By default verbose logging will not rotate logs so it will fill up disk space. Ideally you shouldn't be using verbose logging for extended periods in production.
That said, there are two files in the folder where the exe lives called log4net.debug and log4net.error. These are the log4net settings so you can control many parameters of how the program logs information. You can google up log4net and modify these files to specify settings that you want (including log rotation frequency, log size per file etc.).