A rotary union having a housing, a rotor, and a post such that a fluid can be conveyed through the rotary union. An operational parameter of communications over the communications line may be tested and a determination as to whether the operational parameter meets an operational criteria established by at least one of the test parameters may be made. The spray gun modules further include a recirculation port communicating between the central passageway and a recirculation conduit in an adjacent support assembly. The records in data tables are identified as belonging to one or more families.