[FuriousGeorge]

I'm currently working with simulations on Hysys V8.0 and i keep getting this error: "flow rate, pressure drop and opening should be non zero. Unable to size valve..."
This valve connects the steam output for a CSTR reactor, problem is due the simulation is in dynamic state i can't modify the values for the steam line because hysys won't let me.

Is there any steps i'm missing to be able to modify any value?
 
Thanks in advance.