My Gaggia has stopped working. when I turn it on I get a low water indicator. In the past I was able to fix this by repairing the little float sensor in the water tank by adding some cork to the top of it. I tried the same fix this time but it still is indicating low water level. Not sure how to fix this. Is there a way that I need to prime the pump? Otherwise the thing is basically a boat anchor. Help would be appreciated.