Bermad 748 Pump Circulation, Pressure Sustaining Control Valve

• Line pressure driven
  • Independent operation
  • No motor required
  • Long term drip tight sealing
• Off-line (circulation) installation
  • Replaces in-line “active check valve”
  • Reduces system energy consumption
  • Low capital investment
  • Short valve operating time
  • Applicable to existing systemsSolenoid controlled
  • Low cost wiring
  • Wide ranges of pressures and voltages
• Check feature (spring loaded type)
  • Replaces line sized check valve
  • Fail-safe mechanical closure
• In-line serviceable – Easy maintenance
• Double chamber
  • Non-slam opening and closing characteristics
  • Protected diaphragm
  • Full powered opening and closing

Major Additional Features

• Relief override – 748 – 3Q
• Electronic control – 748 – 18
• Pump circulation and flow control valve – 749 – U
• Deep well pump electric control valve – 745

The Model 748 Pump Circulation and Pressure Sustaining Control Valve, installed off-line, enhances standard pump systems with advanced “active check valve” logic. It is particularly suited to:

• Large diameter systems where line sized automatic control valves are not available or very expensive.
• Existing systems with mechanical check valves
• System designs where mechanical check valves are preferred

During the pump starting and stopping processes the Model 748 circulates zero to 100% of pump discharge to suction, while sustaining discharge pressure slightly below system static pressure. It prevents pipeline surges by enabling a standard mechanical check valve to respond gradually:

• When the pump starts, it gradually closes, increasing to check valve upstream pressure
• Prior to pump stop, it gradually opens, reducing that pressure

Complete process control is accomplished by a dedicated controller that coordinates all system components.

The controller consists of three timers (TD1, TD2 & TD3) used for timing the process and for the control.