Water is warm but not hot enough, runs out quickly on electric Giant water heater

Safety first: Turn off power at the breaker and confirm with a meter.

• Check temperature setting: Verify both upper and lower thermostats on the Giant heater are set to the same desired temperature.
• Test lower element: Remove the lower access panel, disconnect wires from the element, and measure resistance. Replace the Giant lower element if open.
• Inspect thermostat wiring: Compare wiring to the Giant wiring diagram on the heater. Correct any miswired connections.
• Flush sediment: Drain and flush the tank to remove sediment that can insulate the lower element.
• Replace lower thermostat: If the element is good but never energizes, replace the lower thermostat.