## Parameters for garden irrigation

The following parameters for garden irrigation are important for your planing, water pressure and water flow:

• Which water pressure (bar) does the extraction source (faucet or garden pump) supply?
• Which water flow (l / min) is available?

These characteristics affect the number of sprinklers per pipeline string that can be connected behind a solenoid valve.

### Characteristic – water pressure

If there is no information available, there are two ways to determine the water pressure:

#### Find out the water pressure using a stopwatch

Although this method is not quite accurate, it gives an approximate value. For this purpose, a stopwatch and a water bucket is needed. First put a 10l bucket under the tap. Then turn on the faucet fully and simultaneously press the stopwatch. Once the bucket is full, the time spent is stopped. If it took about 25 seconds for the bucket to fill, the water pressure is about 5 bar. If the time is about 40 seconds, you can expect from about 3.5 bar.

#### Measure water pressure with the manometer

Of course, this solution provides the more accurate water pressure. For this one needs a manometer, which one can buy on-line. In addition, for Gardena water pipeline installation, a Gardena (# 2790-20) tee with 3/4″ female thread and a brass fitting reducer is required as the manometer has a 1/4″ thread water connection.

Information on installing the manometer can also be found on my YouTube channel.

The water pressure can be read directly on the pressure gauge. When planning the system, a permanently installed pressure gauge should be installed. In my water pipeline are about 3.8 bar pressure.

### Characteristic – water flow

To measure the water flow you need a 10l bucket. First, the water inlet is fully turned on and the time is measured by stopwatch, until the bucket is full. The measured time is then used in the following formula: (10 liters x 60) / time in seconds = flow rate in l / min

For example, the following values apply to the water flow:
15sec ==> 40l / min
30sec ==> 20l / min
40sec ==> 15l / min

Furthermore, you will find in my blog entry under checklist automatic garden irrigation, how to use the measured values for the planning of irrigation.

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## Calculation Hunter sprinkler

In the following blog I have written about Parameters for garden irrigation of the two parameters water pressure and water flow. These sizes are necessary for the planning of the irrigation system. Using the example of my irrigation installation, I show how to calculate Hunter sprinklers. This requires an overview of the Hunter systems, which can be found under the link. Finally, the individual products provide the respective operating data with information on water flow and water pressure. Hunter also offers a planning manual for garden irrigation.

### Calculate water flow

This results in the following values for the products of Hunter used in my garden:

For irrigating the lawn in the garden I use PGP Ultra / I-20 with a nozzle 2.5 blue. Due to the available water pressure of 3,5bar, the water flow rate is 9,7l / min. When using 2 sprinklers, I come to 2 x 9.7 l / min = 19.4 l / min.

In the front yard I use Hunter Pro-Spray PROS-06. By using different nozzles, I reach different casting distances and pitch circles as spray surfaces. This also results in different flow rates for the pro-sprayers used:

• 1 x nozzle 10-A, throw 3m, pitch 90 °, results in a water flow of 2l / min
• 2 x nozzle 6-A, throw 1.8m, pitch 90 °, results in a water flow of 0.95l / min
• 1 x nozzle 6-A, throw 1.8m, pitch 180 °, results in a water flow of 1.98 l / min

Consequently, for the front yard I come to a total water flow rate of 5.88 l / min.

Finally, from the two surfaces with the flow rates of 19.4 l / min and 5.88 l / min, a total of 25.28 l / min. Since I can provide 40l / min with my pump, there is still the possibility to expand the system.

### Calculation Hunter sprinkler – large garden

Through the use of valves in the individual irrigation circuits individual garden sections can be irrigated successively. Thus even under-performing garden pumps can irrigate larger gardens. For this it is necessary to automate the irrigation order. Accordingly I have connected my Hunter valves to the Homematic home automation. I have described the installation of Hunter solenoid valves in my blog installation Hunter valves PGV.

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