Airlocks rarely happen for no reason. They typically occur after the system has been tampered with or experienced a pressure drop.
The gurgle was the first sign that the universe was plotting against Arthur. airlock in plumbing system
Suddenly, the sink erupted.
: When you drain your pipes for repairs, air replaces the water. If the system isn't refilled and "bled" correctly, air pockets get trapped in high points. Airlocks rarely happen for no reason
Nothing. He hit them harder. Clang.
: In gravity-fed systems (common for hot water), the pressure from the header tank may be too weak to force air bubbles out of the pipes. airlock in plumbing system