Noise from cold tank in loft

[poets2904]

When I run the kitchen tap or the upstairs shower I get a high pitched whining noise for a few seconds from the cold water tank.I thought it was the floating valve in the cold tank so changed it but it doesn't seem to have helped.Any ideas from anyone please??

[essexshazza]

it could either be an air lock or the pressure of the water coming through the valve in which case try changing the washer on the ball valve in the tank, or you could try opening all your cold water fed taps (except drinking water) and turn them off from the lowest point leading up to the tank if none of these work then i really dont know what to suggest.