There are some helpful error codes that are displayed in the sea temperature field on the display, and accessible from the NMEA stream, alternatively, the power light indicator will flash to indicate an error.

To take advantage of the codes, you can set a page or panel up to view sea temperature. 

Light Blips
Code Meaning
5 55.5 WindBot stopped calculating True Wind 
6 66.6 Not receiving apparent Wind from Wind Sonic sensor
7 77.7 Not receiving IMU (Compass) data
9 99.9 Not receiving GPS data 

 Hierarchy: Codes with higher numbers trump those with lower numbers.