# Page History

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These are the messages associated with control valves:

ID | Message | Cause |
---|---|---|

110 | Set pressure < absolute zero | A Tank, Pressure Boundary, or a Control Valve or Sizing Valve set to PCV or BPV has a Set Pressure that is less than absolute zero. |

114 | Calculated static pressure < absolute zero | The calculated Static Pressure at the end of a Pipe connected to any Device is less than absolute zero. |

115 | Fluid changes state, static pressure < fluid vapor pressure | The Fluid Zone associated with a Device is a Liquid and the Static Pressure at that Device is calculated to be less than the Vapor Pressure of the Fluid Zone. |

116 | Fluid changes state, static pressure > fluid vapor pressure | The Fluid Zone associated with the Device is a gas and the static pressure at the inlet or outlet of the Device is greater than the Vapor Pressure of the Fluid Zone. |

119 | Pressure is outside of the specification design limits of the attached pipe | For any Device's inlet or outlet Pressure for either the Design value or Calculated result: If calculated pressure > pressure max design limit ORcalculated pressure < pressure min design limit. |

125 | Set flow rate cannot be achieved, a pressure gain across the valve was calculated | A Sizing Valve or Control Valve is set to FCV Operation and the Pressure Drop is calculated < 0. There is insufficient pressure at the valve inlet to create a pressure drop across the valve. |

132 | Calculated pressure drop is outside of the allowable dP range | A Sizing Valve or Control Valve has a calculated dP < minimum allowable dP OR calculated dP > maximum allowable dP. |

157 | Choked flow through the device | For designed Control Valves, the Calculated dP ≥ dP choked |

158 | Requires a flow coefficient greater than the 100% position to satisfy the operating conditions | For designed Control Valves, the calculated Flow Coefficient is greater than the Flow Coefficient at 100% position, indicating the Control Valve is sized too small. There is no Flow Coefficient result in this case. |

159 | Requires a flow coefficient less than the 1% position to satisfy the operating conditions | For designed Control Valves, the calculated Flow Coefficient is less than the Flow Coefficient at 1% position. The reported Flow Coefficient in this case is an estimated value. |

160 | The flow coefficient may not be correct, multiple solutions were found | For designed Control Valves with a liquid Fluid Zone, when the Flow Rate results in a Reynolds Number at the lower end of the transitional flow regime, multiple solutions may be found for the Flow Coefficient. The first solution found in this case is given as the result. |

161 | Invalid FP value was calculated, FP = 1 was used for the valve calculations | For Control Valves, for situations in which the Inlet Pipe Diameter equals the Valve Diameter, but is smaller than the Outlet Pipe Diameter, and theFlow Coefficient is sufficiently high, an invalid Piping Geometry Factor (FP) value may be calculated due to the square root of a negative number. Make inlet and outlet pipes the same size, even if they are not the same in the field. Give the incorrect pipe size an insignificant length, then attach the correct pipe size. |

162 | The Cv/d^2 Limit is exceeded, increased uncertainty in calculated results. | The ISA and IEC standards used for Control Valve calculations state that reasonable accuracy can only be maintained using the equations in the standard if Cv / (645 d^{2}) < 0.047 with diameter in inches. |

163 | Valve size > pipe size | For designed Control Valves, the entered Valve Size is greater than the Pipe Nominal Size (inlet and/or outlet pipe). This is something that is not normally done in practice, and it can also result in invalid results due to taking the square root of a negative number. |

164 | FL data is missing, this is required to perform liquid calculations for a valve | For a Control Valve, the Liquid Pressure Recovery (F) data has not been entered and the Fluid Zone is a liquid. _{L}F data is required for some of the calculations for a Control Valve._{L} |

165 | xT data is missing, this is required to perform gas calculations for a valve | For a Control Valve, the Choked Pressure Differential Ratio Factor (x) data has not been entered and the Fluid Zone is a gas. _{T}x data is required for some of the calculations for a Control Valve._{T} |

168 | Invalid xTP value was calculated. | For a Control Valve used in compressible gas application, the calculated xTP <= 0.0 or xTP >= 1.0. In this situation, a value 0.95 is assumed for xTP. |

169 | Valve calculation may be invalid | Any control vavle calculation in which an intermediate parameter is invalid for subsequent calculations. It is recommended to contact support if this message is encountered. |

170 | Deviation at the Device > Allowable Deviation. Consider adjusting Calculation Settings. | Systems with large flow rate ratio (between highest and smallest flow) push the deviation to the device(s) with the lowest flow rate. This could result in high deviation at the device, even if the model converges. Close evaluation of the results will allow the user to determine if this deviation is acceptable. Decreasing the % Tolerance Calculation Setting may reduce the deviation, but may result in the model not converging to a solution. |

### Version 2009 and Before

Operating Like a Pump – Flow cannot be achieved: This warning occurs when a flow control valve is set to an automatic set value that is higher than what the flow would be without a control valve. The valve is operating like a pump because it has to put energy into the system to achieve that flow rate.

Calculated dP is Outside of Allowable Range: This warning occurs when PIPE-FLO calculates the pressure drop across the control valve to be outside the allowable dP range specified by the user in the Control Valve dialog box.