Last week we covered how to select and place heads, as well as how to create zones and place manifolds. This week we’ll be moving further along in the design process and even get into some installation.
Picking up where we left off, we are now going to diagram our pipe layout. First, you will choose where to cut your mainline to add a tee fitting. This tee fitting will make it possible for you to maintain water flow to your home, while still having water flowing to your sprinkler lines. The line connecting your sprinkler line and main water line will need a shut-off valve. Including the tee fitting and shut-off valve, draw a line from your mainline to your sprinkler valve box. From the valve box, draw header lines out to each zone. Look for opportunities for piping to share trench space. Once you get your header lines out to the zones, draw lateral lines. From these lateral lines you will attach a riser that a sprinkler head will connect to. Please continue reading for more detailed explanations and diagrams.
What Type of Sprinkler Pipe Should I Use?
There are two types of piping used in residential sprinkler systems: PVC and Poly pipe. Though there are other types of pipe, these the are the two that you’re likely to encounter. We’ll discuss both briefly here, plus Orbit’s contribution, Eco-Lock Sprinkler Pipe.
PVC is generally considered the stronger material used in residential irrigation, but recent developments have made us re-evaluate that view. PVC is a hard, white plastic pipe. It has very little give to it, and is thicker than poly. PVC pipe does not bend too much (or at least shouldn’t), and if it does it will snap. While PVC can withstand higher pressures, both
PVC and poly ratings far exceed that which will ever occ
ur in a residential system.
There are some drawbacks to PVC. The way PVC is made includes the use of significant amounts of chemicals that are damaging to the environment and has led to talk from environmental and green building groups about abandoning PVC. Also, the fittings used to connect PVC pipe require the use of special PVC primer and cement.
Poly pipe is more flexible and not as thick as PVC, and its malleable properties give it added protection in freezing areas. Because it can be bent to match the contours of trenches, it is easier to work with, requiring fewer fittings, thus reducing necessary parts and installation time. It is also more affordable than PVC. Fittings used to connect poly pipe require the use of steel clamps.
The type of pipe you choose for your system will really be a personal preference as both have their pros and cons. PVC is a bit stronger and this should be a consideration if you’ll be doing minor digging, as it will be able to withstand a certain amount of impact more than Poly Pipe (though, neither of them will withstand very much impact). However, when it comes to repairs, the poly is certainly easier to work with.
You may have noticed that Orbit offers its own poly pipe, known as Eco-Lock Sprinkler Pipe. This green-colored poly pipe can be used with traditional fittings and our exclusive Eco-Lock fittings. PVC, as we mentioned before, is tougher to work with because it requires primer and cement in addition to its stiffness. Take it from a lot of professional experience, this is a hassle to work with. The primer and cement are messy and can’t be removed from clothes. Fittings need anywhere from 1-2 hours of dry time before you can run a system test. But Orbit’s locking fittings (both Eco-Lock and PVC-Lock) make installation faster and easier. They both operate by sealing fitting connections with rubber O-rings and stainless steel gripping teeth that are able to withstand over 1200 PSI. PVC-Lock and Eco-Lock fittings can swivel on the pipe to provide 360-degree directional adjustment.
How do I Diagram Pipe Layout?
Once your pipe has been chosen, you’re ready to diagram the layout. The water from the mainline enters your manifold contained in the valve box. Water is then released by individual valves to header lines. Header lines are usually no smaller than 1 inch and no sprinklers are attached. Rather, lateral lines branch off header lines within a single zone. Risers are attached to these lateral lines and sprinkler heads are attached to the risers. Lateral sprinkler lines are generally ¾ inch and risers are generally ½ inch pipe. The reason we don’t attach any sprinklers to the header line is because it will decrease pressure along the way, resulting in lower pressure at the end of the line. Thus, header lines are used to keep consistent water pressure. In the example below we have header line in black and lateral lines in red.
