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When the model error is indicated on a basic circuit, there are two types of indicators. Red means it's an error, Yellow means it's a warning. By hoovering with the mouse cursor over the respective node or basic circuit, an explanation of the inconsistency or error/warning appears.
The figures below illustrate some typical examples of model errors.
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'Dead end node' means that this model is not complete. This pipe segment needs to be connected with a basic circuit.
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The basic circuit of the pump indicates there is a warning called 'Pumps found downstream of this pump'. Which means that ther're several pumps in series.
The color of the active mixing basic circuit indicates there is an error called 'Pump in variable part of mixing ciruit'. For the proper operation of the active mixing circuit, a primary pump should not be placed before mixing circuit..
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This basic circuit indicates that this 'base circuit is reversed' which means that the entry and exit of the base circuit is installed in the opposite way.