What causes nuisance dripping of backflow preventers and how is it correctable?

We get quite a few calls about and returns of perfectly good 573 Series backflow preventers because double-check atmospheric vent backflow preventers are not fully understood. Usually they have debris/dirt buildup in the seals, which is easily corrected by cleaning. If a picture is worth a thousand words, is a video worth a million? Bob “Hot Rod” Rohr gives you a look under the hood on how a double-check atmospheric vent backflow preventer works.