diff --git a/src/main/python/utils/UnitOperations.py b/src/main/python/utils/UnitOperations.py
index 353da9a..671b78b 100644
--- a/src/main/python/utils/UnitOperations.py
+++ b/src/main/python/utils/UnitOperations.py
@@ -104,13 +104,9 @@ def OM_Flowsheet_Initialize(self):
         self.OM_data_init = ''
 
         if(self.thermo_pack_req):
-            if len(self.extra)>1:   
-                for i in range(len(self.extra)):
-                    latest = ''
-                    for j in range(self.extra[i]):
-                        if self.extra[i][j]!='.':
-                            latest += self.extra[i][j]
-                        self.for_naming[i] = latest   
+            if len(self.extra)>1:
+                # Modelica model names cannot contain '.', e.g. 'DistillationColumn.Cond'
+                self.for_naming = [e.replace('.', '') for e in self.extra]
 
         if(self.thermo_pack_req):
             if len(self.extra)==1:
@@ -133,10 +129,9 @@ def OM_Flowsheet_Initialize(self):
                         self.OM_data_init += ('extends Simulator.UnitOperations.'+self.extra[i]+';\n')
                         for j in range(len(self.extra)-1):
                             self.OM_data_init += (self.for_naming[j] + str(self.counter) +' ' + self.for_naming[j] + '#' + self.multidict[j] + ';\n')
+                        self.OM_data_init += ('end '+self.for_naming[i]+str(self.counter)+';\n')
 
-                            self.OM_data_init += ('end '+self.for_naming[i]+str(self.counter)+';\n')
-
-                    self.OM_data_init += self.for_naming[i] + str(self.counter) + ' ' + self.for_naming + '(Nc = ' + str(len(self.compounds))
+                self.OM_data_init += self.for_naming[-1] + str(self.counter) + ' ' + self.name + '(Nc = ' + str(len(self.compounds))
                  
             C = ', '.join(_normalize_compound_name(c) for c in self.compounds)
             self.OM_data_init += ',C = {' + C + '}'  
@@ -426,9 +421,12 @@ def OM_Flowsheet_Equation(self):
             self.OM_data_eqn = self.OM_data_eqn + (self.output_stms[1].name + '.F_pc[1,:' +
                                str(self.compounds.index(self.variables['C_Spec']['comp']) + 1) + '] = ' + str(
                                self.variables['C_Spec']['value']) + ';\n')
-        else:
+        elif self.mode:
             self.OM_data_eqn = self.OM_data_eqn + (
-                    self.name + '.Condenser.' + self.mode + '=' + str(self.modeVal) + ';\n')
+                    self.name + '.condenser.' + self.mode + '=' + str(self.mode_val) + ';\n')
+        else:
+            raise ValueError(
+                "Unsupported condenser specification: " + str(self.variables['C_Spec']['type']))
 
         if self.variables['R_Spec']['type'] == "Product Molar Flow   (mol/s)":
             self.OM_data_eqn = self.OM_data_eqn + (self.output_stms[2].name + '.' + 'F_p[1] = ' + str(
diff --git a/tests/test_unit_operations.py b/tests/test_unit_operations.py
index 64ff62a..190ab47 100644
--- a/tests/test_unit_operations.py
+++ b/tests/test_unit_operations.py
@@ -1,15 +1,17 @@
 import sys
 import os
 import unittest
+from types import SimpleNamespace
 
 # Ensure Python can find modules under src/main/python
 sys.path.insert(0, os.path.abspath(os.path.join(os.path.dirname(__file__), '..', 'src', 'main', 'python')))
 
 from utils.UnitOperations import (
-    Mixer, Splitter, Heater, Cooler, Flash, CentrifugalPump, Valve,
+    UnitOperation, Mixer, Splitter, Heater, Cooler, Flash, CentrifugalPump, Valve,
     AdiabaticCompressor, AdiabaticExpander, CompoundSeparator,
     ShortcutColumn, DistillationColumn, ConvertionReactor
 )
+from python.utils.ComponentSelector import compound_selected
 
 
 class TestUnitOperations(unittest.TestCase):
@@ -172,5 +174,56 @@ def test_conversion_reactor_initialization(self):
         self.assertEqual(reactor.no_of_outputs, 1)
 
 
+class TestUnitOperationCodeGeneration(unittest.TestCase):
+    """Regression tests for Modelica code paths that used to crash."""
+
+    def setUp(self):
+        self._saved_compounds = list(compound_selected)
+        compound_selected[:] = ["Water(chemsep)", "Ethanol(chemsep)"]
+
+    def tearDown(self):
+        compound_selected[:] = self._saved_compounds
+
+    def test_initialize_with_multiple_thermo_models(self):
+        unit = UnitOperation()
+        unit.name = 'U1'
+        unit.thermo_pack_req = True
+        unit.extra = ['DistillationColumn.Cond', 'DistillationColumn.DistCol']
+        unit.multidict = ['x']
+        unit.parameters = ['Nt']
+        unit.variables = {'Nt': {'value': 12}}
+        c = UnitOperation.counter
+
+        self.assertEqual(
+            unit.OM_Flowsheet_Initialize(),
+            f'model DistillationColumnCond{c}\n'
+            'extends Simulator.UnitOperations.DistillationColumn.Cond;\n'
+            'extends Simulator.Files.ThermodynamicPackages.RaoultsLaw;\n'
+            f'end DistillationColumnCond{c};\n'
+            f'model DistillationColumnDistCol{c}\n'
+            'extends Simulator.UnitOperations.DistillationColumn.DistCol;\n'
+            f'DistillationColumnCond{c} DistillationColumnCond#x;\n'
+            f'end DistillationColumnDistCol{c};\n'
+            f'DistillationColumnDistCol{c} U1(Nc = 2,C = {{Water, Ethanol}}, Nt = 12);\n',
+        )
+
+    def _column_with_condenser_spec(self, spec):
+        column = DistillationColumn()
+        column.variables['C_Spec']['type'] = spec
+        column.input_stms = {1: SimpleNamespace(name='F')}
+        column.output_stms = {1: SimpleNamespace(name='D'), 2: SimpleNamespace(name='B')}
+        return column
+
+    def test_condenser_fallback_uses_selected_mode(self):
+        column = self._column_with_condenser_spec('Custom')
+        column.mode, column.mode_val = 'T', 350
+        self.assertIn(f'{column.name}.condenser.T=350;\n', column.OM_Flowsheet_Equation())
+
+    def test_unknown_condenser_spec_without_mode_raises(self):
+        column = self._column_with_condenser_spec('Custom')
+        with self.assertRaisesRegex(ValueError, 'Unsupported condenser specification: Custom'):
+            column.OM_Flowsheet_Equation()
+
+
 if __name__ == '__main__':
     unittest.main()