The first step for virtual retro-commissioning of any facility’s HVAC systems is to understand what those systems are and what they are intended to do. The starting point for this is document review, and the highest value documents include the following, if available.
Original Construction and Major Renovation Drawings — Many building owners have a set of the original construction drawings. Newer buildings will have electronic drawings, while older buildings may have paper drawings squirreled away in a closet, attic, or mechanical room. The latter can be scanned and shared electronically with the remote professional.