Humming sound in system or boiler? Name that tune in one!

[JohnHuson]

Humming noise when hot or cold tap is turned on and I assume it is the boiler but hard to tell as the sound appears to be in the system as a whole. Vokera Unica 28HE about three years old. No problems with it. Pressure is OK. Auto vent is working as it should. No bangs or other noises. No warning codes, working OK. Radiators vented. Stop tap is OK and is open fully but tried it slightly open with no change. No obvious noises coming from within the boiler casing but there is a slight viabration detectable, and as I say the noise may be the boiler but not sure.
Any ideas please?

 

[jtsplumbing]

Water pressure may be to high if so think about getting a pressure reduceing valve fitted on incomeing water main.

 

[diamondgas]

Try turning the boiler off and see if the noise goes away John If it's only when either hot or cold tap is turned on then it's unlikely to have anything at all to do with the boiler IMHO