Rising main to cold water cistern in loft

[Gareth]

My house is about 9 years old and recently there is a problem that's developed. The symptom is:

When the float operated valve of the cold water cistern in the loft opens and closes something causes an awful vibration in the rising main and a humming that resonates throughout the house.

When the float operated valve is wide open the vibration and humming ceases. When the vibration and hum occurs I can minimise it by drawing water from the main, by a tap in the bathroom for example.

I've tried reducing the flow through the main stop valve and service valve to the cistern, but the vibration and hum still occurs when the float operated valve is less than 100% open.

Can anyone please suggest a possible cause?

 

[dontknowitall]

Probably the washer in the ball valve (in the cold water cistern). I find it quicker and easier to change the whole thing rather than fiddling around with the washer.

I'll assume you know how to change it but if you're not sure, loads of people on the forum can tell you.

 

[Gareth]

Thanks for your advice. If it is the washer I can change that, or the valve myself. I did wonder if it was the washer. If the problem was only occuring when the float operated valve was sealing I would have gone straight to the washer. It just foxed me how the problem occurs when the valve is open. Time to get in the loft and take a closer look!

 

[Blackcatgas]

Probably the washer in the ball valve (in the cold water cistern). I find it quicker and easier to change the whole thing rather than fiddling around with the washer.

I'll assume you know how to change it but if you're not sure, loads of people on the forum can tell you.

+1 and if that doesnt work fit a soix cheif mini airester.

 

[Gareth]

Thanks for that suggestion, I used to work for a manufacturer of industrial valves and I wondered if it was water hammer, but as the system had been fine I didn't consider it further.

Anyway when I went back to the loft to check the washer I found I didn't have the right tools to get the cap off and while trying to get the cap off I rotated the valve body. This meant I had to rotate it the opposite way so the arm fell vertically.

I don't know if the arm not falling vertically can be a cause of the problem, but now I've realigned it the problem has gone!

The washer is sealing fine so if the problem recurs and the valve is okay I'll check out the soix cheif mini airester.

 

[Blackcatgas]

Thanks for that suggestion, I used to work for a manufacturer of industrial valves and I wondered if it was water hammer, but as the system had been fine I didn't consider it further.

Anyway when I went back to the loft to check the washer I found I didn't have the right tools to get the cap off and while trying to get the cap off I rotated the valve body. This meant I had to rotate it the opposite way so the arm fell vertically.

I don't know if the arm not falling vertically can be a cause of the problem, but now I've realigned it the problem has gone!

The washer is sealing fine so if the problem recurs and the valve is okay I'll check out the soix cheif mini airester.

Iam not sure if Ive spelt the name of the device correctly Gareth but google it and it should come up with the goods.

 

[WHPES]

It should be "sioux chief mini arrestor." 3 typos - you had no chance of finding it on Google.

Sioux Chief

UK distributor - [DLMURL="http://www.masefield-epson.co.uk/plumbing-products/sioux-chief-water-hammer-arresters-waterfoil-central-heating-protector.html"]Masefield-Epson | Sioux chief water hammer arresters / Waterfoil central heating protector[/DLMURL]


Everybody posting descriptions on site PLEASE take the trouble to make sure you have the correct spelling or it is as good as not posting at all!

However I doubt it will actually solve your problem. The arrestor is to stop water hammer whereas you have a vibrating system. A section of pipe will be acting like a piano string when activated. Sometimes you can put your finger on the pipe when it is doing it and locate the offending piece. Try adding extra brackets. Otherwise something as simple as a piece of rag tied round it can alter the harmonics and stop the problem.

 

[Blackcatgas]

It should be "sioux chief mini arrestor." 3 typos - you had no chance of finding it on Google.

Sioux Chief

UK distributor - [DLMURL="http://www.masefield-epson.co.uk/plumbing-products/sioux-chief-water-hammer-arresters-waterfoil-central-heating-protector.html"]Masefield-Epson | Sioux chief water hammer arresters / Waterfoil central heating protector[/DLMURL]


Everybody posting descriptions on site PLEASE take the trouble to make sure you have the correct spelling or it is as good as not posting at all!

Sorry Mum!