Miller Pneumatic Valve - Ryko Bi-Folds

[Bubbles Galore]

I am having issues with one of my valves for my Ryko Bi-Fold doors. I'm not sure if it's the 3 way valve or the feed line solenoid that opens to close the doors. I think I can get the feed line solenoid fairly easily, but I'm having issues finding the miller fluid power valve. The specs are as follows:

• Miller Fluid Power Corp.
• Pressure Range 25-240 PSI
• P/N 5251

Does anyone have any ideas where I can source this? Should I call Parker direct and see if they can cross reference the product number? Any and all help is appreciated!