This will help you winterize your pressure vacuum breaker and help you when your sprinklers don’t come on.
If your sprinklers are not working and your Backflow device looks like this, you have just found your first problem. The Discharge side of the backflow device has the horizontal pipe with the blue handle crossing the pipe. the discharge shutoff valve needs to be opened to restore flow the the sprinkler system.
If your sprinklers are not working and your Backflow device looks like this, you have just found your first problem. This is how you would winterize your sprinklers if you do not know where your isolation valve is located and you can't shut off your supply to the irrigation system. You will still need to open the test cocks on the right side of the backflow device with a flat head screwdriver to drain out the water. This is the best way to protect your backflow device (if you don't know where your shut off valve is)!
This is what your Pressure Vacuum Breaker will look like in Normal Operating Configuration. Full flow with sprinklers operating normally. If your sprinklers are not working on all of your zones, and your Backflow device does not look like this, you just found your first problem. Notice shut off valve on the supply side vertical pipe is in line with the pipe, this is the open position. Notice shut off valve on the discharge side horizontal pipe is in line with the pipe, this is the open position.
Notice the partially open/closed shut off valves. Notice the open test cocks. This can only be properly winterized if you know where the isolation valve is. The isolation valve will have to be closed before you can place the device into this configuration. The isolation valve is usually close to your water meter (with in a 3ft radius). If you can't locate it there, carefully check around the pressure vacuum breaker.