Irrigation Inventories for Smarter Maintenance

By Tom Glazener

Spring is irrigation season, and, along with installations, renovations, and repairs, it’s the time for system maintenance.

Repair services work to get broken systems back up and functioning. Maintenance is about regular, preventative attention, keeping the system operating effectively and efficiently. Repair and maintenance work hand in hand, and property owners and managers should see both as a wise investment.

Here are the steps to make sure your maintenance checks are saving your customers from critical problems, and help them save water. Additionally, your detailed approach can help identify rebate possibilities from the local water and power authorities.

Make a site inventory

For each site you serve, make a detailed inventory of the irrigation system. If you’re lucky enough to have an as-built reference drawing for the site, much of the work is done. The task will be to confirm the components and note discrepancies. If no drawing exists, a satellite map image entered into a drawing program can do the trick, then enter the component details into a spreadsheet. Google Earth, Go iLawn and your county tax assessor’s GIS services are also sources of mapping information.

This process is much easier with a tool such as SprinklerMaps.com’s iPad app. It allows you to walk the site and place components on the GPS map on the screen. The map and associated database is stored for a monthly fee. If you do a lot of work in harsh environments, Juniper Systems’ hardened mapping handhelds may be your answer. Regardless the device or method you use, it is the information that is important here.

Check the point of connection

Check the water supply’s point of connection. If it is a water meter, note the model, size, and whether it reads in gallons or cubic feet. Also note the backflow preventer type, size, and date of last inspection. Log the static pressure at the number one test cock.

If the supply is a well, determine if it is dedicated to irrigation or shared with a building or group of buildings. What is the pump size, and what is the current pump depth? Find any drilling and repair logs if possible. Make a note if there has been significant change in the water or pump level in the well.

Determine if there is a pressure regulator, fertilizer injector or booster pump on the system and mark them on your map. Determine the mainline size and type. If there is a master valve, record the make, model and size and if it is normally open or closed. Normally open valves work with a flow meter on its point of connection. Locate it before moving on.

Identify the zone valves

Accurate reference drawings, though rare, make this process easier. If not, then onsite research is needed. Use a volt-ohm meter to check if there is good resistance to all the solenoids (typically 20-60 ohms). A location device such as the Greenlee 521 or Armada Pro800D is very helpful here. Track the commons, then confirm each solenoid identity with a “ping” on the common and the control wire. Interpolate from there to locate the remaining valves.

Label the valves and wires as you identify them. If multiple wires are hard to sort, a tone probe is a useful tool here. If the valve boxes are prone to overgrowth, consider attaching a metal plate to the valve box lid so a metal detector can be used to help find the buried box. If the system runs on a two-wire path with decoders, map these and their identifying name or serial number on your master document. Refer to the manufacturer for location tips as these can be brand-specific.

When operating the zones for the first time, use a remote control or a helper standing at the controller. Read static and dynamic pressures at the backflow, as well as flows at the water meter. If the system has a flow meter, you may have that information at the controller. With your map or handheld, mark out the zone’s heads and area of coverage.

Study the heads and emitters

Identify if fixed spray or rotor brand, model, and nozzle. Do the rotor heads rotate properly, and are they standalone or mixed with sprays? Mark any low head drainage or dry spots you notice, as well as the root zone depth and soil type.

For drip systems, confirm the zones have filters and pressure regulators. Are there any obvious breaks when the zones are run? Are perennial zones, annual zones and container zones separated? Are the drip zones tied into any spray or rotor zones?

Examine the controller

Note the make and model of the controller and its features. Is the valve wiring conventional or two-wire? Is it central control or standalone?

Are the programs complete? Record all controller schedules in as much detail as possible: day/date, start time(s), zone run time, water days or intervals. Note the controller features, such as cycle and soak, delay between stations, program recovery, etc.

A complete list of programming features should be available from the manufacturer’s website. If it’s an older controller, information should still be available, though it may be time to consider an upgrade.

Is it a Smart controller? If so, determine if it’s connected to an offsite signal, onsite weather station or soil moisture sensor. If there are any sensors on the system (rain, wind, freeze, moisture, solar radiation, temperature, etc.) are they connected to the controller via sensor terminals or spliced into the common wire? If there are no sensors, is the controller’s sensor jumper in place on the sensor terminals in the controller?

Take pictures of the controller installation and the entire wiring layout. Finally, use your volt-ohm meter to record input and output voltages for the controller, transformer and zone valves, and resistance readings for each of the valves. (You may already have read ohms for the valves during the valve location phase.)

Battery-operated controllers are great for isolated zones where wire may not be available. Unfortunately, they also get used in lieu of cable repair. If you ran across one while doing your valve inventory, add its settings and schedules to the controller information section. If the controller uses a two-wire path or a combination of standard wire and two-wire, describe it and take pictures.

Analyze and prioritize

Back at your office, review the site maps and the information you gathered. Based on your site research, you can structure a short- and long-term service and maintenance plan for the property. Not only will the plan help you determine what is most pressing, but it will help you guide your customer.

First, what needs immediate attention? Critical issues are those that are wasting huge amounts of water, causing a danger on site, or causing a system or subsystem failure. These are things such as a broken mainline that shows up when the master valve opens, system shutdown because of controller failure, and the like.

Sometimes the problems are less obvious. For example, a well pump that once served the irrigation system just fine is no longer doing the trick. The well service may have lowered the pump to meet a receding water table. Flows and pressures may still be adequate for the house needs, but not for the irrigation. This is where your initial site survey serves its purpose — it’s a guide to what may have changed since your last visit, which in this case would be the well pump’s depth.

Next, what are the important, but non-urgent issues? This would include an overly high zone flow for the mainline size. It should be corrected as soon as resources are available, and could contribute to a later mainline break, but probably not this afternoon or tomorrow. The solution is going to be reconfiguring the zone, so a budget and proposal are in order.

Other important but non-urgent issues would include trimming around heads, proposing high-efficiency nozzles for existing spray zones, pressure regulating heads for zones with high pressure, cleaning drip filters, checking root zones for deep percolation (water far below the active root zone), adding an onsite evapotranspiration (ET) sensor, redoing the watering schedules to enhance water savings, and so on.

Regular maintenance keeps systems performing their best, and helps you maintain the customer relationships and references that help you grow your business. Your awareness of current local water and power rebate programs can also allow you to offer these important services while offsetting the costs. Remember to check with the local water and power providers for rebate opportunities to help your customers achieve more efficient and effective irrigation systems.

Tom Glazener, CLIA, CIC, CID, CGIA, CLWM, is an irrigation instructor for Ewing Irrigation and Landscape Supply. He can be reached at tglazener@ewing1.com