MediumRoastSteam jhf - When you say “water returning to the tank” - do you mean with a blind filter or making coffee, or while you were measuring the water debit from the group without any portafilter engaged?
MediumRoastSteam jhf - OK. All I want to say is that water should not return to the tank if there’s no built up pressure (i.e.: there’s no portafilter). Water should only return to the tank when the pressure reaches approx. 10 bar. (or whatever you set your expansion valve to)
jhf Descaling with Puly cleaner descaler helped. Water flow is now 210 ml/30 seconds. Thanks to everyone for the advice and DaveC for the instructions 👍
MediumRoastSteam jhf - That’s good. You might want to turn down that expansion valve to 10 bar rather than 11.
jhf Against a blind cup it shows me 10 bars. With a single coffee (9 g) the pressure rises to 11, then drops to 10 and stays there until the end of the shot. Good?
Clodius @MediumRoastSteam I know you’re recommending this according to the theory of pressure being higher on a blind basket vs a coffee puck, but mine match. So it’s a case of trial and error