What Do These Messages Mean and How Can I Fix Them?

You have created your model and verified all the data that you have entered, but when you calculate your model you find that you have several warning messages. What do you do now? 

PIPE-FLO® Professional and Flow of Fluids come with a wide variety of messages that can be triggered by many different situations. Both programs have 5 levels of messages that increase in severity as the message level decreases. In addition, the messages come with alert icons that display the severity of the message. 

The most severe message that the software can give is a Level 0. This message has an alert icon that looks as follows: If you encounter a Level 0 message, no calculations can be performed because these messages are pre-calculation checks, or calculation engine error messages that prevent the program from calculating. The pre-calculation checks scour the system for invalid data and to verify a sufficient amount of data exists for the calculations to proceed. If Level 0 messages are given upon calculation, then no other calculation messages will be present until the Level 0 messages have been cleared.

The next most severe message that can be given in a system model is a Level 1 message. This message will have a very similar icon as Level 0 messages, however, Level 1 warnings allow calculations to be performed. Level 1 messages are based on calculated results that are invalid or a system configuration that is invalid. These messages mean that the results are wrong and require close evaluation. Some of the most widely seen of these messages are “Set point cannot be achieved since a pressure gain across the valve was calculated” and “Set flow rate cannot be achieved, a pressure drop across the pump was calculated”. Both of these messages are Level 1 messages because the calculated result (pressure drop) is not typical for the device. For example, a pump is typically used to add pressure to a system and not remove pressure from the system. Therefore, the message was thrown to warn the user that the pump is not acting correctly within the system. 

Level 2 messages are not as severe and are based on calculated results that exceed limits of equipment, limits of the equations used for the results or input data uncertainties. The alert icon for this message is as follows: 

These messages typically mean that there is an increased uncertainty with regards to the accuracy of the calculated result associated. The calculated result should be verified to be sure it is correct. An example of a Level 2 message is: “Pressure ratio is beyond the limits of the standard, results may be inaccurate”; all this message is saying is that the pressure ratio is outside the valid range that the standard provides and the calculated result needs to be verified.

The next message level available is a Level 3 message. Level 3 messages are messages that are based on calculations that exceed specified operation limits. Therefore, if a Level 3 message is present in your message window, it means that the calculated result is outside a limit that was defined by you. The alert icon for this message is very similar to the one for Level 2 messages. An example of a Level 3 message is displayed above, “Reverse flow”. This message warns that the fluid flowing in the pipeline is flowing in the opposite direction than it was drawn. 

The final message level that you, as the user, can receive is a Level 4 message. These messages are informational messages that may or may not be based on calculated results. Level 4 messages provide information about the status of devices, such as isolated devices and laminar flow conditions. There is a Level 4 message that will always be present in the message window when the model is calculated. This message is “Calculation complete. Number of iterations and % deviation for the last 5 iterations: #iterations {last iteration %Dev, 2nd to last iteration %Dev,…5th to last iteration %Dev}”. This message is an important one because it tells you if your model has converged to a solution along with the number of iterations it took to converge to a solution. If you have not converged to a solution, you will not only have reached your maximum iterations and your percent deviation will not be below 0.01%, but you will also receive a message stating “Percent Tolerance not achieved, results may not be accurate”. This is a Level 1 message that means the calculation engine has not converged to a solution within the specified Percent Tolerance after reaching the Maximum Number of Iterations specified in the Calculation Settings for the project.

Now that we have covered what the level of messages mean, what should you do when you get one of these messages? If you are within the support hours (Monday through Friday, excluding holidays, 7:30 a.m. to 4:00 p.m. Pacific Time), you can email in your model and we can assist you in deciphering what the messages mean and give you possible solutions to your messages. However, what happens if it is after support hours and your project is due the next day? Each message not only comes with the level, icon and a description of the message, but all messages come with a Help ID number that links directly to the help file. In the help file you will find the message, the level of the message, a description of what is causing the message and in many instances there will also be a fix to the error message as well. Please see an example below: 

For the message above, all you would need to do is right click the pipe that is giving the “Reverse Flow” message and choose “Reverse Flow Direction” if the pipe is truly flowing in the direction that the software says it is. If the pipe is not flowing in that direction, then you will need to evaluate the pressures in your system in case there is bigger issue.