Hi – THIS MACHINE FILLS UP BUT THEN BUZZES FROM THE VALVE AND WON’T ADVANCE. Advance it by hand it works fine. SO WHY AFTER IT INITIALLY FILLS UP DOES IT STOP AND THE VALVE BUZZES AS IF IT WANTS MORE WATER ?? i’ve bled the pipe from it and checked things over but all I can see is the valve safety part may be faulty ?? ANY IDEA’S 🙁