Flow-Sync - System Considerations

Working With Flow-Sync

Hunter flow-capable controllers are designed to measure and record actual flow, shut off irrigation when a high flow condition occurs, and identify which stations caused the condition.

The controller’s Learn Mode samples each station individually, and learns a typical flow for each station in the system. During actual irrigation, the flow can be observed at the controller. Actual flows are recorded and stored in the controller facepack. The ACC or I-Core controller will also compare actual flows to the estimated total of all active stations, to see if there is an unacceptable difference, indicating a leak or break.

Consult the controller documentation closely for setup and operation of flow monitoring. It is vital to set the correct pipe size, so that the controller interprets the flow data correctly. It is also important to set adequate overage amounts (minimum is 15% over normal) and delays (default is one minute) to prevent false alarms.


Mainline Pressure Fluctuation

Some water sources may have varying pressure depending upon the demand for water upstream of the point of connection. During times of heavy demand, system pressure through the mainline may drop.

This is why the flow limit percentage and delay periods (set in the controller) are important, as false alarms lead to a lack of confidence in the system.

Additionally, excess air in irrigation piping causes the Flow-Sync impeller to spin freely during station startup, which may cause temporarily high readings. This problem may be reduced by installing check valves in the system, and by setting the alarm delay values to prevent premature alarms.


Proper System Maintenance and Operation

It is important that your irrigation system be maintained and is functioning properly for optimum performance. Check your irrigation system for any broken components or leaks also, making sure that all sprinklers are operating within the pressure ranges recommended by the manufacturer.

Hunter controllers equipped with flow terminals will have approximately 20 VDC present on the flow sensor terminals, with no flow input.

When flow begins, the voltage will pulse. On a standard voltmeter, the voltage will appear to drop, or pulsate. On voltmeters equipped with a frequency counter, the pulse frequency can be measured in Hz.

Flow Range
Operating Range (Gpm)
  Minimum* Suggested Maximum**
1" 2 17
1½" 5 35
2" 10 55
3" 28 120
4" 34 195

* Minimum recommended flow for accurate flow readings

** Good design practice dictates the maximum flow not to exceed 5ft/sec. Suggested maximum flow is based upon Class 200 IPS plastic pipe

Maximum Distance Between Controller/Sensor Decoder and Sensor: 1000 ft/300 m
Wire: 18 AWG/1 mm, 36”/1 m leads (Ø = diameter)

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