To experienced irrigation contractors, installing electric valves is like driving – you can do it almost automatically, without thinking. This can make it difficult to explain to a novice; however, by following the installation steps properly when installing an irrigation system, one will avoid inevitable problems and service calls in the future.
Installing electric valves is so mechanical to experienced irrigation contractors that if asked to explain the installation steps in-depth, they indubitably will leave something out.
In preparation, purchase the number of valves per number of zones called for on the job. Other items needed are valve boxes, approved waterproof wire connectors, small rock, Teflon tape and PVC cement or clamps, which depends on the type of pipe used on the job.
Establish the general areas where the valves will be placed to determine how many valve boxes need to be purchased. Valves can be buried directly in the soil, but most professionals use valve boxes. If there are two or three zones near the main water supply, a manifold is built, and the valves are placed together in a master or jumbo valve box. The remaining valves are installed one valve per valve box.
Mark the location where the valves are to be buried. Position them in inconspicuous areas, such as shrub beds, if possible, with the first valve being near the main water connection. Place remaining valves according to the specific areas of the property each zone will irrigate. Don’t compromise accessibility, and always mark on a drawing where the valve boxes are buried, for future reference.
“You want to do the job right the first time,” says Jeff Carowitz, vice president of marketing for Hunter Industries. “Working on sprinkler heads or the controller is as easy as repairing or replacing an electric valve. The first step is to choose carefully when shopping for valves and make sure you have a good quality valve — the right product for the job.”
Bury the valve box to grade, placing two to four inches of rock in the bottom of the hole. Situate the valve box on top of the rock, without the rock extending into the box. The valve will be above the rock, which provides for ample drainage. When running the supply line pipe, run the multi-strand wire at the same time.
Flush the water lines to remove dirt and debris. “One of the most common problems when first turning on a system is dirty water,” says George Cook, vice president of marketing for HIT Products, Inc. “The valve won’t turn off because the ports are clogged. That’s the reason all valves are designed to be disassembled, to clear out critical ports,” Cook explains.
Cut into the water supply line and attach a tee. To the tee, connect a riser to come up through the rock in the bottom of the valve box. Tape the multi-strand wire that was run with the supply line pipe to the riser. On top of the riser, place an elbow and a two and one-half inch nipple. Screw the valve to the nipple, noting the direction of the water flow through the valve indicated by the arrows on the valve.
“Every contractor has, at one time in his life, installed at least one valve backwards,” said Carowitz, “The valve generally won’t open, and if enough pressure is applied, it may do damage to the internal parts.”
Don’t over tighten the valve and always use Teflon tape on the threaded connections and PVC sealant for PVC connections. If you take a shortcut here, you’ll be back later, digging this valve up and repairing a leak.
“Always use Teflon tape,” Paul Cordura, president of HIT Products, Inc., recommends. “Pipe dope used for this purpose will get into the valve and clog up the ports. If you’re using valves with slip connections instead of threaded connections and use PVC sealant, make these glue connections above ground, and position the valve at an angle so the excess glue will run away from the valve. If the glue runs into the valve, it’ll get on the diaphragm and the valve won’t open. Be sure that the glue is dry on one side before gluing the second side,” Cordua stresses.
Attach another two-and-one-half-inch nipple to the other side of the valve, connecting one more elbow as was done on the previous side, and a riser going back down, just barely under the rocks. Connect an elbow to the end of the riser that will be joined with the sprinkler lines.
“Just as a cook who cleans up as he goes along ends up with a clean kitchen, the contractor who cleans up as he goes along ends up with a clean installation,” says Cordura. “Think of the valve as you would the carburetor of an automobile. You wouldn’t pour gas that had been sitting in a dirty five-gallon bucket into your car’s gas tank; it would clog the carburetor or fuel injection system. So does dirty water clog valves and sprinklers.”
If more than one valve is going into a valve box, it’s much easier to build a manifold before it goes into the ground. Attach the nipples into both sides of all valves being installed. Using an adapter, fasten a piece of pipe between each valve, making sure it’s long enough to cut out the valve later, if necessary. Depending on the number of valves and the location of the supply line pipe, elbows are used to design the manifold so it will fit in the master valve box.
