Honeywell Zone Valve, 1/2″ Inverted Flare, 24 Vac, 3 Way Diverting, Port A Normally Closed, 30 Second Nominal Opening Time, 20 Psi Maximum Differential Pressure ( Closeoff ), 18″ Leads, 3.5 Cv, Spring Return, Normally Closed SPST Auxiliary Switch, Manual Opener