you have an airlock in the valve. you need to turn off water and disconnect hose , remove plate from valve connecter and you will see a bleed off clear hose with a small white plug in end, bleed off water and then reassemble. start machine on rinse cycle without turning on mains water ,when you hear buzzing sound turn water on. hopefully problem solved.
these machines have always had problem with iwms water meter tank.( ex zanussi engineer)
david osgood
March 2005