“Choose valves with captive components, so if you ever have to work on the valve, the parts won’t float away when disassembling,” says Cook. He agrees with Carowitz that quality valves will last for decades in the ground if installed correctly.
Electric valves require 24 volts to operate. Eighteen-gauge multi-colored, multi-strand jacketed wire is used to coordinate valve zones with controller stations. The number of strands of wire is dependent upon the number of zones being installed; it’s recommended that a larger count wire be put in to cover zones which might have to be added later.
“Every system I install is color-coded the same way,” says Danny Wilson, crew chief of Moneta Farm Service, Inc., Irrigation Department, Moneta, Virginia. “I start with the first valve in line and that’s zone one on the controller. It’s wired to the red strand. Zone two is green; three is black and so on. The white strand is always the ground wire. When I have to service a valve and it’s wired with the green, I know its zone two. It’s just a simple system that I use.”
Attach a different colored wire to one wire on the valve, and the white wire, which is the ground wire, to the solenoid wire. Secure the wire splices with an approved waterproof wire nut encased in grease, DBY or dry splice product. Don’t take a shortcut on this step either.
“Electrical tape, dipping the splice in PVC cement or any other quick fix to save fifty cents is not worth the trouble it’ll cause,” Carowitz says. “Moisture will get into the connection, causing corrosion. This will cause a short or worse, creating a nightmare to repair. If you take the time to fix it right, the connection should last for decades.”
Once all the valves are wired, run the multi-strand wire in conduit from the first valve to the controller. Wire the colored wire to the corresponding station on the controller, and the white or common wire to the ground or common terminal on the controller.
Contractors have a choice between electric valves with or without flow control, and usually choose the valves with flow control. This feature allows you to reduce and balance the flow or pressure to specific zones.
After the valves have been installed and connected to the controller, close the flow control and manual bleed screws on the valves. When the water is turned on, the valve will remain closed and the valves can be checked for leaks.
If there are no leaks, turn the manual bleed screw to open the valve manually. Then open the flow control valve to adjust the sprinkler heads to the desired coverage, making sure all the heads are functioning. If any heads are fogging at the nozzle, reduce the flow until the fogging stops. Close the manual bleed screws, then shut the water off and turn the system back on with the controller. Let the system run through a complete cycle.
If every zone turns on, you have correctly installed the electric valves.
Up until a few years ago, valve boxes were available in a variety of sizes, but only in black with green lids. Today, the manufacturers have become “fashion conscious” and are offering valve or access boxes in colors to match the landscape. Ametek, NDS, and Carson Industries are three companies now offering tan lids for sand applications, red brick for brick applications, brown for mulch applications, gray for concrete applications, purple for reclaimed water, as well as the standard green and black.
Ametek has a white box, in addition to the standard black box, for dark situations where the contractor would like it to reflect light. Joel Andrew, customer service head of the Access Box Line for Ametek, says, “Over time, valve boxes may sink a bit in the ground. Rather than dig the whole set-up out, we offer extensions for the top of the box to again make it flush with the ground. The lid will snap right on the top of the extension.” A jumbo box lid is available with insulation to protect against freeze.
If you have ever taken over a system, you know how difficult it can be to locate the valves. Ametek has a metal locator lid that can be picked up by metal detectors, in case valves accidentally get covered up over time. This eliminates the problem, even on your own jobs.
NDS includes a brass insert, so that bolts may be easily added for locking the lids down.
All three companies’ lids are identified with ICV (Irrigation Control Valve) designation. In addition to the drop-in lids, they also offer overlapping lids that prevent dirt, muck and grass from settling in the crack between the body and the cover.
“As inconspicuous as a valve is, it’s the heart of an irrigation system,” says Carowitz. “If the valve doesn’t work properly, the whole system doesn’t work. The consequences of a failed valve are the most severe an irrigation system can have. It can fail open and wash everything away, or fail closed and everything dries up and dies. Valves are also the most difficult component in the system to change or work on. However, properly installed valves will stay in the ground, out of sight, out of mind, for decades.”
With this in mind, take pride in your work when installing electric valves. Follow all the steps, and avoid taking shortcuts. Do the job right the first time.
November December 2001