Please refer to the manual to check if you have installed the correct type of sensor. You may need to replace the sensor with a new one. Please refer to the E+ electric unit heater installation manual (https://www.reznor.co.uk/wp-content/uploads/2024/08/Reznor-e-Installation-Manual-EN-2024-06-D301600-Iss-0-print-quality-1.pdf) for more information.
Why is my E+ display showing dashes (----) ?
Information on Reznor's range of warm air heaters