Most of the heavies use normaly closed valves , You need to give them power to open.

In your case, you need power to close them, making it a rather dangerous setup. Link up, hope the valves that need to be closed are powered (LED is your friend here), before you open the bottles, very very gently -turn knob valves, not fire-extinguisher handles- And if during combat the power fails, your weapon will be activated, but blowing CO2 right out of the exhaust valve too. White clouds anybody?

Modifying a Burkert. It's probably easy enough, but I myself never had the chance to look into a normaly open Burkert 5404 with 12V solenoid. Where did you order it?