A number of warnings may be given in the output when you run AFT Impulse's Solver. These warnings are intended to alert you about potential problems with the model or solution. Some warnings may prove to be harmless upon closer inspection, but you should never ignore them.There are different warning levels depending on the importance of the warning.

1. CRITICAL WARNING A critical warning is very important and reflects a high possibility of incorrect results in the output2. WARNING A warning that actually says WARNING offers important information about the converged solution or the model itself. The information should always be reviewed.3. CAUTION A cautionary warning is of less importance than a full warning. The included information may or may not be of interest to the user.4. Design Alert Warnings When a pipe exceeds a users design alert a notification is given.

The following is a complete list of the warnings you may receive, with a brief explanation given of each. Whenever any warnings occur that are WARNING or CRITICAL WARNING level, the General Results section of the Output Window will be displayed with the text in red.

CAUTIONS Assigned Flow at Junction X has a constant flow rate during the transient... Check Valve closed at Junction X Flow is negative through Junction X. Loss factors may be in error Head loss, head rise, hydraulic gradeline and energy gradeline output does not have meaning for zero g systems Head rise across fixed flow pumps is referenced to system g level... Junction X exceeded maximum event messages Junction X has a density change across it. If this is due to a moving interface... Pipe X length is shorter than the elevation change (between Junction Y and Z) Pipe X segment length Y is shorter than the elevation change. Pump with Check Valve closed at Junction X Some four quadrant data was based on estimated, not measured, data. Predicted results may not be accurate. Transient data did not extend to Stop Time at Junction X

WARNINGS Chempak temperature and/or pressure is out of range for the following Effective Reynolds exceeds max Reynolds number in Pipe X FCV could not control flow at Junction X Flow may not be balanced at Junction X Flow is into system at Reservoir Junction X... HGL, EGL and head loss results may not be meaningful for variable density systems. Junction X cavitates. Cavitation at vacuum breaker valve junctions can cause anomalous results which may be incorrect. Junction X Exceeded Runout Flow Rate... Junction X Has Insufficient Pump NPSH/ NPSP... Junction X Pump Added Negative Pressure Pipe force calculations are not reliable when cavitation occurs during the simulation Pipe X completely drained at Y seconds. Predicted results are not reliable after this time. PRV could not control pressure at Junction X PSV could not control pressure at Junction X Static pressure lower than vapor pressure at inlet/outlet of pipe X Surge Tank junction X completely drained at Y seconds. Predicted results are not reliable after this time. Temperature at inlet of pipe X is above/below max/min fluid temperature range The pipes listed below use constant friction factors during the transient analysis... Transient data was extrapolated at Junction X Transient static pressure lower than vapor pressure at Pipe X Station Y Unique solution not possible - Relief valve cycles Vacuum Breaker Valve Junction X steady-state pressure Y is below cracking pressure Z

CRITICAL WARNINGS Artificial Transient - Initial pressure conditions at Pipe X Station Y are not steady (Error = Z%) FCV/PRV/PSV Could Not Control Flow/Pressure - Pressure Was Added... Junction X cavitates. Cavitation at vacuum breaker valve junctions can cause anomalous results which may be incorrect. Junction X Had Reverse Flow - Pump Head Could Not Be Predicted Setting relaxation lower than relative pressure/flow tolerance gives unreliable results These results do not represent a converged solution. Use only for error resolution purposes

Related TopicsTroubleshooting ModelsSteady Solution Control Window

Warnings and Cautions in Output

Page 1 of 1Warnings and Cautions in Output

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