Each HVAC system must have a valid central system selected to perform the simulation. Leaving a system as “undefined” is not a valid choice. In this case, the system has been designated as either Existing or Altered. In both cases, you must describe the existing system. In the case of altered, this will describe the system before alterations are made.
In the Building Tree, navigate to the System level of the tree and click on the Existing System which is undefined and select a valid system from the Central System library.
← Error 1038