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Why do I see "N/A" for all fire flow results for all nodes in the Fire Flow Node Table?
You may not have the calculation option set to perform the automated fire flow calculations. Go to Home > Options or Analysis > Options to open the calculation options (in V8i, go to Analysis > Calculation Options). Double-click the active calculation option (designated by the red check mark) to open the calculation options in Properties. Find the property "Calculation Type" and set this to "Fire Flow".
If the Calculation Type is set to Fire Flow, ensure that you are not encountering any red user notifications, which indicate a critical problem that prevents the model from being calculated. This link has common troubleshooting steps for these types of notifications: Troubleshooting the Network Unbalanced or Cannot solve network hydraulic equations user notification.
Results of "N/A" entries can also be caused by omission of the node from the fire flow selection set. Starting with WaterGEMS and WaterCAD CONNECT Edition Update 3 (version 10.03.04.05), the Fire Flow Node Report will be filtered to only display results for nodes included in the selection set used for the Fire Flow Nodes pulldown menu in the Fire Flow alternative. If you have an older version, you can filter the Fire Flow Node Report to remove elements with no results.
In you are using WaterGEMS or WaterCAD CONNECT Edition Update 3 version 10.03.03.72 or later, you may also see a user notification that says: "Pressure constraints violated before fire flow added. Double click for details and use “Nodes to exclude” if needed." This notification occurs when the calculated pressures in a system are already below the pressure constraints before any fire flows are added to a node. This will often be nodes that are on the suction side of the pump, which are more likely to have low pressures during a typical steady state or EPS run if the elevations of the pump and the upstream reservoir or tank have similar elevations. If this occurs, open the Fire Flow alternative and find the field "Node to Exclude." This is located near the pressure constraints in the upper right of the Fire Flow Alternative.
Understanding Automated Fire Flow Results
WaterGEMS and WaterCAD Automated Fire Flow FAQ