How to Replace a Sprinkler Diaphragm Valve

What You'll Need
Sprinkler system
Hand trowel
Phillips head screwdriver
New diaphragm valve
Waterproof wire connectors

If your sprinkler system is starting to get leaky, flooding the area around the sprinkler itself while the rest of the lawn turns brown, then it’s probably time to replace the diaphragm valve. Although it may sound intimidating, this is actually an easy enough job that do-it-yourselfers can undertake themselves without too much trouble and minimal expense. To learn how to replace the diaphragm valve in your sprinkler by yourself, just read the easy steps outlined below.

Step 1 – Shut Off the Water

Before you get started, turn off the water so that your mission to replace your sprinkler’s valve doesn’t turn into a long, messy shower.

Step 2 – Clean Out the Valve Box

Once you’re sure that you’re safe from unexpected bursts of water, pop the lid off of the sprinkler’s valve box. It will probably be a wet and muddy mess on the inside, which will definitely make your job a lot harder. Use a hand trowel to scoop out the mud, then stuff some dry rags in the box to help soak up excess moisture and wipe away any leftover mud.

Step 3 – Remove the Solenoid Valve

Take out the solenoid valve by twisting it out of place. It will still be filled with water, so wait for it to drain before proceeding.

Step 4 – Install the New Valve Diaphragm

Once the excess water has drained, take your Phillips head screwdriver and undo the screws that hold the bonnet to the top of the solenoid valve, as well as the steel ring that surrounds the bonnet. Make sure to keep the screws and the ring handy for later; don’t lose them in the mud! Inside the valve, you will find a diaphragm gasket and a spring. Take them both out. Then, insert the new diaphragm valve into the solenoid valve, making sure it’s securely in place.

Step 5 – Reassemble the Solenoid Valve

Take the old spring and gently place it on top of the new diaphragm valve, and place the old bonnet on top of that. Replace the steel ring, and find those screws from Step 4. Use your Phillips head screw driver to reinsert the screws, making sure they’re good and tight.

Step 6 – Reassemble the Sprinkler

Now that the diaphragm has been replaced, you can reinsert the entire valve into the sprinkler. Use waterproof wire connectors to reconnect the valve and sprinkler to the correct wire connections. Finally, don’t forget to remove all of those rags from the valve box, lest they should impede the proper functioning of the sprinkler. Replace them with some clean stones or pebbles instead, which will also help keep the new valve free from the mud and gunk that may have clogged up the old diaphragm in the first place. As a last step, turn the sprinkler on to make sure that it is working correctly and not leaking.