Noisy cold water tank when filling

[Lower]

I've just fitted a 50 gallon cold water tank in preparation for a fitting a shower pump.

When the tank is filling at full flow there's quite a bit of noise being transmitted back down the cold water pipe and into the bathroom below. The noise goes as soon as the float rises and starts to reduce the flow. The noise wasn't there when the old tank was in use.

The cold water pipework hasn't changed much, the only difference being the new float valve and a 90 degree isolation valve elbow fitted to the ball valve.

The noise is definitely coming from either the float valve or the 90 degree isolating elbow (which is fully open) but can anyone give me a pointer on which is likely to be the culprit.

I can replace the isolating elbow with a standard elbow fairly easily, but wondered if anyone had experience this before and as to whether its likely to be the elbow or the float valve itself?

The float valve came with the 50 gallon water tank kit that i bought from screw fix, as did the isolating elbow , so no idea of brand i'm afraid but i've linked to the kit below:

http://www.screwfix.com/prods/10134...d-Water-Tank-50gal-1190-x-610-x-500mm#reviews

 

[swidders]

What sort of noise?

 

[Lower]

Water rushing through a pipe type noise. It sounds as if the flow is strangled as it gets quieter as soon as the float valve starts to close.

 

[Diyisfun]

Water rushing through a pipe type noise. It sounds as if the flow is strangled as it gets quieter as soon as the float valve starts to close.

That sounds like the sort of noise you want to hear..
Try reducing the flow on the main inlet

 

[Lower]

That's exactly what i don't want to do. I want maximum flow into the tank, but at max flow either the float valve or the service valve is causing a restriction that is making excessive noise.

The old set up didn't make this noise with similar flow rates. I was hoping for some guidance as to whether its the service valve or the float valve.

 

[banditboy]

we have a similar problem,
the feed for the shower is a tee, on the feed for the main tank, about 10 inches from the ballcock,

when running a bath, the noise of water filling the tank,is taken down the shower feed into the bath room [about 6 metres]and the shower case acts as a speaker, with a rushing sound...!!

i assume its the water rushing past the tee,making a sort of resonance on the shower feed...

im not sure there is cure for it......

 

[JohnD]

I am not a plumber

however I once had a similar problem, so I fitted a 3/4" ball valve on a 60/75 gall tank, and it worked well (the supply pipe is 15mm and the noisy ball valve was 1/2")

as it has twice the capacity of a 1/2" one, the water velocity is lower and it is quieter (also fills up a bit quicker due to lack of restriction). You can change the last bit of pipe, and the elbow/service valve and they will be a bit quieter too.

I tried to get a 3/4" Equilibreum Valve which is even quieter, but they are stunningly expensive

 

[steved101]

Good idea John - Equilibrium valves are not normally for use in cold water cisterns, mainly for WC cisterns.

Also, OP have you got the correct orificie in the new ballvalve?

 

[Lower]

The specific issue with this application is that the previous float valve supplied by the same size pipe didn't make this noise.

The only variable in the system is the new float valve and the service valve elbow fitted to the float valve. Its got to be one or the other.

First step is to take out the service valve elbow, then to try fitting the original float valve into the new tank.

 

[steved101]

Try the old valve with the elbow, then you will know if it is the elbow!

Also check you have the smaller orifice in: ball valves come with 2 orifices, 1 for low pressure and 1 for high.

Does the new cistern have a backplate (with the ball valve inserted through it to steady it to the cistern?

 

[Lower]

New cistern does have a backplate and is fitted, but the ball valve didn't come with a spare orifice. Could that be the problem? How would i know if i have the wrong orifice fitted?

Try the old valve with the elbow, then you will know if it is the elbow!

Also check you have the smaller orifice in: ball valves come with 2 orifices, 1 for low pressure and 1 for high.

Does the new cistern have a backplate (with the ball valve inserted through it to steady it to the cistern?

 

[banditboy]

some great ideas there, may have to have a venture up into the loft...

 

[Lower]

I changed the elbow this evening from the service valve elbow to an open elbow.

Unfortunately, no change in the noise.

So its got to be the the float valve.

I could change over to the original, which was quieter. However i'm reluctant to do that because the old one must be 15 years old at minimum. Any ideas what i can do to quieten down the existing? The nozzle appears to be correct as it has the same size aperture as high pressure aperture.

 

[JohnD]

you could fit a Torbeck which would be very quiet but I don't know if they are approved for CWCs.

 

[doitall]

Don't fit a Torbeck it will reduce the flow too much.

An Equilibrium valves will improve matters considerably, as would a full flow lever ball valve.

Fitting a second ballvalve and reducing the pressure would be even better.

Lagging the pipes with 25mm wall lagging will reduce the noise even more.