Previous and Next Ducts

The commands in Design Master HVAC sometimes reference next and previous ducts. This section describes how to identify those ducts in your system.

These terms are used when discussing ducts that are connected to a specific duct. The duct you are working with is labeled Reference duct in the image below.

The Previous duct is the duct that runs toward the equipment from the reference duct. It is typically larger than the reference duct. For supply ducts, previous ducts are upstream from the reference duct. For return ducts, previous ducts are downstream from the reference duct. Ducts only have a single previous duct.

Next ducts refer to the ducts that run toward the diffusers from the reference duct. They are typically smaller than the reference duct. For supply ducts, next ducts are downstream from the reference duct. For return ducts, next ducts are upstream from the reference duct. Ducts can have multiple next ducts.

If Return and Exhaust Arrow Direction is set to Flow direction, the previous duct always points to the reference duct. The next ducts point away from the reference duct.