Abstract: An autoclosing flow-control valve assembly has a housing forming an inlet chamber normally filled with a fluid under pressure, an outlet chamber, and a main valve seat between the chambers. A piston defining in the housing a control chamber carries a valve element sealingly engageable with the seat. A piston spring braced between the piston and the housing urges the piston and element into the closed position. The piston is formed with a small bleed passage extending between the control chamber and the outlet chamber. A control passage extending between the inlet chamber and the control chamber has a pilot valve that when open pressurizes the control chamber and pushes the piston and element into the open position and when closed blocks flow through the control passage. An actuating member is actuatable to open the pilot valve and an actuating spring braced between the member and the housing urges the member out of contact with the pilot valve.