Cracks in the Brass

• When water is trapped inside the backflow vacuum breaker and freezes, the water expands but has nowhere to go. This builds up pressure, which can crack the brass housing of the backflow device. When this happens, water sprays from the cracks. You must replace the entire device when cracks form.
  
  

Broken O-ring

• Every backflow device has an o-ring at the top of the device. This rubber gasket seals water inside but can become corroded or develop cracks. A broken o-ring will leak at the top of the device. To replace an old o-ring, unscrew the top cover, remove the old gasket and insert a new one.
  
  

Bonnet and Poppet

• Every backflow device has a bonnet and poppet inside. These plastic pieces use water pressure to keep water from flowing back into the main line. These pieces are prone to damage when frozen. You can replace both pieces individually by removing the top cap, pulling out the old pieces and simply dropping in the new ones.