Why does the app show an amber alert icon with a "Sensor reading error"?

For R3W (WiFi) sensors running v64 firmware or above, the sensor will self-report reading errors. This will show as an 'amber' alert icon in the app, with a fault message of "Sensor reading error". 

This occurs when the radar sensor has been unable to take a valid reading. It is most commonly caused by obstructions between the radar sensor and the water surface. 

To resolve sensor reading errors with R3W or R3L sensors, try the following steps:

• Check that there are no obstructions (pipework etc) inside the tank that could be in the line-of-sight of the radar.
• Check that the sensor is mounted at least 300mm away from any tank walls or dividers.
• Take the sensor off the tank and check for any moisture build-up on the lens underneath the sensor, or other obstructions such as dirt or spider webs. Dry all areas if you find any moisture.
• Then try taking a manual reading by pushing the READ button to see if the water level reading changes. 
• Taking a test reading away from the tank can also be useful to diagnose errors - using any hard surface for this.