GSW electric water heater with electronic control shows E101 and no hot water

Safety: Turn off power at the breaker and verify with a non-contact voltage tester before opening any covers.

• Reset high limit: Remove the upper access panel and insulation. Press the red reset button on the upper thermostat firmly until it clicks.
• Inspect wiring: Check all screw terminals on the upper thermostat and element for tightness and signs of overheating. Tighten as needed.
• Test upper element (advanced): With power off and wires removed from the element, measure resistance across the element terminals. An open reading indicates a failed element that must be replaced with a GSW-compatible wattage and length.
• Replace element: Shut off cold water supply, attach a hose to the drain valve, and drain below the upper element level. Remove and replace the element using an element wrench. Refill and purge air before restoring power.