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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