This feature allows you to validate your model against typical data entry errors, hard to detect topology problems, and modeling problems. When the Data Check button is selected, in the Run dialog box, the model is automatically validated before detailed calculations are begun. The process produces either a dialog box stating No Problems Found or a status log (see “Status Log” on page 12-539) with a list of messages. The data check algorithm performs the following validations:

• Network Topology—Checks that the network contains at least one boundary node, one pipe, and one junction, the minimum network requirements. It also checks for fully connected pumps and valves and that every node is reachable from a boundary node through open links.
• Element Validation—Checks that every element in the network is valid for the calculation. For example, this validation ensures that all pipes have nonzero length, nonzero diameter, etc. Each type of element has its own checklist. This same validation is performed when you edit an element in a dialog box.

The validation process generates two types of messages. A warning message means that a particular part of the model (e.g., a pipe’s roughness) does not conform to the expected value or is not within the expected range of values. This type of warning is useful but not fatal. Therefore, no corrective action is required to proceed with a calculation. Warning messages are often generated as a result of a topographical or data-entry error and should be corrected.

An error message, on the other hand, is a fatal error and the calculation cannot proceed before it is corrected. Typically, error messages are related to problems in the network topology, such as a pump or valves not being connected on both its intake and discharge sides.