Xylem IM255 AQUAVAR Intelligent Pump Controller - Manual (Page 82)

limited between 10 and 300 seconds. Ensure Flow Check Low Time is set long enough to
allow the pump to ramp down to the sleep frequency. Setting the Flow Check Low Time
longer or equal to the Ramp Down Time [3-42] will ensure the pump has time to ramp to
sleep during the Flow Check Low Time.
No Flow Power Calibration
A no flow condition can also be detected by monitoring the power consumption of the
pump. Typically a pump’s power consumption will drop when the pump is run at no flow.
The graph shown below illustrates a typical pump power curve at the pump design flow
and at no flow.
When the pump is operated at no flow, the power consumption will follow the no flow
power curve for that specific pump. The controller monitors the power consumption of
the pump. If the pump’s power consumption falls to the no flow power curve, a no flow
condition can be detected by the controller. In order to detect a no flow condition for
various pumps, the no flow power curve needs to be programmed in to the drive. The No
Flow Power Calibration Setup provides the method to program the no flow power curve
in to the controller.
Operation
80 Aquavar ® Intelligent Pump Controller INSTRUCTION MANUAL