Gate Valves

[Spr0cket]

Hopefully a simple question for the knowledgeable ...

Our property is around 15 years old and the feeds from loft storage tank for cold and also the feed to hot water tank, can each be isolated via gate valves in the airing cupboard.

Whilst fitting some new taps over weekend, it became apparent one of the valves (storage tank feed to hot tank) is not closing fully. I think limescale or crud build up in gate part as extremely tight to turn. To be honest for sake of a few quid, I'll simply replace rather than try and clean etc, but my question is - does it need to be a gate valve same as currently fitted, for such an application.
Would a simple 22mm ball valve be sufficient - one with a throw handle that would allow fully open to fully closed in a 90 degree throw. Does one offer better flow etc. than the other - I'm sure there's a valid reason why one valve has better uses and applications than the other so please educate me.

Not sure if I have correct names for valves I am mentally picturing - though hope it makes sense.

 

[doitall]

Add a 1/4 turn full flow leverball valve.

 

[Spr0cket]

That's what I was hoping you'd say
So why would these have not been fitted originally?

 

[doitall]

That's what I was hoping you'd say
So why would these have not been fitted originally?

Probably not made

 

[seco services]

alot of people still fit gate valves

 

[JPC]

some times like for like is easier cos of the fittings/gap etc being the same.

I must admit even in houyses where i have fitted them where there has not been one i fitted a gate v. ...dunno why just habit.

the 1/4 turn ball valves seem good ( Full bore ) ..fitted one at a shop eto feed a coffee machine ..worked great

 

[easyflow]

Gate valve use is for low pressure ie draw off from storage tanks, and stop cocks, ballafix, 1/4 turns are for high pressure (mains supply).

 

[seco services]

thats not what we where talking about.

 

[doitall]

Gate valve use is for low pressure ie draw off from storage tanks, and stop cocks, ballafix, 1/4 turns are for high pressure (mains supply).

1/4 turns are for isolating anything, water high or low and gas or air.

Gate valves are rubbish and very seldom hold off 100%, unless you install the top quality jobbies.

 

[easyflow]

Gate valve use is for low pressure ie draw off from storage tanks, and stop cocks, ballafix, 1/4 turns are for high pressure (mains supply).

1/4 turns are for isolating anything, water high or low and gas or air.

Gate valves are rubbish and very seldom hold off 100%, unless you install the top quality jobbies.

Yes they are rubbish I agree 100%
Its just what the manufactures quote...

 

[Spr0cket]

Thanks for the input guys.

So from everything mentioned, pro's and cons, there appear no drawbacks to a ball type valve, aside from any potential complications that it may introduce due to different lengths between exisiting and replacement valve.

Right, will try to track down a full bore version tomorrow.

 

[doitall]

BSS and PTS are both in your area.

I would leave the old one in

 

[Softus]

there appear no drawbacks to a ball type valve

Not quite that simple: a spherical valve is capable of being fully opened very quickly. Sometimes this isn't a good thing, because of the mildly explosive force of a sudden flow of water/steam/gas filling previously empty pipework. In extreme cases fittings and components can be stressed beyond their design limits.

This can be mitigated by taking care when opening a spherical valve, but the sudden can also happen inadvertently, because the lever is so easily knocked, unlike a gate valve.

Gate valves have the advantage of making it impossible for this scenario to arise.

Cheap gate valves are a curse, because they seize up and/or fail to shut off.

Cheap ball-o-fix valves are a pain because they seize up and/or leak from the gland.

 

[doitall]

You wouldn't use normal gate valves on high pressure

 

[Spr0cket]

Softus, good items for consideration - thank you.

I'd consider due to application (gravity feed from loft) that a ball would work OK - and to be honest - I wouldn't know a good brand of gate valve vs a bad one.