Backflow Prevention Practice Exam

Before testing a backflow preventer, the test cocks are flushed primarily to _____?

1. Clean dirt and possible corrosion buildup

2. Create a water flow condition

3. Purge air from the assembly

4. Verify water pressure

The correct answer is: Clean dirt and possible corrosion buildup

Flushing the test cocks before testing a backflow preventer is crucial for ensuring the accuracy and reliability of the test results. The primary purpose of flushing them is to clean out any dirt, debris, or potential corrosion buildup that may have accumulated within the test cocks or the piping leading to them. This buildup can interfere with the proper operation of the backflow preventer during the testing process, leading to skewed results. By removing these contaminants, the technician can ensure that water can flow freely and that the test can be conducted under accurate conditions, thereby providing reliable measurements of the device's performance. While purging air from the assembly and creating appropriate water flow conditions are also important factors in preparing for testing, the initial step of flushing addresses potential obstructions that could compromise the entire test process. Verifying water pressure might be part of the overall testing procedure, but it is not the primary reason for flushing the test cocks specifically.