My system isn't melting snow and everything is functioning correctly. What gives?
Do an amp draw test on the cables to verify proper operation.
What is the ambient air temperature?
In temperatures less than 17°F (–8.33°C) it is simply too cold to make operation practical. The system may run all day and night and not melt any snow at 17 degrees or less. The system can't generate enough BTUs to overcome the heatloss generated by very low temperatures.
LOW TEMPERATURE LOCK-OUT on SCV-DUAL The low temperature lock-out function disables unit operation in temperatures less than 17°F (–8.33°C) in those climates or during those seasons where it is simply too cold to make operation practical. The factory default low temperature lock-out setting is Off, meaning that the unit will try to activate the heaters regardless of ambient temperature.