Humming or buzzing noise in the loft?

[robster10]

Please can someone help me! I have a really loud humming/buzzing noise coming from up in the loft, where my water tank is.
I purposely haven't had my heating on or used much hot water for a few days but still the noise randomly starts up.It seems to be worse after a shower, when I've done some washing or flushed the toilet.I have a Combi boiler if this is relevant.
Any ideas what is causing this & any remedies please? It's nearly 4am & the noise is now driving me crazy! Any help or advice would be greatly appreciated! Thank you

 

[Harry Bloomfield]

Try going up into the loft to locate the source of the noise, seems to be the obvious answer?

Why do have you a water tank in the loft, with a combi? The tank fill float valve is a common source of such noises.

 

[denso13]

Turn the water off to any storage/expansion cisterns in the loft overnight and see if it stops.

 

[robster10]

Try going up into the loft to locate the source of the noise, seems to be the obvious answer?

Why do have you a water tank in the loft, with a combi? The tank fill float valve is a common source of such noises.

 

[Nige F]

Combi or Condensing ? Do you have a hot water cylinder ?