Things You'll Need
New sprinkler valve
PVC supply pipe
Sprinkler control wire
Adding a zone to an existing sprinkler system can allow you to cover more turf with the proper amount of water by reducing demand on other zones. Adding a new zone requires a sprinkler control box that's capable of expanding zones, as well as a new sprinkler valve that is added to the existing manifold control unit. This project takes about two hours to do properly.
Adding a Valve
Turn off the supply line to the sprinkler manifold. There is usually a control valve near the manifold control box.
Locate the sprinkler manifold. It's usually in an irrigation box buried underground with an exposed lid.
Remove the cap from the end of the existing manifold. This is where you will add a new control valve.
Apply a thin layer of PVC primer to the inside of the manifold tube where you just removed the cap. Follow that by applying a thin layer of PVC glue over the primer.
Insert a short length (about 5 inches) of PVC pipe that's the same diameter as the existing tube into the primed and glued opening.
On the other end of the short PVC pipe, apply a thin layer of primer and glue to the outside of the pipe, about one inch around the end.
Press one end of the control valve into the glued pipe. This will connect the valve to the existing system.
Apply PVC primer and glue to one end of a PVC supply line and quickly press the pipe into the other side of the valve. This line will take water from the valve to your new zone.
Continue connecting lengths of supply pipe until you reach the desired location for your new zone.
Connecting the Control Timer
Locate the control timer and remove the cover to expose the wiring diagram.
Identify an open zone port that is available to connect a new zone to. Each zone requires a positive and negative connection, so an open port should have two metal clamps or screws that do not have any wires attached.
Connect two sprinkler control wires to each connector in the open port by clamping them into place or tightening the set screws. Note which color wire is attached to the negative and positive sides of the port.
Run the wire to the sprinkler manifold box.
Attach the sprinkler control wires to the new valve's exposed wire. Place the positive wire from the control timer to the wire marked "positive" on the valve. Connect the wires with a wire cap.
Turn on the sprinkler water supply.
Test the new zone by selecting the port that you connected the wiring to from the control timer and running for five minutes.