Heater displays E13; may be associated with very cold inlet water or sensor issues

Safety: Turn off power and allow the heater to cool. Do not operate with known flow or temperature sensor faults.

• Check flow rate: Ensure the pump is sized correctly and running at adequate speed for the Sta-Rite heater. Clean filter and baskets.
• Inspect sensors: Locate both inlet and outlet temperature sensors on the water manifold. Verify they are fully inserted and wired correctly.
• Test sensor resistance: With power off, measure resistance of both sensors and compare to Sta-Rite charts. Replace any sensor that is out of tolerance.
• Evaluate for scale: If temperature rise across the heater is excessive, the heat exchanger may be internally restricted. Consider chemical descaling or replacing the Sta-Rite heat exchanger.