Troubleshooting an Irrigation Valve

Flip Law - Thursday, November 15, 2012

irrigation valve

Do-it-yourself repair on irrigation valves

Having a home irrigation system for your landscaping is a great thing. No more dragging heavy hoses through your yard and struggling to water those hard to reach spots.

There are times where you will run into problems with your irrigation system, so here is a guide to troubleshoot some common problems with irrigation valves.

Valve Does Not Open: Check the irrigation controller to ensure that it is sending a 24 volt output to the valve. If there is not a 24 volt signal going to the valve then you have a controller problem. If the controller is sending a 24 volt signal, then go to the valve in question and check the voltage across the two wires connected to the valve solenoid. Most irrigation valve will open with as little as a 21 volt signal. If you are not getting power at the valve, then you probably have a cut wire somewhere between the valve and controller. If you have at least a 21 volt signal at the valve and it does not open then the most likely problem is the valve solenoid. Solenoids are easily replaced.

Valve Does Not Close: The first thing to check is to make sure that the valve has not been opened manually. Next you will want to check for leaks around the solenoid or between the valve body and valve bonnet. If there are no leaks then turn off the water supply at the source and remove the solenoid and check for debris around the base. Also remove the valve cover (or bonnet) and inspect the diaphragm for damage from debris.

Water Continues to Seep Out of Sprinkler Head After System is Off: This may not be a valve problem. Take a look at the elevation changes in your yard. If the water is seeping out of the lowest sprinkler head on a zone, then it is most likely low head drainage. This problem can be fixed by installing a Seal-A-Matic (SAM) head at the lowest point on the zone. SAM heads have a built-in check valve that prevents low head drainage. If you have water seeping out of other sprinklers as well then there is probably debris under the valve diaphragm or the valve diaphragm is damaged.

Troubleshooting an irrigation valve problem can be a tedious task, but with a few basic tools and a little patience the problem can be detected and the repair easily made.

W.P. Law, Inc. carries top quality irrigation systems and supplies. For a more complete valve troubleshooting guide visit our Troubleshooting Page.

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