Ball valves

[Dane Koekoek]

Are there different types of the conventional ball valves?

The reason I ask, is that I recently replaced the ball valve for my parent's cold water tank. I put in a conventional ball valve.

Now, whenever the tank is filling, you can hear a loud noise at the kitchen tap and below the cold tank (where the cold water main obviously runs up the wall). It's as though you can hear the water noise, but amplified.

They never had this before.

I've swapped the little white nozzle inside the mechanism to make sure it's for high pressure (which is was anyway!) and this has made no difference.

Any ideas what I can do to fix this problem?

Dane

[mrcheerful]

they make two sorts of ball valve a 'full bore' type with a big hole, and a standard small hole type. if it is the ball valve making the noise then it is either partially open or undersize.

looking through a good big bore type, the hole is the same size as the pipe, so it is easy to recognise the big bore type, but any plumbers merchant will have them

[TMC]

Tony

[Aidan]

The OP means ball float valves. You're referring to isolating ball valves.

[John Stumbles]

On Wed, 02 Aug 2006 07:28:56 +0000, mrcheerful

I think you're referring to ball-type isolation/servicing valves, the sort of thing you tuurn with a screwdriver (sometimes known as 'Ballofix'), whereas the OP was talking about float valves with a ball on the end of a lever which closes the valve when the cistern is full.

[Dane Koekoek]

The stop-tap has been turned off and on many times over the years, and was set at just before full-on before I touched it, yet this noise has never been heard before, *ever*. Just by changing the ball valve suddenly you can hear it filling at the kitchen tap, whereas you never ever had any noise before. Apart from this noise, the new ball valve works fine.

Any ideas?

Dane

[mrcheerful]

Of course !!! Amazing how I miss the obvious, must be because the problem I described had been encountered by me once.

Best bet to the op is to fit a nice quiet torbeck valve instead. Or turn down the supply a little till it goes quiet.

mrcheerful

[John Rumm]

It is an example of what is called "water hammer". You probably never heard it before due to the flow rate though the old valve being much less than with the new one.

The only way to change it is either swap for another type of valve (Torbek, Siamp, and Fluidmaster are all good examples of float valves that fill quickly and quietly), or to fit an inline service valve[1] before it and to use that to reduce the flow rate to the valve. Hoever note that even reducing the flow rate is not guarenteed to fix it, and you may find you just get the noise from the restrictor valve instead.

[1] actually one task that one of those cheap ans nasty gate valves are quite handy for.

[Guy King]

The message from John Rumm contains these words:

I find Torbeks shut with a bit of a slam. Fine if your plumbing's well attached to the house, but if some lazy git's cut a few corners somewhere you'll know about it.

[<me9]

The Torbeck in our downstairs bog used to bang at times. It was cured by fitting a new washer. However (about 18 months later I think) it has started doing it again. I think it is due to the washer settling in to the closed shape, and thus getting to that state from open quicker, or else the hole in it getting bigger, or a combination of the two.

[John Rumm]

Note that some of these valves come with a spiral "thingy" that you are supposed to stuff up the inlet pipe on them when using high pressure supplies. This helps reduce the noise and flow rate a bit.

[<me9]

It's on a low pressure supply (via a long pipe - so there's a lot of water to stop).

[Guy King]

The message from contains these words:

A couple of right-angled bends just before the valve might help. Certainly hydraulic ram type pumps won't work if the supply's kinked near the pump.

[John Rumm]

How about a couple of pipe clips then?

[<me9]

It's an elbow into the cistern (bottom entry) and an elbow and tee on the wall 3' to the left. The total run must be about 15 metres, mainly 15mm (first half of which is plastic).

[<me9]

It's well supported on the last few metres (where the noise comes from). Thought! eureka??? Washing machine hoses beyond the bog?? Must try with them turned off.