This is an unapproved modification to a backflow assembly for a commercial tanker fill station.
The equipment circled in this photograph should have been installed downstream of shutoff valve #2 where the arrow is pointing. Currently the device is installed between test cock #3 and test cock #4.
This backflow assembly failed the backflow test; however there is no way of knowing if this assembly is failing because of a bad check valve, or as a result of the unapproved improper installation. The backflow assembly must be disassembled and reassembled properly before an accurate backflow test can be made.
As a certified backflow assembly tester you must mark this as an improper installation and explain why in the remarks section on your test report. You are required to “inspect” as well as “test” the assembly. Your test report is a legal document, when filled out properly it will protect you from liability.
This defect is prohibiting the seat from coming into full contact with the seat gasket and the assembly to provide a watertight seal.
When inspecting parts during a repair, it is important to take the time to inspect the entire part not just one side for damage, manufacturing defects, etc.
Click photo to enlarge
Some time after that and prior to the home being sold the assembly began to vent water. Most likely the builder, in his infinite wisdom, had a carpenter fix it. The odds are the technician damaged the piston O-ring upon reassembly causing water to flow through the relief valve stem vent. The technician rectified the problem by plugging the relief valve stem vent with a screw. The technician also failed to reinstall the relief valve spring. As a result he succeeded in making sure the relief valve would never open again.
This is just one reason why we test the backflow assemblies annually. Aside from failures due to normal wear and tear, there are folks out there who think they are doing the right thing by modifying an assembly in an attempt to repair it. These modifications reduced a high hazard protection backflow assembly, to a low hazard device, and of course this is not allowed.
This is a new installation of an 8” Colt 300BF with a ¾” Ames 2000BM3 detector assembly.
If you look closely you will see the upstream side of the ¾” Ames 2000BM3 is connected to shut off valve #2, and the downstream side is connected to shut off valve #1. The detector meter itself is connected correctly with the direction of flow arrow pointing up. However with the way this is set up the detector meter can only run backwards.
This is an improper installation which has created an unprotected cross connection.
Click photo to enlarge
Here we have a very old 3” Beeco C6 Reduced Pressure Backflow Assembly on a domestic water line. Everything is still working like new, the test values are very very good and the shut off valves still close tight.
All this and this backflow assembly is on a cast iron plumbing system. It would not surprise me if this backflow preventer lasted another 10+ years.