just fitted a bailey dv26 double piston dump valve,run the top hose to the right hand side of the inlet using a t piece ,went out in the car, tick over fine ,boosting fine but no sound from the dump valve? when the car turned is off the top piston drops down,when you start the car on tick over it opens, when you rev the car it comes down again ,is this correct? but i carn't get the lower piston to open?is the how it should operate?its only running standard boost around 8 psi.