Intermittent humming mains pipe

[Turpin]

Hi,

We have an odd problem that only occurs when the weather is cold and goes away when the weather gets warmer.

When we run the hot or cold (off the tank(s) not direct from mains) we get a hum from the Mains pipe after a few seconds - if we turn on a downstairs tap that is directly fed from the mains, the hum stops.

The hum stops when the tank has refilled. If I run the Mains feed cold and a tank hot/cold tap at the same time we get no hum.

Turning the stopcock down quite a way or completely off stops the hum.

What would cause this in cold weather only ?

 

[Breesey]

Dunno about the weather but if you change the cistern ball valve I reckon you will stop humming!!

 

[bab]

its a dint in the ballvalve washer thats causing this type of water hammer, very common in part 2 type diaphram valves . A new washer will cure it but if its a few years old the the orifice if plastic could be rough so a new valve can be the best option.