You can rely on your sprinkler system watering the lawn and garden at the appointed time, and your water fountain always shuts off after you take a drink. If you have a fire alarm system with a sprinkler, any fire damage will be minimal. The water flow switch in these systems ensures that the water is dispensed at the right times. It sends an electrical signal to the switching unit in these and many other devices to indicate when to turn the water on and off. Wiring a water flow switch isn't difficult and you can do it yourself.
Turn off the fuse to cut the electricity going to the device to which you want to wire the water flow switch. Turn off the water. With a hacksaw, cut out a section of the PVC part of the water pipe that leads to your device. Refer to the instructions that come with the switch to cut out the right size section. Fit the switch into the space with the 'Water In' end towards the device you want to wire. Place it as level as you can for it to work properly. Connect the water pipes and seal the fittings with plumber's cement.
Unscrew the screws on the top cover of the switch. Take out the screws and remove the cover. Inside the switch, you'll see two wires with connection plugs on the end and two terminal plugs.
Plug the blue wire into the terminal plug marked "Normally Open," and plug the white wire into the plug marked "Normally closed."
The electrical conduit tubing on the flow switch has a red wire on one end. Twist that end of the conduit tubing into the threads of the conduit opening on the water flow switch. Do not twist the red wire.
Pull out the red wire, guide it over the flow switch and plug it into the "Power In" plug which is situated across from the "Normally Open" and "Normally closed" terminals.
Turn on the water and the electricity and plug the power cord of the water flow meter into an outlet.
Do not turn on the electricity until you are completely done.