May 8, 2009

10 Things to Check Each irrigation system will have a number of areas to lubricate or parts that may need to be replaced before the first irrigation. Here are 10 items to include on your irrigation system check-up. Change the engine oil and filter. Replace the air and fuel filters. Grease drive shafts on pump and motor. Check spark plugs on gas, propane, or natural gas motors. Drain, flush and refill the cooling system. Refill the drip oil reservoir and allow oil to drain into the drip line based on pump column length. Ensure that the right-angle gear head is free moving and clean and lubricate non-reverse pins. Run the motor at the normal operating speed for 45 minutes. Start the pump and walk along the system looking for malfunctioning sprinklers. Nozzle wear depends on the quality of the water and the system operating pressure. As a rule of thumb, sprinkler replacement should be considered after approximately 10,000 - 12,000 hours of operation. Be sure to replace malfunctioning nozzles with ones listed on the computer printout you received from the manufacturer. Check chemigation pump and safety equipment operation. Check hoses and replace if cracking is noticeable.

Performing a pre-season checkup of your irrigation equipment this spring should be part of your regular maintenance schedule.

Component wear happens, resulting in less uniform water application, increased energy use, and untimely breakdowns during your irrigation season. Identify and replace worn components now to have your system ready when you need it

Record System Data Monthly

One of the best ways to identify worn components such as sprinklers, pumps or irrigation systems is to keep good records. Recording the outlet pressure, flow rate, hours of operation, and energy use each month provides an excellent means of evaluating pump and motor performance and identifying changes.

The pivot should be in the same position each time the operating pressure is recorded since the pump will produce different outlet pressures depending on whether it's facing uphill or downhill. Also, systems that do not have pressure regulators to maintain sprinkler pressure will have different flow rates. Compare the current flow rate and pressure to last year's and the years before.

Test Safety Switches

Each irrigation system is equipped with a number of safety switches to shut the system down in the case of failure. Now is the best time to ensure that all these function properly. Run the system through a set of conditions that should cause each safety control to function.

Check System Efficiencies

Addressing the items above will ensure that the system will operate, however, a more difficult task is to determine how efficiently the system is functioning. Periodic pumping plant evaluations will help identify whether the pumping plant is operating at an optimum level.

The evalution should identify the overall operating efficiency and provide the pump outlet pressure, system flow rate, and energy use rate. This information will provide a base point to compare with future operating characteristics. If you have recent pumping plant evaluation results, simply compare the information you collect with the results to determine if the system is becoming less efficient over time.

In a Nutshell

 

• Regular record keeping can make it easier to track irrigation system energy use and identify when maintenance is needed on the pump or power supply.
• Visually inspecting the sprinkler in operation before the irrigation season starts can help identify whether water application is uniform and adequate and whether repairs are needed.
• Testing safety switches will ensure that, should a system component fail, the system will be shut down prior to causing major damage.

Bill Kranz, Extension Irrigation Specialist
Haskell Agricultural Laboratory, Concord