Any irrigation system with a conventional irrigation controller can be upgraded to an unpowered system where each solenoid valve is replaced by an Unpowered Irrigation Controller with 25mm Valve. The conventional irrigation controller and the associated wiring become redundant.
 
This amazing invention lets you set the volume of water discharged by each dripper or sprinkler during the irrigation event. The dripper or sprinkler discharge is independent of the water supply pressure.
 
The Unpowered Irrigation Controller uses onsite evaporation and rainfall to control irrigation scheduling rather than the static timer intervals in conventional devices.
 
After irrigation and as water evaporates from the soil, water also evaporates from the container. The water in the container eventually reaches a low level corresponding to the soil drying out. The valve opens and irrigation begins. A control dripper attached to the irrigation system refills the container during the irrigation. When the water in the container reaches a high level corresponding to the required watering of the plants, the valve shuts off and the cycle restarts.
 
You can leave your irrigation application unattended for months on end.

The 25mm valve has flow control so that the flow can be adjusted to suit the pressure limitations of the irrigation application. For example, if you prefer not to use hose clamps on barbed fittings, you can use the flow control to reduce the pressure accordingly.
 
KEY FEATURES
Unpowered (no batteries, no wires, no solar panels, no electronics, no computers)
If you upgrade to the Unpowered Irrigation Controller, the conventional irrigation controller, the associated wiring and the solenoid valve become redundant
25 mm inlet and outlet
Operating pressure range 70 – 1034 kPa
Set the dripper discharge by adjusting the control dripper
The dripper or sprinkler discharge is independent of the water supply pressure
Adjust the interval between irrigation events by adjusting the float
Responds automatically to onsite evaporation and rainfall
The irrigation frequency increases significantly during a heat wave
When it rains, water enters the container and delays the start of the next irrigation
Simple, unpowered, and low tech, and therefore fewer things can go wrong
Leave your irrigation application unattended for months on end