Help! Central heating/water sounds like it's on but it's not?!

[Ashling]

So in our house you can always tell when the heating or water is on, as there is a dull noise that goes with it. When you switch heating/water off the dull noise stops. However the last 2 days the 'noise' is constantly on? Even though it's just a dull vibration it's driving me CRAZY. The noise is not coming from the boiler, it appears to be coming from hot water tank. We've not touched the tank or changed anything at all so why is this happening? It kept me awake last night just the constant vibrations? Any ideas?

 

[Gas2Air]

Maybe the mystic ones among us could help, who knows?

 

[jeff the gasman]

Maybe your pump is not switching off after a heating demand.

 

[muggles]

Yep, sounds like pump vibration to me, possibly now combined with a sticking zone valve