Abstract: An apparatus and method for releasing pressure and draining a high pressure water system includes a valve comprising a valve body having an inner cavity for water to flow therethrough, an inlet opening and an outlet opening in fluid connection with the inner cavity, a valve seat assembly comprising a first biasing member exerting a force against a valve plunger cooperating with a seal to thereby substantially close the valve at or above a predetermined system pressure, and an override comprising a manual activator having a second biasing member and a cooperating member positioned to transmit to said valve seat assembly a force applied by an operator, to thereby manually open the valve when pressure exceeds the predetermined system pressure.