It eventually returned to normal. The check valve may not have been primed properly (trapped air bubble).

Did you disassemble your pump to check to see if any parts were broken? Also, how old is the pump? If it's 2 or more years old, I would just replace the pump and check valve for good measure, it's about $50 in parts + shipping from CC (Chris Coffee).

My Anita is pulling about a dozen or more shots a day in the startup office that I work at in San Francisco, so it's definitely being taken through the ringer.

If it worked a bit after cleaning, then didn't, I wonder if there is some sediment or mineral bits in the water being used causing the problem? A particulate filter on the intake line may be in order.

Thanks for the reply I did not disassemble the pump yet. I may just start by removing the check valve and soak it in vinegar see if it helps. If not I'll probably just replace the pump, not sure if I have the time to take it apart for now....

The machine is a 2009 serial number but bought it used about 2 years ago.

Mine can be fine for a day or two and start doing the up and down noise during a shot (and silent with blank) only after the second shot in a row or only after the machine has been on for the whole day.....or even on the But I've noticed that if I leave it off for a couple of days, it's usually fine when I use it again, but will fail again a some point in the day or the day after....