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Warning Messages in InfoWater Pro

The following is a listing on non-fatal warning messages that might be encountered during a successful analysis run. When these warnings occur, the Run Status Indicator (stop-light) on the Run Manager dialog box indicates yellow.

Format:

Warning Message  Suggested Action

  • Pump cannot deliver head. The pump is trying to deliver pressure greater than the shut-off head. Use a pump with a larger shutoff head.

  • Pump cannot deliver flow.  The flow required is greater than the maximum flow capacity of this pump. Use a pump with a larger flow capacity.

  • Flow control valve cannot deliver flow.  A flow control valve provides a restriction to flow to maintain a set flow through the valve. If the flow through a wide open valve is less than the set flow, the valve can not deliver the set flow. Reduce the flow setting on the valve or provide additional head at the valve.

  • Following nodes are disconnected at timestep [timestep]: [list of nodes]  One or more pipes are closed at the given timestep, therefore shutting off all flow to a portion of the network. Ensure that this action is appropriate and if not, change the controls or status associated with the pipes and re-run the analysis.  It should be noted that not all pipes connecting a junction node can be closed simultaneously.  Each junction node must have at least one connecting pipe open.  For example, a pipe connecting a dead-end junction node cannot be closed.  InfoWater Pro will identify all junction nodes that are disconnected and this data must be corrected before an analysis can be made.

  • System unbalanced.  This condition typically occurs when a pump or valve keeps switching its status back and forth between successive iterations while solving the hydraulic equations for the network, thus causing the system to fail to converge to a solution.  Possible causes for this include a pair of pressure controls that turn a pump on and off whose pressure settings are too close together, or a collection of pressure regulating valves whose pressure settings influence the status of one another.  You can specify a Full Hydraulic Status report with the Simulation Report Options to identify those pipes in the Output File that might be behaving in this manner and then modify their pressure or flow settings to avoid this situation.  Another option, but less preferred, would be to use a slightly larger value for the model ACCURACY parameter, which can be set using the Edit Simulation Options command.

  • Negative Pressures exist at Node(s). InfoWater Pro will issue a warning message when it encounters negative pressures at junctions that have positive demands. This usually indicates that there is some problem with the way the network has been connected or operated. There is more demand than the system is able to supply. Negative pressures can occur when portions of the network can only receive water through pipes that have been closed or restricted. In such cases, an additional warning message about the network being disconnected is usually issued.

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