Pump works, briefly, then gets quieter, doesn't pump
When I start to pull a shot, everything sounds normal, works normally. Then the pump gets very quiet and stops pushing water through the coffee. To me it seems as if a valve gets shut, but the pump is still trying to pump. If I turn it off, then on again, it works briefly, then gets backed up (or loses pressure?) again.
It works fine without the Portafilter in place. It works with an empty PF - but it leaks out the top so much that the pump isn't really being challenged.
All screens are clean, and I've tried single shot pods (my norm) and double shot with Starbucks ground espresso, loosely tamped.
Thanks for your help!!
Is this a good question?