How to Repair an Impact Sprinkler Head

An impact sprinkler is an effective irrigation system that can be used to water wide areas of lawns and gardens. The system works by spraying pressurized water on a given surface area uniformly. It mimics the effect of rainfall to ensure the grass on the lawn or the plants on the garden are well-watered.

The only problem is when the sprinkler starts to malfunction: all of a sudden, you might notice the area around the sprinkler head is downright marshy, while the rest of your lawn turns brown. Or maybe only half of your lawn is getting watered. This can certainly be infuriating, but there are also several easy steps you can take on your own to repair the impact sprinkler and optimize its performance. Keep reading to learn how.

Step 1 - Eliminate Simple Problems

Before you take any steps to repair the impact sprinkler, you need to know exactly what’s going wrong. There are a few tests you can do to determine the problem. Do some basic troubleshooting by checking for the obvious.

Make sure the timer is set correctly, the master shut off valve is open, the flow control is open, and the water pressure is at the correct level for your model. If any of these are not correct, adjust them and see if the problem fixes itself.

Step 2 - Try the Water Pressure Test

One of the most common issues with impact sprinklers is that they stop rotating. To rule out a simple question of water pressure, go to a working sprinkler head and push your hand on it to block the water flow; if the other heads start rotating, that simply means you need to increase water pressure in the system and open the flow control, which is easily done. However, if that doesn’t work, you’ll probably need to fix the irrigation valves in the rotors. Move on to step three to find out more.

Step 3 - Try Sandpaper

If your impact sprinkler head isn’t moving correctly and isn’t watering uniformly, one simple quick fix is to take some fine-grit sandpaper and gently rub all of its parts. This process can help reduce friction and encourage free and easy movement. Never ever spray your sprinkler with lubricants. This may provide a temporary solution, but in the long run, it will only cause more problems.

Step 4 - Clean the Sprinkler Parts of Any Debris

If the sprinkler is dirty or any parts are clogged with debris, this will keep it from watering your lawn as it’s supposed to. Remove the sprinkler and check for any buildup in or around the nozzle, swivel bearing, and inlet. Sometimes a small pin or needle can be inserted into the nozzle to loosen debris, but do not drill into the nozzle or alter it or you risk damaging it permanently.

Wash the rest of the sprinkler to get rid of grease and dirt and use a solution of vinegar and water to clean any water deposits.

You should also clean the solenoid valve. Unscrew the valve box with a screwdriver and take out the piece. Flush any debris therein and clean out mud with dry rags.

Step 5 - Check for Misaligned, Worn, or Damaged Parts

When you’re cleaning your sprinkler, study it closely to see if any of the components need to be replaced or adjusted. You may notice damage at first glance, so save yourself a little trouble and compare the problematic sprinkler to one that is still working. This way, any faulty parts should stick out to you a little better.

Two important pieces on the head are the trip pin and trip collar. The trip pin is the thin piece of metal at the base of the impact sprinkler, above the trip collars. This piece must be in a downward position for the proper oscillation to occur. However, if it is somehow out of place, it will not be able to move as it should. Generally this is easy to adjust back into place with a flathead screwdriver.

The trip collars set the boundaries for the watering range, so if they are out of their proper position, it will interfere with the sprinkler’s intended watering area. If they are too close together, for example, the sprinkler head will be restricted to facing one direction.

Adjust the trip collars by using your fingers to pinch the prongs and rotate them until they’re lined up with where you want your watering area to be. It stands as a given that if either of these two parts is damaged and unable to be adjusted that you’ll need to replace them.

Your bearing washers will also need replacing if any oil has been used to lubricate the head in the past. Oil attracts dirt and debris, which wears away the bearing washers even faster than normal use. If they’re less than 2/3 of their original thickness, they need to be switched out.

If the arm or body of the sprinkler has become bent or damaged, it’s easiest to detach and replace the part with an identical substitute.

Your arm spring might need an adjustment to its tension if it’s become too slack. For metal impact sprinklers, unhook the spring from the arm using needle-nose pliers; then, just bend it slightly before you re-hook it and test the tension. On a plastic model, you will re-hook the spring on the next protrusion on the arm instead.

Finally, it stands to reason that if you notice any other parts in the sprinkler that look damaged, you should try to replace them. These parts are not the only ones that can suffer a malfunction; they are just some of the most common.