The System Inspector is an on-model analysis tool. It shows flow, flow direction, static pressure, and pressure loss at each pipe segment of a connected system. The System Browser gives you a table of totals. The System Inspector shows how fluid actually moves through the network, segment by segment.
Workflow
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Before You Start
The system must be fully connected. Breaks in the pipe network, unjoined fittings, or fixtures and equipment outside the system will produce incomplete or misleading results. Use the System Browser first to clean these up.
Assign equipment to the system where possible, such as a pump, boiler, chiller, or water heater. This gives the inspector a defined source, so flow direction and the critical path calculate correctly.
Check that calculations are enabled. In the piping system type properties, the Calculations parameter should be set to All. If it's set to None or Flow Only, pressure data won't be available.
Know which systems suit this tool. The inspector is most useful for pressurized systems: hydronic supply and return, domestic hot and cold water, and fire protection. Gravity systems such as sanitary and vent depend on slope rather than pressure, so pressure results there are of limited value.
Open a view where the piping is clearly visible. A 3D view works best, but plans and sections also work.
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Launching the System Inspector
Select any element that belongs to the piping system: a pipe, fitting, valve, fixture, or piece of equipment.
If the selection doesn't work, use Tab to cycle until the whole system highlights, then click to select it.
On the Modify | Piping Systems contextual tab, click System Inspector.
In the inspector panel that appears, click Inspect.
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Reading the Results
Flow direction arrows appear along the pipe network. They show which way fluid moves through each segment.
Hover over any pipe segment or fitting to see a tooltip with:
flow (GPM) through that segment
static pressure
pressure loss for that segment, fitting, or valve
The critical path is highlighted in red. This is the route with the highest total pressure loss, the one that drives pump sizing.
Flow should accumulate as you move toward the source. Branches serving several fixtures or coils should carry their combined flow, and the main at the pump or equipment should carry the system total.
For plumbing fixtures, flows are derived from fixture units. Totals reflect diversity rather than a simple sum of fixture flows.
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What to Look For
Flow totals that don't add up. If a branch carries less flow than the fixtures or coils it serves, a component is probably not connected or is assigned to another system.
Arrows pointing the wrong way. This usually means a misconfigured system classification, an equipment connector set to the wrong flow direction, or no assigned source.
Segments with zero or no data. These are often disconnected stubs, dead legs, or pipes that are in the model but not part of the system.
Unexpectedly high pressure losses. These point to undersized pipes, excessive fittings, or high-loss valves, which are worth revisiting during pipe sizing.
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Making Adjustments
Exit the inspector to make changes. Then re-run it to confirm the results.
Common fixes:
reconnect broken pipe runs or fittings.
adjust flow values on coils or equipment connectors.
reassign fixtures or equipment between systems.
resize pipes or swap fittings and valves along the critical path.
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Exiting the System Inspector
Click Finish (or Cancel) on the inspector panel to return to normal editing.
Recommended Workflow
Confirm connectivity with the System Browser first.
Verify that equipment is assigned and calculations are set to All.
Select the system and open the System Inspector.
Click Inspect and trace the flow from the fixtures or coils back to the source equipment.
Check segment flows, flow direction, and the critical path.
Exit, correct any issues, and re-inspect until the results match your design intent.
Proceed to pipe sizing, or refine sizing based on pressure losses.