The WP uses PIR to record the traffic in a washroom and control the hot and cold water. The WP is programmed to "shut off/close" a solenoid valve once no movement has been detected in a washroom for a preselected time period.
The valve is reopened automatically upon detection of movement. This in turn will save tremendous amounts of wasted water in the event of vandalism, cistern malfunction, taps being left open, etc.