PeanutBuddha wrote: Additionally. I adjusted the pressure by turning the nut (pointed to in picture). Any idea what the red valve to the left does?

Turning that red valve 90 degrees clockwise will close/stop the flow of water from going through the slim OPV valve. The big OPV valve will now be completly responsible for the brew pressure. If you run the pump with a blind disk you will see that the brew pressure gauge will be higher than the 9.75 you set it at just now. Basically the only reason to close that valve is to adjust the big OPV. Once the big OPV is set then the red valve should be positioned in the open position(Like it is in your photo).

By the way just to make sure we are talking about the same thing. The slim valve is what you are pointing at with the screw driver + that red on/off ball valve. The big OPV is to the right and can't really be seen in your photo since it is under the water tank.

Hm, I fiddled with the slim OPV (red highlight in photo) in order to achieve the higher desired pressure. Was this incorrect?
I believe we are on the same page. Although I am having difficulty understanding how the two OPV valves correspond to each other and the function of the larger OPV (green highlight).

From what I gathered the larger OPV / expansion valve functions to set a limit on the internal brew / idle pressure. In other words, it controls the built up pressure inside the machine when its not actively pulling shots, etc. And if the red valve is in the off position it will only pull to the set max when using a blind filter (for idle pressure setting purposes).

Thanks again for your input. You have been a big help and I appreciate your time.

The slim OPV with the red valve in the same position as in your photo is what you are supposed to adjust in order to achieve your desired brew pressure. You did this correctly.

I think your reasoning for the big OPV is correct, but I am not 100% sure. All I know is that it should be set to a limit higher than what the slim OPV is set at. For example 10, 11 or 12bars. In order to adjust that big OPV you would need to rotate the red valve 90 degrees clockwise and once you are done then turn it 90 degrees counterclockwise. A while ago I sent Rocket an email asking about how to go about adjusting the OPVs. They said to just set the big OPV at 12bar and the slim OPV at 9bar. Mine is currently set at 12bar and 10bar respectively.

Awesome.
Thanks again for your help.