Wilkins 975XL RPBA installed below ground on an irrigation system

This is an improper installation of a Wilkins 975XL RPBA installed below ground on an irrigation system. This is not allowed because if check valve #1 should fail the relief valve will vent filling the box and covering the backflow prevention assembly with water creating an unprotected indirect cross connection.

Upon completion of testing the backflow preventer you must check (Improper Installation) and note it in the remarks.

Click to enlarge

This is an approved ½” Air Gap set up supplying water to radioactive equipment. When there is a demand for water; the pump on the lower left will start; water in the storage vessel will drop; the float will open the water supply line. When the demand stops the system will return to the static state shown here.

Back in the early 1970s when the cross connection program was in its infancy, rules and regulation were still being ironed out. It was the wild wild west of the cross connection era.

This backflow device was installed in 1971. It does not meet modern standards or regulations: 1) It is not testable; 2) A PRV & a Wye strainer have been installed between shut off valve #1 and the check valve assemblies.

Click Photo to Enlarge

As a BAT in Washington State you are required to inspect every backflow prevention assembly you test. Part of your inspection process is to identify and report unprotected cross connections like this one pictured here at an elementary school.

You must report any plumbing attached to the test cocks period.

This is a 3” RP Backflow Assembly for the domestic water with 2 visible problems.

1) The relief valve is continuously venting water indicating a failure.

2) A hose bib has been attached to test cock #1 creating the potential for an unprotected cross connection. This is not allowed in Washington State. It is the duty of a BAT here to note it on the backflow assembly test report.          Click to Enlarge

Here in Miami Beach Florida most all backflow prevention assemblies are above ground and out in the open. Must be nice not to have to deal with spider infested flooded vaults.

The big downside for the backflow tester here is most of the tags have been painted over or weathered to the point of not being readable. My son and I looked at about 100 assemblies but were only able to read the SN # on 10% of the devices.

I can read about 98 out of 100 BPA tags here in Seattle

Here we have a weighted/swing check single check valve backflow prevention device. This device is not testable. I’ve taken the liberty of attempting to group all the internal parts together to give you a general idea of its design.

From lower left to right, check valve weight, the check valve, weight & check valve brackets, retainers, & pins, and 8 cover bolts.

Click on photo to enlarge.

This is a ¾” Watts 009M3QT number 2 check valve.

Over time the hot water running through this backflow assembly has caused the check valve retainer to breakdown and get lodged in check valve #2.

Here we have a check valve out of a 2” Watts backflow prevention assembly.

The seat of the assembly has cut a groove into disk causing pieces of the disk to break off and flow downstream. This is usually a sign of Excessive Backpressure.

This check valve leaked and did not pass the annual backflow test.

Click photo to enlarge.

In general you have to deal with flooded vaults from time to time. After you get them pumped out you climb into a slimy hole to do the backflow test.

But every once in a while you will run into one like this 1 in a shopping center parking lot in Redmond Washington. It is half full of oily sludge. You cannot pump this into the street. You have to pump this toxin into containers and properly dispose of it at a hazmat site.

You also must also follow OSHAs confined space guide lines or this backflow test may be the last one you do.