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 valve #1 from which a sample can be drawn for testing or visual examination.

DCVA Maintenance Hints

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

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