How can you identify and clear air locks in a cold water system?

• A. Listen for gurgling sounds, run all outlets to purge air, start at highest points and work down; ensure system is fully filled
• B. Increase main supply pressure to push air out
• C. Vent hot water only
• D. Remove all fixtures permanently

Answer: (A)

Air locks happen when pockets of air get trapped in the cold-water pipes, usually at high points, stopping water from flowing freely. You’ll often hear gurgling or see weak flow when you open outlets. The best way to clear them is to purge the air by opening outlets, starting from the highest points in the cold-water run and working down, so water pushes the air out as the system re-fills. Do this gradually until you get a steady, uninterrupted water flow and the system is fully filled with water. This approach uses the water itself to push air out without forcing more air in or damaging the system. Venting only the hot line, cranking up main pressure, or removing fixtures doesn’t properly address the trapped air and can cause other problems.