Air Lock Plumbing [verified]

| Feature | Supply Air Lock | Drainage Vent Blockage | Mechanical Clog | | :--- | :--- | :--- | :--- | | | No water flow (sudden). | Slow drain, gurgling noise. | Slow drain, eventual backup. | | Cause | Trapped air pocket at high point. | Blocked roof vent stack. | Solid debris (grease, hair, roots). | | Physics | Compressible air balances hydraulic pressure. | Vacuum formation impedes flow. | Physical obstruction reduces diameter. | | Resolution | Hose bypass, bleed valves, AAVs. | Clear roof vent stack. | Chemicals or drain snaking. | | Prevention | Proper pipe sloping, auto-vents. | Roof vent maintenance. | Strainers, non-flushable items. |

In hydronic heating systems, air naturally rises to the highest radiators or towel rails. air lock plumbing

High points in horizontal pipe runs or lack of proper venting can trap air. | Feature | Supply Air Lock | Drainage

If a fixture has no flow but the main line is pressurized, perform these diagnostics: | | Cause | Trapped air pocket at high point

Air can enter a closed plumbing system in several ways: