15mm water isolator problem

[blackrose]

I have an issue that appeared simple but has now got me stumped.

 

I tried to isolate the water supply to my gas water heater using the 15mm isolator with the small plastic lever. As soon as I turned the handle to isolate it, it started leaking through what appeared to be the lever connection. So I replaced the isolator with one I happened to have onboard which doesn't have a lever and it's operated with a flat screwdriver. 

 

So far so good. Turned the water pump back on and no leaks. The new isolator happened to be in the open position but when I tried to turn it closed it started spraying water everywhere through the open/close mechanism  (ie. the same place where the lever was on the other one).

 

Does anyone know what's going on?

 

If I try to close the new isolator it will spray water everywhere. No leaks if it's left in the open position.

 

 

 

[MoominPapa]

I'll take a guess that they're directional, and not intended to have high pressure on the side the arrow is pointing _towards_ when closed. I'll take a further guess that you have a calorifier which you use when the gas heater is isolated, so that there is pressure on that side of the valve, when closed, from the pressure in the calorifier and hot pipes coming back through the heat-exchanger. If I guessed right, I use half-turn butterfly-handle valves for the same function and have had no such problems.

 

MP.

[Tony Brooks]

I think that you are correct, well spotted

 

Edited December 10, 2021 by Tony Brooks

[blackrose]

It's a directional isolator, but it's installed the correct way around with the arrow pointing towards the heater.

 

There is a calorifier but it's on a separate cold water feed.

Edited December 10, 2021 by blackrose

[blackrose]

I'll see if I can buy a non-directional isolator

[MoominPapa]

1 hour ago, blackrose said:

It's a directional isolator, but it's installed the correct way around with the arrow pointing towards the heater.

 

There is a calorifier but it's on a separate cold water feed.

But if the outlet from the calorifier and the outlet from the heater are connected together, then the outlet of the heater will be pressurised. There's nothing in the heater to stop reverse flow, so the inlet to the heater will be pressurised too, as will the outlet side of the isolator, where the arrow is pointing. The arrow is there to tell you not to pressurise the outlet side when the isolator is off.

 

https://www.ebay.co.uk/itm/271605613643?hash=item3f3cf4c44b:g:LwsAAOxyA7tSYOui

 is what you need.

 

MP.

 

[pete.i]

They are also a pile of junk. I have them all over my house and most are leaking to one extent or another from the same place. They are a ball valve which really doesn't like pressure of any sort after a while. They are useful in a boat where space is at a premium especially with water pipes etc that tend to to be laid in extremely tight areas. I'm replacing all the ones in my home with gate valves where I can. Unfortunately gate valves tend to be a lot bigger with a great  big turning thingy on them, I will, probably, have to keep one or two of the ball type isolators due to space constraints but we shall see.

[phantom_iv]

Gate valves are a pain. 

7 minutes ago, pete.i said:

 Unfortunately gate valves tend to be a lot bigger with a great  big turning thingy on them, I will, probably, have to keep one or two of the ball type isolators due to space constraints but we shall see.

 

I have to say I hate gate valves even more. They tend to stick after a while if you're not very careful of them, and they seem quite leaky even from new (maybe I've been unlucky). Would rather have a decent ball valve such at this type - https://www.screwfix.com/p/lever-ball-valve-red-15mm/67744 , or indeed one like MP suggested above if space is at a premuim - I find the lever ones easier to operate if there's space though

[blackrose]

2 hours ago, MoominPapa said:

But if the outlet from the calorifier and the outlet from the heater are connected together, then the outlet of the heater will be pressurised. There's nothing in the heater to stop reverse flow, so the inlet to the heater will be pressurised too, as will the outlet side of the isolator, where the arrow is pointing. The arrow is there to tell you not to pressurise the outlet side when the isolator is off.

 

https://www.ebay.co.uk/itm/271605613643?hash=item3f3cf4c44b:g:LwsAAOxyA7tSYOui

 is what you need.

 

MP.

 

 

 

The outlets from the calorifier and the gas water heater aren't connected together. There's an L-port valve between the two outlets which means only one supply can be used at any one time and prevents any connection between the two.

Edited December 10, 2021 by blackrose

[Feeby100]

The pressure got noting to do with it the The ball valve coupling is designed for mains water so that is far stronger than any other hot water pressure

 

[David Mack]

Had the same problem with this type of valve fitted to our fan convector radiators at home. Fine as long as you leave them alone, but leak horribly if disturbed. And then you have rusty stains down the pipework and soggy carpets until they seal up again (which they mostly do). I replaced all mine when I had the system drained down, and so far so good, but I expect the problem will recur in time.

[jonesthenuke]

I am afraid you get what you pay for.

 

Ball valves have become very common due to low price, small size etc etc. Many ball valves are made as cheaply as possible and in consequence they are not without problems. I have had several leak from the stem seal following use once they have been left in one position for a long time (generally years). These were of the lever handle "better" ones as supplied by Screwfix, see post above. There are valves which have adjustable seals, and thee give tyou a chance of resolving steam leakage but they are more expensive. The valves made by Pegler have a good reputation, but I have not used them enough to warrant a recommendation

 

The traditional gate valves aways had adjustable stem seals and would allow adjustment or even repacking, but it comes with higher cost, greater size etc.

 

[blackrose]

So it's just crap isolators then? I've bought a full bore non-directional type so let's see how that works ..

[jonesthenuke]

The directional issue is irrelevant if the leakage is via the stem. Your new valve will work fine and probably last years.

[Tracy D'arth]

These cheap bulk buy ball valves are poor quality   junk actually. they cost pennies.  They are just about ok as isolator valves that will never get used!  They will actually seal better under higher FORWARD pressure rather than low pressure. Any reverse pressure is a no no.

Look at the cost of good ones like Pegler's and you will see the difference.

[Ex Brummie]

A lever ball valve is always the way to go, or at least a good quality 'butterfly' valve in limited space; Pegler or similar.

Those screwdriver slot types don't like having any down force from the screwdriver as it compresses the lower seal and relieves the top seal, hence the leak. When you think that you can buy a bag of 10 for little more than £5, it gives an indication of the quality.

[blackrose]

1 hour ago, Feeby100 said:

The pressure got noting to do with it the The ball valve coupling is designed for mains water so that is far stronger than any other hot water pressure

 

 

That's what I thought. My water pump pressure is only about 25psi. If these isolators can't handle that they must be really crap.

[blackrose]

Ok I've changed it for the full bore non-directional isolator and it's fine now. Thanks everyone.

Edited December 10, 2021 by blackrose