Thank you! You were spot on about the vacuum breaker. Seems to be fine after cleaning.
-Brew path has no scale, dispersion plate is brand new.
-Since the boiler doesn't overfill even after I use the machine for a while, I decided not to touch the autofill valve for the fear of introducing leaks.
-I got a Joe Frex pressure gauge that I screwed on the second portafilter. It reads correctly on my other machine.
-Unfortunately the machine doesn't have a pump pressure gauge.

I have a feeling that the computer senses no flow against the portafilter gauge and limits motor power. I've seen the pressure build up to 9 bar, when I introduce leaks and the water flows for a bit. I think I am worrying about nothing...

1. It seems you need a new vacuum breaker. You can aleays try to soak it in descaling solution or water and vinegar. These are serviceable parts.

2. This one is a little trickier. A few possibilities:

- There is potential scale in your brew path.
- Did you fully clean the dispersion plate, dispersion hole and top of the group?
- The group or autofill solenoid valve maybe be partially blocked with a loose debris.
- What kind of PF pressure gauge did you build? Did you try it on another machine to make sure it gives a proper read?
- How's your Astra pump pressure gauge behaving when A. Pulling shots? B. Backflushing with a blind filter?
- You may already so this but I would only use the manual brew button when troubleshooting.

I doubt it's the electronic board that's faulty here.

Btw, I'm currently rebuilding the same machine...


Cheers!

Thank you! You were spot on about the vacuum breaker. Seems to be fine after cleaning.
-Brew path has no scale, dispersion plate is brand new.
-Since the boiler doesn't overfill even after I use the machine for a while, I decided not to touch the autofill valve for the fear of introducing leaks.
-I got a Joe Frex pressure gauge that I screwed on the second portafilter. It reads correctly on my other machine.
-Unfortunately the machine doesn't have a pump pressure gauge.

I have a feeling that the computer senses no flow against the portafilter gauge and limits motor power. I've seen the pressure build up to 9 bar, when I introduce leaks and the water flows for a bit. I think I am worrying about nothing...