I've created an arduino code to switch on and off the solenoid (a modified blink.io code). Right now the board outputs a maximum of 12V, and my Solenoid is 24V so isn't operable by the board. I tested the board on a smaller solenoid, though, and it started opening and closing! I tried wiring two of the arduino shield's output ports in series, but the voltage remained at 12V.

Next steps are to order a 12V solenoid and a pressure sensor, so that the solenoid can be autonomously opened or closed by the arduino depending on the pressure in the chamber. I plan to use a DigiVac Model 276 (BASE) vacuum gauge which includes  a thermocouple vacuum gauge combined with a piezo sensor. Any insights on creating an arduino code for operating this system would be appreciated!