Hunter Technical Support Document
How do I learn flow for the highest station with a Hunter Flow Clik?
Calibrating the Flow-Clik to the Irrigation System
Using the Flow-Clik’s Interface Box, the sensor is calibrated by pressing the Calibrate button while the highest flow zone is operating. While the system is “learning” the flow, the System Status Indicator light will be yellow. After a 10 second period of “learning” it will begin to monitor system flow.
If you already know the highest flow zone within the system:
1. Turn the Startup Delay dial to the 0 second position.
2. Turn the Interrupt Period dial to the Sensor Bypass/Calibrate position.
3. Manually activate the zone with the highest flow.
4. While the zone is operating, press and hold the Calibrate button on the Interface Box. The System Status Indicator light will change to yellow during the calibration process.
5. Turn the irrigation system off and set the Startup Delay and Interrupt Period settings on the Interface Box (see Setting the Startup Delay and Interrupt Period).
If you do not know the highest flow zone within the system:
Flow Estimate Calibration Method
In some cases, you may not know the zone with the highest flow. A guideline that will help you easily determine which zone valve has the highest flow (GPM) is to count the number of sprinklers on each zone. If there are zones with both sprays and rotors operating in the irrigation system, you can multiply each spray head by 2.0 GPM (7.5 l/hr), each medium range rotor by 4.0 GPM (15 l/hr), and each large range rotor by 15.0 GPM (56.25 l/hr) for a general estimate of total flow for each zone.
For a more accurate determination of total flow for each zone, it is recommended that you measure the nozzle pressure at each sprinkler zone and then look up the nozzle flow at that specific pressure in the nozzle performance data section of the manufacturer product catalog. Once a determination is made of the highest flow zone, you can use the procedure above to calibrate the Flow-Clik to the system.
1. Determine the approximate water pressure at the base of the sprinklers in each zone while the system is operating. In the illustrative example it has been determined that the sprinkler pressure in zone 4 is 50 psi (3.45 bars/344.74 KPa).
2. Identify the model of sprinkler and its associated nozzle for each valve. Valve 4 has Hunter I-20 rotors that have various nozzles based on the distance of throw and the arc of coverage needed. For reference, the quantities of each type of sprinkler and nozzle configuration for zone 4 is identified in the attached irrigation legend.
3. Determine the flow rate for each sprinkler and nozzle configuration. Based upon information found in the Hunter Catalog the associated flows for each Hunter I-20 sprinkler and nozzle configuration is listed in the attached irrigation legend.
4. Determine the total flow of all sprinklers on the zone. The total flow of zone 4 in this example is 18.9 GPM (71.44 l/min) as identified in the irrigation legend.