[ToddF]

It violates R77.B:
"The only pneumatic system items permitted on 2014 FRC ROBOTS include the items listed below. ...
B: Pneumatic pressure vent plug valves functionally equivalent to those provided in the KOP."

A momentary push button electrical switch is not functionally equivalent to a toggle switch, which must be actuated in both directions.

A spring-loaded single-acting pneumatic cylinder is not functionally equivalent to a double acting pneumatic cylinder, as it returns to its retracted position without actuation.

A spring loaded push button pneumatic valve is not functionally equivalent to a rotational ball valve, which must be actuated in both directions. For the purposes of a dump valve in a FIRST robot, the functionality of being spring loaded makes it better than a ball valve. From an air flow perspective, they may flow the same, just as electricity doesn't care whether it is switched by flipping a switch or pushing a button. But, to the operator, they are very different. If it were functionally equivalent, there would be no reason to use it. (Other than cost and availability.)

I suggest a question to Q/A. I'd love for them to rule the push button dump valves legal.