How to Troubleshoot a Vacuum's Pressure Breaker

Turn the sprinkler timer to the "on" or "manual run" position to begin the sprinkler cycle. Go to the pressure vacuum breaker outside.

Inspect the vacuum breaker for any leaks coming from the top cap. If there is any water coming from the cap, there is a problem with the breaker.

Turn the sprinkler timer to the "off" position and turn both of the ball valves on the pressure vacuum breaker 90 degrees clockwise. This will shut off the flow of water while you work.

Unscrew the retaining screw on the top of the cap using a screwdriver, or turn the entire cap counterclockwise by hand. Whether you need a screwdriver to remove the cap will depend on the model of vacuum breaker.

Pull out the poppet and bonnet assemblies from inside the vacuum breaker. The poppet and bonnet are made out of plastic and are designed to break in the event of freezing. Inspect both pieces for cracks or breaks. If either piece is broken or cracked, it must be replaced.

Discard the broken poppet or bonnet assembly and replace with a new unit. Most hardware stores carry universal replacement parts for vacuum breakers that will work with most models.

Place the poppet in the bottom of the vacuum breaker followed by the bonnet. Replace the cap and tighten the screw, if applicable.

Turn the ball valves on the vacuum breaker 90 degrees counterclockwise and set the sprinkler timer to the "on" or "manual run" position to test the vacuum breaker. Water may leak briefly from the cap as the system is pressurized, but should stop within 30 seconds.