If there is a loop in your ductwork, Design Master HVAC cannot calculate the CFM. If you cannot locate the loop based upon the information provided by the error, use the Coordinate Drawings and Database command on the drawing. It is possible that a duct that is in the database but not currently on the drawings is causing the problem.
If you have ductwork that actually has a loop in it, you need to model it in DM HVAC so that it does not have a loop:
- Choose a middle point in the loop and draw the ductwork from two sides toward that point. Have the endpoints of the two ducts meet at this location.
- Use the No Fitting command.
- Ribbon: DM HVAC->Ducts-> No Fitting
- Pulldown Menu: DM HVAC->Fittings->No Fitting
- Select the point where the two ducts meet. This will remove the end cap fitting from each of the ducts and they will appear to be a continuous section.
A correctly modeled loop is shown below.