GSW Hydraulic Shock / Expansion Noise

GSW water heater causes water hammer or banging noises in pipes when heating or when taps close

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

Possible Causes

No water hammer arrestors, High water pressure, Rapid valve closure, Thermal expansion in piping

Safety: No immediate hazard from the heater itself, but repeated shock can damage plumbing.

Check water pressure: Measure static pressure; if high, install or service a pressure-reducing valve.
Install hammer arrestors: Have a plumber install water hammer arrestors near quick-closing valves (dishwasher, washing machine).
Expansion control: Ensure a properly sized expansion tank is installed on the cold supply to the heater.
Secure piping: Add pipe clamps or supports to loose hot and cold lines near the heater.

Medium 3/5

Thermal Expansion Tank

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