Pipes, Boxes, Valves, and HeadsJune 3, 2013
Now that you are officially an expert in connecting to the water source with backflow protection and pipe placement, we’ll cover the rest of the installation process. We’ll go over how to connect the mainline, install your manifolds, connect each zone, install risers and heads, and connect sprinkler wire. Sounds like a lot, but it really will be easy once you get started.
How to Install the Valve Manifold
The first step to installing your valve manifold is to install a valve box. Select a location that complies with the following guidelines. Avoid installing the manifold and valve box near:
downward slopes to the house
First, dig a 26″ x 20″ hole to the recommended depth. Next, add a 2″ layer of crushed rock to serve as a drainage base for the valve manifold. (See the graphic above for an example.) Once the gravel is spread evenly, place the Orbit Valve Box Base on the gravel bed. Next, place the Orbit Pre-Assembled Manifold on top the the base. You will then want to remove the side knockouts for each valve in the box and also for the incoming mainline.
Orbit valve boxes come in a variety of shapes and sizes. The circular valve boxes come in a 7″ or 10″ option. There are also the 12″ Standard and 20″ Jumbo Valve Boxes. The Standard Valve Box can hold up to four valves and the Jumbo Valve Box can hold up to six valves.
How to Install Main Line
Now that your valve box and manifold are ready to go, it is time in connect your main water line to the manifold. From the shut off valve that you installed previously, run your mainline to where you have installed your valve box and manifold. It is recommended that your mainline pipe be one size larger than your supply line to maintain water flow throughout the system. Smaller pipe will reduce your water flow and will lead to gaps in spray coverage. An example would be to use 1″ pipe if your supply line is ¾″. It is recommended that you use Schedule 40 PVC Pipe to bring water into your valves. Schedule 40 PVC can withstand working pressures of up to 450 PSI. In looking at the diagram to the left, you will notice a 1″ PVC Slip Coupling attached to the Orbit 2-Valve Pre-Assembled Manifold. This must be attached using PVC primer and cement. It is important that the mainline pipe be as deep as possible in the trenches in order to provide room for the pipes coming from each valve to the sprinkler zones.
How to Connect Zones
Now you’ll want to connect the zones you installed last week. Make note of which zone is coming into which manifold so that when you test the system it will be easy to keep track of what is what.
Before installing any sprinkler heads, you’ll want to flush the system of any debris by running water for a couple minutes on each zone. Debris inside the pipes is inevitable, but left unattended it will cause buildup and problems with either the heads or the valves (or both).
How to Install Risers and Sprinkler Heads
Risers are the connections that will bring your sprinkler heads up to ground level. There are a number of risers you could use. These range from simple risers, poly swing joints, traditional swing joints, and flex pipe. Depending on your head type and needs, select the type you prefer for your system.
Installing heads to your risers is usually just as simple as screwing them on. Most pipes will not require the use of teflon tape, but some might, so be sure to check on that to prevent any leaks.
Now that you’ve installed your heads it’s a good idea to check for any leaks. Fill in the trenches with enough soil to stabilize the heads, but don’t fill in the hole all of the way in case you need to adjust or change anything. Turn on one valve at a time and check for any leaks in the risers or sprinkler heads.
Connecting Sprinkler Wire & Rain/Freeze Sensor
The hardest part is done! Your sprinklers are installed! If you can’t remember back to the first part of this blog series, we went over the benefits of installing an underground system. Some of those benefits were saving money through water conservation and adding curb appeal to your home. However, the biggest benefit of all for some homeowners is the time savings. Automated sprinkler systems save you time because, well, they’re automated! Now we’ll go over how we are going to automate the system.
Each sprinkler valve needs to be connected to the timer in order to electronically control the system. Sprinkler wire consists of one white (common) and 4 or 6 colored strands. The sprinkler wire needs to have at least one more wire strand than the number of valves being installed.
If you remember in our third blog we talked about timer placement and suggested running a line of conduit from your timer to your valve boxes.
Spend extra time to make sure your wires are completely sealed from any moisture, because if any water gets into the wiring, the solenoids are toast. Orbit offers grease caps made specifically for this job.
Install Auto-Drain Valves
Auto-drain valves are installed to help excess water drain out of the system. This is important especially in areas where freezing temperatures are a concern. They are simple to install. Simply attach a T-junction at the low point of your system. Don’t worry, water won’t drain when there is pressure in the system.
Testing the System
Now that everything is hooked up it’s time to test the system. Notice that we haven’t filled the trenches in yet. This is the last step. We want them to be unburied during the testing process so it’s easy to fix any problems. We’re not going to cover specifics of testing the system here because each timer is different. Refer to the timer’s instructions for details on how to do this. But we will say that you should run each zone for about 5-10 minutes, giving it enough time to clear any residual debris from the pipes. Look at each head and nozzle, make sure the flow is consistent and stretching as far as you expected. Look at the spray pattern and verify there is head-to-head coverage and check for leaks at all connection points. Any drips may seem minor, but these will only get worse as time goes on, so fix them now.
If everything looks good, you’re ready to fill in the trenches. Make sure you get under the pipes as well as over them. This will prevent issues when the dirt settles, which can lead to unattractive ruts in your lawn. Don’t stomp on the dirt, this could bend and break pipes. Instead, fill under and around the pipes, and then over them. Give it a couple days, to a week to naturally settle around the pipe. This might mean holding off on planting grass seed (if you planned on doing so), but it’ll be worth it because the ground will almost certainly need a little management after the fact.
This ends our series on underground irrigation planning on installation. Our next series will focus on some of our hose end solutions. Check back regularly for more tips and instructions. As always, we welcome your comments and questions.