Annual Test on a Reduced-Pressure Assembly With a Slow-Dripping Relief Valve
A certified tester arrives at a commercial laundry to perform the annual test of a 3-inch reduced-pressure principle backflow prevention assembly installed on the domestic water service. The building has been in service for nine years and the assembly has no documented maintenance history. During the initial check, the relief valve discharges a slow, steady drip with no flow through the assembly. Static line pressure upstream is 78 psi. The tester closes the downstream shutoff valve and begins the standard test sequence. During the differential pressure across the first check, the gauge holds steady at 6.2 psi, but the relief valve continues to drip. The tester must decide whether to pass, fail, or repair before testing continues, and must document the condition properly.
1. The first-check differential holds at 6.2 psi, which is within the acceptable range. Should the tester record a passing result and move on? Explain your reasoning and state what the drip indicates.
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No. A passing first-check reading does not override a visible drip from the relief valve. The relief valve is the assembly's downstream protection device, and a continuous drip with no demand indicates that the relief valve seat is not sealing. Common causes include debris on the seat, a worn seat disc, or a damaged seat. Even if the first check holds 6.2 psi, the assembly is not functioning as intended because the relief valve is passing water to drain. The tester should stop the test, document the drip with a photo and a written note, and treat the assembly as failed until the relief valve is serviced. After repair, the full test sequence must be repeated from the beginning, because the repair can affect the differential readings. The report should note the condition found, the corrective action, and the final test results separately.
2. After the relief valve is cleaned and reseated, the tester repeats the test. The first check now holds 5.0 psi and the relief valve opens at 2.1 psi differential. The second check holds 1.2 psi. Are these results acceptable, and what should the tester do next?
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The first-check differential of 5.0 psi is acceptable because it is at or above the minimum required differential for a reduced-pressure assembly's first check, which is typically 5.0 psi. The relief valve opening at 2.1 psi differential is also within the acceptable opening range, which is typically 2.0 psi or greater. The second check holding 1.2 psi meets the typical minimum of 1.0 psi. All three readings are within range, so the assembly passes. The tester should record each reading, note that the relief valve was cleaned and reseated, and document that the full sequence was repeated after repair. The report should include the static line pressure, the date, the tester's certification number, and a clear statement that the assembly passed. The tester should also advise the owner to schedule the next annual test and to keep the repair record with the assembly.