When extracting a 25/30ml shot, the adjustable one way valve - opv - down the bottom over the tray throws out about 150ml of water during the shot. Is this excessive or do I need to adjust the valve - at the risk of stuffing up group head pressure? No complaints about shot quality or extraction times.

It's been like this since I acquired the machine - nearly two months. It's an E98 S1, about 4 years old and pulled no more than 20 or so coffees before I got it. It's been thoroughly cleaned and descaled.

I have the same machine, and the OPV lets out quite a lot of water during extraction. I think it's normal. Have you checked your brewhead pressure?

I don't have a gauge - yet. But your answer is reassuring.

Thanks