Hey all, I’m a Starbucks lead at a licensed store and I’ve been having trouble finding out what’s going on with my espresso machine. Everything works as normal, but when the espresso machine does an internal rinse, it makes this horrible screeching noise. My DM has heard it, and told me not to worry about it, but it has increasingly becoming louder, and it is very irritating. Does anybody have any insight on how I can fix this problem or what it might be?

I have taken apart and cleaned espresso machine multiple times, and it does not seem to fix anything. The machine is also fully calibrated.

Thanks in advance.