Remember, the shortest distance is a straight line, so try to make the lateral lines branch out perpendicular to the header lines.
If you’d like some graph paper to start drawing your diagram to scale, click here to download our sprinkler system preparation guide and use the graph paper for free.
Diagram the runs for future reference.
One of the unique advantages to Orbit’s Online Sprinkler System Design tool is that it maps out everything, even your pipe runs. This is useful when you put in the system, but also for future reference whenever digging is required to make repairs or add more heads. It’s nice to know where everything is years later. If you don’t use the tool, we still recommend doing this. Yards change and irrigation needs should change with it.
How do I Dig Trenches for My Sprinkler System?
Congrats! You’ve made it this far and now you’re ready to start the actual installation of your new irrigation system. First step: dig the trenches. You can dig these by hand or use a trenching machine. If you’re putting in an entire system, the trenching machine is really the way to go. If you are brave, you can rent the machine and do it yourself, otherwise, you can pay a contractor to dig the trenches for you. Although it does cost money, using the trenching machine is easier than digging by hand and you can usually dig all your trenches in a matter of hours.
[stextbox id=”warning” caption=”WARNING!”]WARNING! Whenever digging trenches in your yard it is imperative you take proper safety precautions, starting with having your local utility lines marked. If digging by hand, make sure to maintain correct posture, and take breaks as necessary. If you do it the wrong way you’ll hurt your back. Trust us on this one. If using a trencher, follow the instructions exactly. These are very powerful machines and even experienced operators have trouble with them sometimes. We also recommend wearing safety glasses and gloves.[/stextbox]
Okay, now that we’ve covered trenches, next, mark the lines. You’ve already drawn them on the diagram of your yard, so get some sprinkler flags and mark where each head will go. Next, get some spray paint used for ground marking and paint the lines on the ground. Once this is done, you’re ready to dig. If you already have grass in, you may consider putting a tarp down to throw loose dirt on as you dig your trenches. Cleanup will be much faster this way.
The trickiest part when trenching can be getting under the driveways, sidewalks, walkways, and other rocky or concrete features. The Orbit Walkway Tunnel Kit simplifies this process. This tool attaches to a hose end and uses water pressure to tunnel under these obstacles. To use the Orbit tunneling kit, dig a trench on both sides of the walkway or driveway. Attach a garden hose to the tunneling pipe. Next, turn on the faucet and work the pipe back and forth, allowing the water to spray and form a tunnel.
Now, besides digging a trench for each sprinkler line, you’ll need to dig for the main line (which municipal code may require to be a certain depth, depending on frost line conditions in your area), for the manifold boxes and a trench for the sprinkler wire leading from the manifold boxes to where your timer will be placed.
Speaking of timers…
What Control Timer Should I Select? Where Should I Install It?
Your timer is the brain of your underground sprinkler system. It controls when and how long you irrigate your yard. Orbit timers are known for their reliability, ease of installation, programming simplicity, and their 6 year warranty.
To help you narrow down your options, select a timer that will accommodate the number of zones your sprinkler system will need. Timers can usually control 4, 6, 9, or 12 zones. If you have more zones than this it will be necessary to purchase additional timers. Orbit offers a large selection of timers to fit your needs. They are all simple to use and easy to install. Pick the timer that suits your system’s needs and personal preference.
Where you put your timer is largely a matter of preference. Timers can be placed indoors or outdoors (with the use of weather resistant housings). Indoors tends to be more convenient (if an indoor space is close) and protects the timer from the elements. If your manifolds are some distance away from the manifold boxes we recommend some of our timers with remote controls that allow you to activate the different zones from a distance, which is extremely helpful when performing maintenance.
Remember to place your timer near a power source where you can access it easily. Also, consider running sprinkler wire through underground conduit to make any future expansions or repairs easier.
Next week join us again as we continue the installation. We’ll connect the system to the mainline, install necessary back-flow prevention devices, and lay the pipe.