Display shows E12; unit may not start or may shut down intermittently.

Safety first: Disconnect power before accessing the sensor or control board.

• Locate ambient sensor: Find the small probe or sensor mounted near the air inlet of the SPRSUN unit, usually clipped to the grille or frame.
• Check placement: Ensure the sensor is not touching hot surfaces or enclosed inside the cabinet; it should be in free outdoor air.
• Inspect wiring: Follow the cable back to the control board and check for cuts, abrasions, or rodent damage. Confirm the connector is fully seated.
• Replace sensor: If wiring is intact and E12 persists, replace the ambient temperature sensor with the correct SPRSUN part.
• Re-test: Restore power and verify that the displayed ambient temperature is realistic and stable.