Double Check Assemblies
Double check assemblies are the most commonly approved type of backflow device for inline or underground sprinkler systems, and a good choice if you want to install indoors or underground. DCVAs, when installed underground or indoors, aid in sprinkler system winterization, as they are not exposed to freezing temperatures and aren't likely to suffer from frost damage. Double check assemblies are also less expensive than reduced pressure zone assemblies. However, double check valves are not approved as a backflow preventer for water systems containing hazardous substances.
There is some debate as to whether irrigation systems contain "hazardous" substances (chemicals or toxins which pose a serious health risk), or water which is merely "objectionable" (looks, tastes, or smells bad, but doesn't pose a health risk). Double check assemblies are generally considered safe for sprinkler systems which do not have chemicals injected into the water. Our selection of manufacturers includes Febco, Conbraco, and Wilkins. Each double check valve works in the same way; however there is variation between manufacturers in size selection, price range, and product features and specs. We recently added a new line of Febco double check valve assemblies. These new double check valves come with union ball valves. This makes them a little more expensive than the original models, but highly worth it for easy installation and removal, as well as maximum freeze protection.