WE RESERVE THE RIGHT TO MAKE TECHNICAL CHANGES. 1/3 ST M3200 ENG STA R2 03/17 M3200: PRESSURE SUSTAINING / RELIEF VALVE Pressure sustaining/relief control valves maintain a constant upstream pressure (valve inlet) by relieving ex- cess pressure. SUSTAINING APPLICATION - The valve is installed on a distribution line between two pressure zones. If de- mand on the lower zone causes a drop in upper zone pressure, the pressure is sustained at a preset mini- mum. When this occurs the pressure available to the downstream zone is reduced. RELIEF APPLICATION - The valve is installed to relieve excess pressure from a source. In a typical installa- tion the valve diverts excess flow/pressure to atmosphere, a storage tank, or back to a pump intake. ADDITIONAL FEATURES AVAILABLE: solenoid on-off control function - a remote controller switches the valve on-off; check function - if outlet pressure rises higher than inlet pressure, backflow is prevented; reverse flow - the main valve opens fully if outlet pressure is higher than inlet pressure; low pressure shut-off with manual reset; two adjustable pressure outlet values - switching can be by manual override, or remote electrical sole- noid control; flow rate control; on-off float device level control; constant level float control valve; booster pump control valve with check. OPERATING PRINCIPLE