Hallo,

the model Modelica.Fluid.Examples.HeatingSystem does not work at my PC (Win7, Xeon).

The warning is:
Iteration variables with default zero start attribute in torn nonlinear equation system:
         $DER.tank.ports[2].p:DUMMY_DER(flow=false fixed = false )  "Thermodynamic pressure in the connection point" type: Real  [2]
         $DER.pump.medium.h:DUMMY_DER(fixed = false )  "Specific enthalpy of medium" type: Real

The symbolic error is:
Das Modell ist strukturell singul�r. Fehler wurde gefunden durch Sortieren der Gleichungen
35: $cse27 = Modelica.Media.Water.IF97_Utilities.waterBaseProp_ph(pump.p_b_nominal, pump.medium.h, 0, 0);
34: heater.statesFM[1].T = Modelica.Media.Water.IF97_Utilities.T_props_ph(pump.p_b_nominal, pump.medium.h, $cse27);
...

The error is:
Interner Fehler Transformation Module PFPlusExt index Reduction Method Pantelides failed!
[C:/OM112/OpenModelica64bit/OMCompiler/Compiler/SimCode/SimCodeUtil.mo: 4354:9-4354:59]: Interner Fehler function createStateSetsSets failed.
[C:/OM112/OpenModelica64bit/OMCompiler/Compiler/SimCode/SimCodeUtil.mo: 596:5-596:146]: Interner Fehler function createSimCode failed [Transformation from optimised DAE to simulation code structure failed]

It seems that the tank may have a failure but I am not sure. But the example should work.

Hope for hints.
Peter