The S1 Cafe - Helping Your Espresso Dreams Become Reality

I picked up a used S1 Vivaldi II and I'm getting little to no flow in the grouphead. Machine is dated 2011, not maintained well - but at least ran on a reverse-osmosis filter system.

I don't have a timer installed yet so I have that switch set to "OFF"
I can hear the solenoid click when I start a shot
I can see/hear the pump motor kick on
Sometimes there will be some flow during pre-infusion stage, and then it will stop when the shot is being pulled (no portafilter)
Yesterday I was getting some pressure shown on the group gauge when it was heating up, up to 12 bars, down to 5, up to 12, down to 1
Steam boiler seems to be working fine
I tried a blank portafilter disc and was not able to build pressure/nothing coming out of the OPV
I've tried on two different 5-gal pumps

Any ideas? I'm assuming something could be clogged, but I'm not sure where to start.

*UPDATE*
I pulled out the solenoid valve and the grouphead, took everything apart and soaked/scrubbed with cafiza. Still not getting much/any flow out, however the pressure gauge is showing a steady line pressure of about 2-3psi, so that did clear something out. Given that I can hear/see the pump MOTOR kick on, but see no jump in pressure, could that mean that the pump is shot?

Seeing a very similar issue on my vivaldi ii... did you ever resolve this?

I am not sure why I answered as if you had a Mini when your post is clearly about a plumbed in VII. Ignore my previous post.

Did you mean that you are seeing 2-3 bar rather than 2-3 PSI. 2-3 bars is OK as you should see the water line pressure when the pump in not running.

As for whether the pump has failed, does it seem to work on the steam boiler? Try pulling 3-4 cups via the hot water spigot and see if the pump comes on a refills the steam boiler OK. If so, then the pump is OK.

When you try to pull a shot does the group water come out of the 3-way valve pipe into the Drip Tray. If so, then the 3 way valve is stuck open. If not then the 3-way valve may have failed. Do you here it click when you press the shot button? If not, you should probably order a new 3-way solenoid valve.

I have had that valve fail a few times on my machine. Enough times that I have created a test cable with a 110 plug on one end, some zip cable, then some of the push on connectors that fit onto the 3-way solenoid when the regular cable is disconnected. In the US, 110VAC solenoids are used so I can just plug them into a 110V outlet briefly to see if the solenoid opens and closes OK. If it doesn't, then the solenoid is bad.