A double detector check valve is a double check assembly used in backflow prevention to protect potable water supplies from contamination.

This particular type of backflow preventer used two check valves assembled in a series, and this is done for two reasons: one, if one check valve fails, another is still in place; and two, the closure of one valve reduced the pressure differential across the other, allowing a better seal and avoiding leakage.

The most common usages of a double detector check valve are on lawn irrigation systems, fire sprinklers, and combi-boiler systems.  If the hazard is higher, a more reliable check valve system is used, such as a reduced pressure zone backflow preventer.

Most major cities across the country require some sort of backflow preventer system, since Federal law requires the protection and supply of clean water to citizens.  Backflow has been and is a very real concern, so let’s take a brief look at the cause of backflow or back-siphonage.

Water systems function on a water-pressure theory.  Water pressure is increased at the city’s end of the water supply, and that water pressure “pushes” water from the potable water supply to individual homes and business.  All is well as long as the water pressure is higher at the city’s end of the system.

But what happens if the water pressure suddenly decreases?  This can happen quite easily if several water mains are opened to fight a fire, and it can happen during flooding situations.  In those cases, where there is a dramatic decrease in water pressure, the water will actually reverse flow, or backflow, meaning that contaminated water from inside homes and businesses will flow back to the main supply.

Then we have a contaminated water supply and everyone loses in that scenario.

Enter the double detector check valve.  Just as the name suggests, when water flowing in the wrong direction is detected, the two check valves will close, thus preventing the flow of water, and they will not open again until water begins flowing in the correct direction.

Problem solved!

Homeowners are required to have their water system inspected one each year.  For affordable backflow prevention, those in Texas turn to City Backflow Testing, licensed and certified pros in the backflow field.  When your family’s health is your chief concern, only the best will do, and the best is City Backflow Testing.  Why settle for less than the industry-leading experts in backflow testing?