While simulating a complex system with many equations and variables, is there a way to see which variables are unsolved?

Hello,

I need help debugging my STv1 file (attached). I am using the SolarTherm library, which is from version 3.2.2, and I am using version 3.2.3. If you go to Tools -> Options -> Libraries, you can change to version 3.2.3, and you can load SolarTherm by going to File -> System Libraries -> SolarTherm. I have a few questions about my STv1 file. Any help with any of the questions would be greatly appreciated.
STv1.mo


1. What are "A$" units exactly?
2. Do units matter if the value is 0?
3. Why is it when I check the model I have 186 variables, but when I simulate it I have 206 variables?
4. Is there a way to circumvent my error with Medium being a partial class?
5. Why do my variables P_elec and CL.oeff.eff have no remaining equations to be solved in?
6. Will a pure function calling an impure function cause any issues?
7. Will using a conditional component in a non-connect context cause any issues?
8. What could be causing " Internal error function lexer failed"?
9. Why is my the unit check module failing?
ScottWeatherSource.mo

I am currently running Modelica 3.2.3, and I am using the SolarTherm library which is from version 3.2.2. When I tried to use SolarTherm.Models.Sources.Weather.WeatherSource (the file is attached), I got an error stating "[SolarTherm.Models.Sources.Weather.WeatherSource: 32:2-32:25]: date.t is not a valid connector." Does anyone know a way to potentially fix this? Any help would be appreciated. Thank you!
WeatherSource.mo