image by Seemann: morguefile.com
Lawn sprinklers work by using electronic water valves to control the flow of water. The electronic valves operate in the normally closed position. This means the valve remains closed unless the irrigation clock tells it to open. They usually work without any trouble, however when something goes wrong you need a systematic approach to finding a solution. When your sprinkler system will not operate properly, there are several things to check before calling in the professionals.
Check the obvious first. Check to see if the irrigation control clock has lost power. The cause of power loss can be a tripped circuit breaker (Check the household power panel.), a blown fuse in the clock, or the clock could have been unplugged.
If you have power, check to verify the water is on. Check the house water valve and the main irrigation valve to verify you have water. These will be located in a valve box next to the house.
If the clock has power and the water supply is on, attempt to turn the electronic irrigation valves on manually using the clock. Cycle the system manually a couple of times to see if you can get the valves to respond. Every clock operates slightly different. Follow the instructions provided for your clock to complete this step.
Locate the electronic irrigation valves in your yard. They will be located within a valve box either by the house or in the shrub beds next to the lawn. Once found, locate two wires that attach to the valve body. These two wires will lead you to the valve solenoid. Grasp the valve solenoid, and turn it slightly to the left. This will allow the valve to open manually, and water should flow.
If the water flows when turning the solenoid, the problem is electrical between the clock and the electronic valve. Clean and check the connections between the wire from the clock and the two wires leading into the solenoid. After cleaning these wire connections, turn the valve on manually using the clock. If this works, you are finished.
If you are unable to turn the water on manually by turning the solenoid in this step, go back to step 1 and verify the main water valve is on.
If the valves still will not operate electronically, the problem is likely in the valve solenoid. Test the solenoid if you have a volt-ohm meter to see if it is operating correctly. According to Rain Bird, a solenoid is "good if its resistance is between 20 and 60 ohms." Follow the instructions for your meter to make sure you operate it correctly.
If the solenoid tests out fine or if you do not have access to a volt-ohm meter, the problem will require a landscape professional with the proper test equipment to finish the trouble shooting.
If the solenoid tests bad, simply replace it and your system should work fine. These are easy to replace as they simply unscrew from the top of the valve. Make sure the water is off prior to removing it. Purchase a new one from your local home improvement store if you have the valve make and model. You can also purchase these direct from the manufacturer.