PVB Testing and Maintenance


PVB (Pressure vacuum breaker) is designed to prevent back-siphonage of contaminated water into a potable system. Often PVB's are used as fixture isolation with an RP at the service to the building. PVB's must be installed 12" higher then the downstream piping.

*This article is only meant as a summary of the testing procedure, you are responsible to test backflow preventers to the standard of your authority having jurisdiction.

PVB - anti siphon PVB parts view

PVB Testing Steps

  1. Air inlet valve test - The air inlet valve must open at or before the internal pressure is 1 psi above atmospheric pressure.
  2. Check valve test - The check valve must close tight in the direction of flow with a 1 PSI differential.
  3. Static line pressure - you must record the static water pressure at the time of the test from test cock #1.




DCVA Maintenance Hints

  • Always use manufacturer's replacement parts.
  • Rubber parts should be changed every 5 years.
  • Always bleed the test cocks to remove dirt before attaching your gauges.