By Brad Haire
University of Georgia
Make sure the sprinkler heads are properly adjusted and not spraying too far out or too close in. Look for signs of broken risers beneath the sprinklers. Sometimes this is obvious: You'll have a traffic-stopping geyser. A cracked riser will allow water to boil up around the sprinkler.
Inspect the sprinkler riser wiper seal for flow-by. A small amount of water emitting past the wiper seal is acceptable while the system is running. Excessive flow-by while a system is operating indicates a damaged seal.
Many times people will replace a sprinkler because it leaks between the wiper seal and pop-up stem after the system has turned off. This leakage does not indicate a problem. If water drains out after the system has turned off and eventually stops, the valve is fine.
For spray heads with filters under the nozzle, hold the pop-up stem and unscrew the nozzle carefully. A damaged nozzle may result in an uneven spray pattern. A damaged pop-up stem will result in a poorly performing wiper seal. Remove and clean the filter.
To clean clogged nozzles, flush with water or lightly tap on a firm surface. While the filter is out, turn on the zone and flush out the sprinkler body. Reinstall the filter and nozzle, turn on the zone and recheck for effective coverage. Make all of the necessary adjustments to cover the area properly. While the water is on, inspect the other heads in the zone for proper operation.
To clean filters installed under the pop-up stem, unscrew the cap from the body. Don't allow dirt to fall into the sprinkler body while the riser assembly and cap are removed.
The filter is at the bottom of the riser assembly. Remove it and flush it with water. Before reinstalling the assembly, run a small amount of water through the system to flush any debris caught in the sprinkler body.
It's very important that broken or poorly performing sprinkler heads be replaced. When a specific sprinkler isn't operating as it's designed or if water is flowing freely because of a worn wiper seal, the performance of all the other heads in the zone is affected. Water flowing unchecked past a wiper seal will cause a loss in pressure and affect the other sprinklers' performances.
Valve problems can be hard to fix. Check with a professional if you think you have valve troubles.