Irrigation Business & Technology Online

Winter is not kind to irrigation equipment. Pump housings crack. Pipes bust. Gearboxes split. Growers can incur any number of costly repairs if they don't properly prepare irrigation components for freezing temperatures.

Winterization should begin in fall as soon as possible after the irrigation season concludes, said Mark Torkelson, part owner, Indiana Irrigation Co., an irrigation equipment distributor in Onward, Ind. "Some irrigation customers would be finished with their irrigation in late September and they could just go ahead and start preparing. Others still have watering to do and they'll have to be more careful."

Any time temperatures hover around or below freezing, Torkelson said, irrigation equipment is vulnerable to damage. "A lot of times a guy will look at the weather report and the expected low is 33 degrees Fahrenheit and he'll say, 'Well it can't freeze,'but what actually happens is when you factor in the dew point and other items you can get freezing temperatures in your immediate area. We've had people who have had their pumps freeze at temperatures above freezing," Torkelson said.

Water left in the system freezes and expands, thus putting undue stress on a variety of system components. Therefore, the principal aim of any winterization program should be draining or forcing water out of the systems.

The most common winter-related damage is to the outer casing, called the volute, of irrigation pumps. "That's the thing we see the most often neglected, and it usually results in repair costs anywhere from $200 to $600," Torkelson said. As water left in the pump freezes and expands it can crack the casing, which would then need replacement.

Furthermore, said Dave Veltema, owner, Spring Brook Irrigation, a distributor/ wholesaler in Holland, Mich., freezing water can bend the shaft of a centrifugal pump's motor. As a result, Veltema recommends that growers open the drain plug on the pump volute and drain out any water in early October. "It also breaks the vacuum on the suction side of the pump. That way there's no water on that whole suction side of the pump and into the whole pump case," he added.

Veltema cautions if you take off the suction line from a end-suction centrifugal pump, make sure to close the exposed opening to prevent access to rodents that will enter the area and potentially damage the pump.

Deep-well, submersible pumps come with there own set of unique required preparations. "Close gate valves and drain any fittings, so there is no water left in the system above ground. Also, get any water out of any parts of the line that are above ground," Veltema said.

Expansion caused by frozen water can also crack buried irrigation pipe, causing leaks that are difficult to pinpoint and repair .To prevent such maladies, growers should clear as much water as possible from lines using an air compressor. Veltema suggested growers use an air compressor capable of producing 185 or more cubic feet perminute of air pressure. Start the air moving from the connection fitting by the pump and discharge all water in the system lines to its outside extension. Keep the air moving through the system until you can't see water exiting the system. "That probably gets 70 percent of the water out. Some water will be left, but not enough to bust the pipe apart when it freezes," Veltema said.

Air should similarly be sent at high pressure through hard hose traveler systems to make sure water is blown out of piping. Water can also be drained from lines by putting the gun cart on a lower portion of the field and letting gravity drain the water out of the gun.

Center pivot systems are, for the most part, self draining, Veltema said, but growers need to make sure connecting pipes are drained before winter hits and end caps should be removed and cleaned.

Torkelson added condensation should be drained from the gearboxes on center pivots. "Sometimes you can have a large enough amount of condensation to freeze and break the gear box." To drain condensation, crack the gearbox drain a minute amount and the water will start draining off as it rests on the bottom of the gearbox. When oil starts to come out, that is a sure sign that you've drained off all the condensation, Torkelson added.

The above recommendations are just a few of the fall maintenance tips suggested for agricultural irrigation systems. For a complete list of winterizing tips consult the Winterization Checklist below While maintenance procedures can vary from system to system, even basic winter preparation can help prevent problems and save a grower time and expense in the spring and summer busy seasons.

WINTERIZATION CHECKLIST

Pump out or drain any buried pipelines.
Chlorinate wells.
Plug all holes in electrical control foxes to keep out rodents.
Check all motor openings to see if they are properly screened to protect against rodents.
Drain water from all pumps, pies, valves, tanks and similar equipment. Remove pump intake pipe from surface water sources.
Check gearboxes on center pivot towers and linear moves for water accumulation. Drain water and replace with oil. The grease or oil should be at the proper level to reduce moisture condensation.
Inflate tires of center pivots and linear move systems to proper pressure. Remove and clean the end cap on the center pivot.
Park the center pivot pointing in either a southeast or a northwest direction. to reduce potential wind damage.
Check the condition of the gaskets in portable aluminum of PVC pipes.
Flush chemical injector pumps and the associated equipment with water, then drain and store them in a clean, dry place. Chemigation pipes should be stored on racks to permit drainage. Gaskets should be removed and stored in clean water in a'place that will not freeze.
For oil-lubricated turbine pumps, open the oiler and let oil drip into the shaft bearings. Rotate the shaft to distribute the oil, allowing the oil to adhere to the bearings.
On belt-driven pumps, remove the belts and store them in a dry place. Reduce tension on belts that cannot be removed easily.
Check and service the flow meter and pressure gauge.
Internal combustion engines should be serviced and winterized for storage. Change the oil and filter, flush and refill the cooling system with the proper anti-freeze solution, seal all openings with weatherproof tape, loosen belts and remove the battery. Add a fuel stabilizer to gasoline engines or drain the entire fuel system. Do not drain diesel engines, but replace the fuel filter and leave all lines full of fuel. The vaporizer-regulator on natural gas or propane engines should be drained of both fuel and water. About 2 ounces of oil could be poured into the spark plug holes to coat and protect cylinder walls on spark ignition engines.
Check all openings on electric motors and control
boxes to make sure that they are properly screened to keep rodents-out. Control boxes should be latched shut to keep moisture and rodents out and switches locked in the off position.

Source: Tom Scherer, Agricultural Engineer, North Dakota State University in Water Spouts newsletter and Paul Jasa, Extension Engineer, University of Nebraska. in Crop Watch newsletter.