Resize System - walk through Duct Sizing

A valid route, preferably in single line with desired terminal flows set in it is loaded in the Duct Sizing utility. Checking of Duct Sizing Data is performed at least once using the Calculate command. Run Reports and review the pressure loss status. The All Routes report lists pressure loss in each path. The longest path of highest pressure loss is identified as critical path. The Section numbers listed in critical path are also highlighted in Duct Size table in different shade.

All Section report for Path Pressure loss

Arrange the view windows to make the geometry of currently loaded route visible in the working view. This is required during the walk through to access and analyze associated fittings in the duct sections. When a fitting or section of critical path is highlighted in Duct Sizing table, it is also getting selected in the geometry.

Achieving improve pressure loss by resizing duct fittings

Run the Reports > Sections > All option.
The Duct Sizing Reports All Routes report window opens listing all paths in the route and their pressure loss values in ascending order.
Analyse the Duct Sections in critical path. You may pick alternate duct size from the pull down list that smoothen the flow, Lock one of the values of Duct Size or Velocity or Pressure as allowed by the component in the design. You can always use the flyover hint to compare size in design to decide best match from alternates.
The altered values are to intent reducing pressure loss in the section and equalize the pressure across all section.

Note: If there is no downstream duct found for the section, a zero-length duct is created for the "Duct" category. This assists in the sizing method calculations.
Recalculate and observe critical path status. When ducts are set for desired values you can walk through Fittings.
Fittings category may have more than one duct component, and analysed further in the Fittings Loss Coefficient table.
Double click in the Summary of FLC column.
The Fitting Loss Coefficient Summary dialog opens listing all sections and type of fittings in it.
Observe the loss coefficient and reset the values and/or add override, as required. Apply/reassign correct ASHRAE fittings by selecting a valid one from the tree view list.
This is done to components that will have improved performance and grade in design, e.g. added insulation lining to a duct section, using damper to limit velocity etc.
For fittings assigned ASHRAE Fitting nos., will have standard loss coefficient values as published in the ASHRAE table. You will see a standard Loss Coefficient value assigned to each fitting. Looking at the values derived internally by the parameters (say, for a given r/D, for an elbow, or Qs/Qc for takeoff fittings) in case of Node-Branch, you may alter their Loss Coefficient overrides and set correction factor value to derive a minimal loss.
The default correction factor value for ducts and openings set to 1.0, however can be altered to expect desired pressure loss in the section.
Setting override suppresses the correction factor or loss value for the fitting.

Values set in FLC Summary table will also reflect in Duct Sizing table.
Switch to Duct Sizing summary and repeat the Calculate.
Repeat the steps of calibrating loss and coefficient values for next critical path until all sections are balanced for constant pressure loss.

Resized system rebuilds duct shapes to whole size increments when promoted to 3D model. This option attempts a physical resize of the HVAC system based on the computed values in the Duct Sizing table, keeping the sizes of terminal units and air handling source unaffected.

Note: Disconnected components due to physical constraint (beyond fitting limits) in the resize will be reported by initiating the View Disconnects.