As demonstrated with manual winterization requirements last month (Winterization and Commissioning, January 2019), systems manuals should include more than a regurgitation of the BAS as-built documents. Not everything in a project is necessarily controlled by the BAS, and, believe it or not, some buildings are still constructed with no central BAS at all.
Whereas very simple electric controls, such as thermostats for furnaces, fan-coil units, or heat pumps, can be self-explanatory, there are often more complex — but still stand-alone — controllers installed in non-BAS facilities. These can be little black boxes set up by the installation contractor, which, theoretically, require no user interface from the building operator and/or occupants. Any adjustment or troubleshooting will need to be performed by a service contractor with customized (proprietary?) tools.