Have you encountered this issue (and/or elevations)? By crash I mean Revit stops responding, the blue spinning wheel of death. One cause I've identified is HVAC Zones. I've been able to resolve each on so far by deleting the related zone(s) and creating the zone(s) again. I haven't figured out what is going wrong with the zones. I'm just calling it corruption for now but I have no idea if it is something I can prevent or see first yet.
Happy to hear if any readers have encountered this situation too.