6.3

Low Pressure (Low Head) Compensation

If your Leeaky Hose is a long way from the source (more than 20 metres), or if the water volume delivery to the beginning of the Leeaky Hose is below the required rate, a larger diameter feeder hose will compensate in most cases. We recommend thin-walled polypipe in either 16mm or 19mm diameter. Doubling the diameter of the feeder hose increases the cross-sectional area by four times, so a small increase in diameter gives a lot more volume and enables much longer supply lines. Reducing joiners and ‘T’s are readily available to connect the feeder hose to 13mm so it matches Leeaky Hose.

USEFUL CONVERSION FACTORS

1.0 metre of elevation = 10kPa = 1.45psi
7.5 metre of elevation = 75kPa = 10.5psi
1.0 litre = 1000 millilitres 1.0 metre = 3 feet and 3 inches

6.4

Water Timers on Low Pressure

If you are planning to use a timer with low pressure irrigation, check with the supplier that the solenoid valve used to shut off the water will operate on low pressure. Many solenoid valves are designed in such a way that the incoming pressure assists the valve to close. As strange as it may sound, a valve of this type may not shut off a low pressure supply, so in effect it will be useless. To get around the problem you can put a solenoid on the high pressure side of the pressure reducing valve or regulating tap, so there is effectively high pressure on each side of the valve. The reducer or In-line valve can be preset to the desired low flow rate for Leeaky Hose.

If using a tank, you will have to find a valve that operates on low pressure.