Cla-Val Models 136-03 and 636-03 Solenoid Control Valves are on-off control valves which either opens fully or closes drip-tight upon receiving an electrical signal to the solenoid pilot control. The valve consists of a Hytrol main valve, a three way solenoid and a high capacity three-way pilot valve. The solenoid control operates the three-way valve which alternately applies pressure to or relieves pressure from the diaphragm chamber of the main valve. It is furnished either normally open (de-energize solenoid to open) or normally closed (energize solenoid to open).