What Does the HI/LO Error message mean on my COMMBOX?

The HI/LO error message means that the ambient sensor readings (on snow sensor) are out of reliable measuring range.

Ambient Temperature < -9˚F

Ambient Temperature > 54˚F

The system will continue to operate using constant predefined values. In addition, the display will alternate between “LO” and -11˚F for low temperature readings, and between “HI” and 55˚F for high temperature readings.