Safety first: Turn off power or gas before adjusting sensors.

Check sensor placement: Ensure the Giant tank sensor or thermostat is properly insulated and not directly influenced by outlet piping.
Insulate piping: Insulate the first few feet of hot outlet pipe to reduce rapid temperature feedback.
Control settings: On advanced controls, adjust differential/hysteresis if allowed per Giant manual.
Monitor: If short cycling persists, consult a technician to evaluate sizing and control operation.

Water heater cycles on and off frequently with small temperature swings

Possible Causes