Hayward Pool Heater Error Code 12: How to Fix It

Q: What does error code 12 mean on a Hayward pool heater?

Error code 12 indicates a water temperature sensor fault. The heater's control board is not receiving a valid signal from the thermistor that measures pool water temperature.

Q: How do I reset a Hayward pool heater error code 12?

Turn off the heater and disconnect power at the breaker for 5 minutes. Reconnect power and restart the heater. If the error returns, further troubleshooting is needed.

Q: Can I replace the temperature sensor myself?

Yes, with basic DIY skills and a multimeter. You need to order the correct sensor for your model, drain the water line if necessary, and replace it. Ensure power is off.

Q: How much does it cost to fix error code 12?

If you DIY, a replacement sensor costs $20-$50. Hiring a pro may cost $150-$300 including service call and labor.

Q: Is error code 12 dangerous?

No, it is not dangerous. The heater will not operate until the sensor issue is resolved, preventing potential overheating or malfunction.

Abstract

Error code 12 on your Hayward pool heater indicates a water temperature sensor fault. This means the heater's control system is not receiving a proper signal from the thermistor that measures water temperature. This guide will walk you through common fixes, from simple resets to sensor replacement.