The Library Verification window is displayed when you open a model or new scenario which contains connected library items that have some inconsistency.

1. Library Item Not Found

You may have a library item that is not found in any currently connected library. For example, a compressor may be connected to a library, and derive its data from that library. However, when the model is loaded, the source library is not available. This could be for several reasons that will be discussed shortly.

The compressor in the model does in fact have all of the required data needed to run the model. But when it is not found in the library, you will be offered several options:

• Disconnect it from the source library – this means that the model will forget the library the compressor came from and make it a standalone compressor not connected to any library.

• Add it to a library – this means that the compressor can be added to a custom library

• Leave the library connection – this means that the compressor will remember what library to which was originally connected and connect to that library again when it is made available to AFT Arrow. If, however, you try to open the compressor/fan Properties window, AFT Arrow will disconnect the compressor from the library and warn you.

The compressor might have lost its library connection for one of these reasons:

• The library is no longer available because it was removed either through the Library Manager or because your libraries have been changed on the network.

• The model is being run on a different PC than where it was created, and the original libraries are no longer available. This could be, for example, because you have moved the model onto a laptop computer to take it on travel. Or it could happen because the model was developed by another company which had developed libraries of its own but which are not available to you.

Whatever choice you make, the model will retain all its engineering data and yield the same results as it did originally.

2. Item in Model is Different from Library

You may have a library item in the model that is connected to an external library, but for some reason the data is not the same. For example, you may have a fan curve for the Rocky Mountain Fan Company's Model 100A in your model, but it does not match the fan curve for this model in your library. Here you have three choices:

• Update the items in the model to match the library – this will actually change the model's input data, and it might yield different results that originally

• Update the library (if it is local) to match the model's items – this will change the library, but will leave the model's input data as it was. It will yield the same results as it did previously.

• Disconnect it from the source library – this will leave the model as it was, and it will yield the same results.

The fan in the model might have a different fan curve than the one in the library for one of these reasons:

• When the model was built, the fan was connected to the Rocky Mountain Fan Company (i.e., RMFC) Model 100A. But since that time, the library has changed. Perhaps there was an input error in the original data, or better data has since become available and the library was updated. If this were the case, it would be best to update all your fans to the library values.

• The library may have been changed by an unauthorized individual, and while it was accurate originally, now the data is no longer valid. In this case, it would be best to not update the fan in your model, and to inquire into the cause of the inaccurate data within your organization.