Testing and Maintaining a DCVA
DCVA (double check valve assembly) - is a backflow preventer suitable for a moderate hazard. The DCVA is an excellent backflow preventer but unlike the RP; it does not visibly show when it has failed, so it cannot be used on a severe hazard and must be tested at least annually.
*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.
RP Testing Steps
- Check valve #1 - must remain closed in the direction of flow for 2 min, and have an inlet pressure 1 PSI higher than the outlet pressure.
- Check valve #2 - must remain closed in the direction of flow for 2 min, and have an inlet pressure 1 PSI higher than the outlet pressure.
- 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.
- Check valve #1 and #2 are not always interchangeable, even if they look the same.
- Always bleed the test cocks to remove dirt before attaching your gauges.
- Larger devices may have springs under pressure; caution should be taken when performing maintenance.
- Clean in-line strainers.
- If removing a backflow device from service place an electrical jumper across the pipe opening first.