Abstract: A valve assembly for controlling discharge of hydraulic fluid from a high pressure hydraulic fluid container to a hydraulic fluid reservoir and including a valve body having a valve bore, a fluid inlet port communicating with the valve bore on one side of a valve seat, and a fluid outlet port communicating with the valve bore on an opposite side of the valve seat. A valve spool is housed in the valve bore and includes a valve member selectively engageable with the valve seat to prevent hydraulic fluid flow through the valve bore. The valve member is selectively biased against the valve seat by a valve piston housed in a valve cylinder, the valve piston being operably connected to the valve member such that hydraulic fluid pressure in the valve cylinder biases the valve member toward the valve seat.