One of the reasons we test a backflow assembly is to ensure its functionality per manufactures design and industry approved standards.
For example, a double check backflow preventer (DC) has two independent spring-loaded inline checks that are design to hold minimum of 1 psi pressure in the direction of flow.
We, at Simply Backflow Testing will test each check with a pressure gauge and if we obtain a minimum of 1 psi per check, the assembly will pass the annul backflow inspection. If we obtain a minimum of less than 1 psi on ether check, the assembly will fail the backflow testing. Repairs will need to take place before retest.
We are Los Angeles County certified backflow assembly testing company and pride ourselves for timely respond and scheduling in our neighborhoods in city of Van Nus, North Hollywood, Studio City, Glendale, Burbank, Pasadena and Los Angeles.