Index: Ringtoets/Piping/src/Ringtoets.Piping.Data/PipingInput.cs
===================================================================
diff -u -re62502b93eb5144e00dcba97a69b6c6088b99656 -r06f68f0f847ca22a36b2b43b9c3cd82ebf60a629
--- Ringtoets/Piping/src/Ringtoets.Piping.Data/PipingInput.cs	(.../PipingInput.cs)	(revision e62502b93eb5144e00dcba97a69b6c6088b99656)
+++ Ringtoets/Piping/src/Ringtoets.Piping.Data/PipingInput.cs	(.../PipingInput.cs)	(revision 06f68f0f847ca22a36b2b43b9c3cd82ebf60a629)
@@ -104,12 +104,7 @@
             set
             {
                 var newEntryPoint = value.ToPrecision(entryPointL.NumberOfDecimalPlaces);
-
-                if (!double.IsNaN(exitPointL))
-                {
-                    ValidateEntryExitPoint(newEntryPoint, exitPointL);
-                }
-
+                ValidateEntryExitPoint(newEntryPoint, exitPointL);
                 ValidatePointOnSurfaceLine(newEntryPoint);
                 entryPointL = newEntryPoint;
             }
@@ -136,20 +131,15 @@
             set
             {
                 var newExitPoint = value.ToPrecision(exitPointL.NumberOfDecimalPlaces);
-
-                if (!double.IsNaN(entryPointL))
-                {
-                    ValidateEntryExitPoint(entryPointL, newExitPoint);
-                }
-
+                ValidateEntryExitPoint(entryPointL, newExitPoint);
                 ValidatePointOnSurfaceLine(newExitPoint);
                 exitPointL = newExitPoint;
             }
         }
 
         private void ValidateEntryExitPoint(RoundedDouble entryPoint, RoundedDouble exitPoint)
         {
-            if (entryPoint >= exitPoint)
+            if (!double.IsNaN(entryPoint) && !double.IsNaN(exitPoint) && entryPoint >= exitPoint)
             {
                 throw new ArgumentOutOfRangeException(null, Resources.PipingInput_EntryPointL_greater_or_equal_to_ExitPointL);
             }