Scan Types
There are 4 types of scan:
Single Show – A single show can be scanned manually.
Quick Scan - A ‘clever’ scan that looks in the download directory for shows to scan. It also scans missing episodes from the recent list.
Recent Scan – A scan that looks at all shows that have had an episode aired in the last few days. The number of days can be specified in the preferences.
Full Scan – Scans all shows that are set to be scanned.
Triggering Scans
These can be triggered in several ways:
On Startup
Via Command Line
Periodic (Automated)
When download/search folder/file changes
Manually
Configuration options are detailed in Options>Preferences>Scan Options
Further explanation can be found here.