How to Repair a Leaking Sprinkler Manifold

What You'll Need
PVC glue
Dry rags or towels
New sprinkler manifold valve
Teflon plumber's tape
Penetrating oil (WD-40 is a good one)
Adjustable wrench

If you need to repair or replace a leaking sprinkler manifold in your lawn's irrigation system, you can use this simple step by step guide to learn how to make the job easier. This guide will show you to make common leak repairs on the manifold valve fitting in your sprinkler system.

Step 1 - Turn Off the Water

Turn off the water to the sprinkler system. If your system has a main isolation valve, turn the water off there. If the sprinkler system doesn't have this type of valve, then you'll need to shut off the water at the main shutoff valve, which should be located at or near the water meter for your home.

Step 2 - Dry Manifold Valve Surface

Take some old rags or towels and thoroughly dry the surface of the manifold valve fitting.

Step 3 - Apply PVC Glue to Crack

Locate the tiny hairline crack in the manifold valve that is causing the leak. Make sure the area is dry, and then apply a small amount of PVC glue to the cracked area. If the crack is a minor one, this should seal the crack and allow you to continue using the manifold valve fitting.

To Replace Faulty Sprinkler Manifold Valves:

Step 1 - Turn Off Water

Before you begin, make sure that the water to the sprinkler system is turned off. Again, do this by using the isolation valve for the sprinkler system or shutting off the water at the main shutoff valve at or near your water meter.

Step 2 - Remove Old Manifold Valve Fitting

Remove the butterfly valve fitting for your sprinkler manifold. If you are manifold valve uses compression nuts and threaded ends, you will simply need to loosen the nut and remove the valve. If the valve is difficult to remove, you may need to use some penetrating oil to loosen the nut. Apply the penetrating oil and wait for about 30 minutes before trying again.

Step 3 - Apply Teflon Tape to Male Threaded Joints

Once you have the old manifold valve fitting removed, you can install the new one. However, you must first use Teflon tape on the threaded ends of the joints where the valve will be connected. Is the valve you're using has dual male threaded ends, simply make four or five turns with the Teflon tape on those ends.

Step 4 - Attach New Sprinkler Manifold Valve

Insert the manifold valve fitting into the threaded pipe and turn clockwise until it is tight. Once you have the connector fitting hand-tght, use an adjustable wrench to turn the fitting an additional one half turn. Make sure not to over tighten the fitting or you may damage both the fitting and the pipe connector.

(Note - If your sprinkler system's manifold valve uses a butterfly valve that is glued into place (instead of screwed into threaded adapters), you will need to cut out the old manifold valve and replace it with a new one. However, when you do this, you may have to attach couplers to the PVC pipe to make up for the lost pipe length if you cannot push the ends of the pipe into the new butterfly valve.)