass so when you undo it again the shaft snaps off or the threads strip...

These are one choice for replacement, see Pegler Brassware at screwfix:

 

[chrishutt]

Matz, I think if you're having no result with all four valves, you're doing something wrong. Gate valves need to be turned fully clockwise to shut. May be something like 5 complete turns. The last quarter turn is quite critical (deposits in valve will obstruct closing) so best to shut, then open slightly, then shut again, etc., until valve seals.

 

[matz]

Matz, I think if you're having no result with all four valves, you're doing something wrong. Gate valves need to be turned fully clockwise to shut. May be something like 5 complete turns. The last quarter turn is quite critical (deposits in valve will obstruct closing) so best to shut, then open slightly, then shut again, etc., until valve seals.

I've just had another look at the shower gate valves and have opened and closed them carefully several times, making sure they are fully tight shut (clockwise) When fully tight shut the water coming from the shower is reduced but no where near stopped. Opening that valve increases that shower water flow very slightly. What a pain, looks like I've got to replace all the valves. Thanks for the pic ChrisR.

 

[ollski]

why do you need to change the valves?, they are generally only there to aid component replacement or repair so if they are knakered wouldn't it be easier just to replace them when the time comes?

 

[chrishutt]

the water coming from the shower is reduced but no where near stopped.

Could be you've got gate valves on mains pressure? Gate valves are only intended for low pressures.

 

[matz]

Don't think so, the hot feed comes straight from the hot water cylinder and the cold comes down from the loft.

I want to isolate the shower as thats not working properly either

 

[MeMyselfAndI]

Why are we isolating the heating pump to turn of the shower

 

[matz]

Why are we isolating the heating pump to turn of the shower

We're not. I flexed a joint on the CH pump which leaked whilst accessing the fuse box for the immersion element that I wanted to change. I mentioned the gate valves as I wanted to access the shower that appeared to have given up the ghost at the same time.