Pump controller displays E16 indicating internal temperature sensor fault; unit may derate or shut down.

Safety First: Disconnect power and wait for the drive to cool before opening the housing.

• Check ventilation: Ensure the Rheem drive enclosure is not blocked by debris or installed in direct sun without shade. Provide adequate airflow around the unit.
• Inspect thermistor connection: Inside the drive, locate the small sensor attached to the heatsink. Verify its wiring is intact and firmly connected to the control board.
• Look for overheating signs: Discoloration on the heatsink or PCB indicates chronic overheating. Address environmental causes (shade, airflow) and consider derating speed.
• Reset control: Power cycle and clear the error. If E16 returns immediately, the thermistor or board is likely defective.
• Replace drive module: On most Rheem drives, the temperature sensor is integral; replace the entire control/drive assembly if the sensor cannot be serviced separately.