Davey Speedman Dual Pump Variable Speed Pump Control System - Manual (Page 54)

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As with all pressure systems a pressure tank is recommended for use in systems
with VSD pumps. The pressure tank is used to:
• Reduce the effects of Water Hammer
• Provide supplemental pressure in the system to reduce the cycle time of the
pump starts.
The size of the pressure tank is based on the number of starts required at very low flows. As the VSD Pump
will take up the lower flows the only requirement for the pressure tank is to supplement the pressure when the
VSD is at rest awaiting the system restart.
Be sure to have a full diameter pipe between the reticulation and the pressure tank. Do not install any
restrictors in this line.
PRE-CHARGE PRESSURE
Set the air pressure in the pressure tank at 10% below the System Cut-In Pressure. This must be done when
there is no pressure in the reticulation.
The Speedman can be used with most brands of VSD as all of the intelligence for operating the system is
held within the controller itself. Nonetheless the VSD needs to be set so that it will receive the correct control
signals from the Speedman. There are some important settings
VSD Rates
• VSD Inputs/Outputs
• Acceleration
• Deceleration
• Maximum Speed
VSD Inputs
• Digital input
• Digital Output
VSD Inputs/Outputs
1. Analogue Input - Set to VSD Speed reference - 0-10V DC
2. Digital input - Set to Start/Stop/Reset - Close contact for run - Open Stop/Reset
3. Digital Output - Set to VSD fault - Close contact for fault
There are configuration sheets for most brands of VSD’s. Contact your local agent for detailed information
about your specific VSD.
PRESSURE TANK REQUIREMENTS
VSD Settings