# Flow Control Valves

Calculation Error/Model Fails to Converge: Modelling multiple flow control valves in series can occasionally cause convergence errors due to the system becoming over-constrained. It is recommended that users give careful consideration to the positioning of flow controllers and the controlled flow rate. Design Note: It is recommended that flow control valves are not modeled in series with known/fixed flow boundary nodes or centrifugal pumps which are set to Automatically Size as this leads to duplication of defined system flow rates which may or over-constrain the model. If any of the above is unclear or you require any further information, please contact us at: support@fluidflowinfo.com.