Water temperature overshoots the setpoint by several degrees before the heater shuts off.

Safety first: No internal access is usually required; work via the control panel.

• Check differential setting: If the SPRSUN controller allows, reduce the temperature differential or hysteresis so the heater stops closer to the setpoint.
• Verify sensor placement: Ensure the water temperature sensor is installed in a location with good mixing, not in a dead-end pipe.
• Improve circulation: Run the pool pump at an adequate speed to ensure uniform water temperature.
• Firmware/parameter check: If overshoot is severe, a technician may need to review control parameters or update firmware.