diff --git a/src/Mod/Fem/CMakeLists.txt b/src/Mod/Fem/CMakeLists.txt
index a1f3530e71..0227fb21be 100755
--- a/src/Mod/Fem/CMakeLists.txt
+++ b/src/Mod/Fem/CMakeLists.txt
@@ -194,6 +194,7 @@ SET(FemSolverCalculix_SRCS
     femsolver/calculix/con_fixed.py
     femsolver/calculix/con_force.py
     femsolver/calculix/con_heatflux.py
+    femsolver/calculix/con_initialtemperature.py
     femsolver/calculix/con_planerotation.py
     femsolver/calculix/con_pressure.py
     femsolver/calculix/con_sectionprint.py
diff --git a/src/Mod/Fem/femsolver/calculix/con_initialtemperature.py b/src/Mod/Fem/femsolver/calculix/con_initialtemperature.py
new file mode 100644
index 0000000000..7b4bd8f94e
--- /dev/null
+++ b/src/Mod/Fem/femsolver/calculix/con_initialtemperature.py
@@ -0,0 +1,50 @@
+# ***************************************************************************
+# *   Copyright (c) 2021 Bernd Hahnebach <bernd@bimstatik.org>              *
+# *                                                                         *
+# *   This file is part of the FreeCAD CAx development system.              *
+# *                                                                         *
+# *   This program is free software; you can redistribute it and/or modify  *
+# *   it under the terms of the GNU Lesser General Public License (LGPL)    *
+# *   as published by the Free Software Foundation; either version 2 of     *
+# *   the License, or (at your option) any later version.                   *
+# *   for detail see the LICENCE text file.                                 *
+# *                                                                         *
+# *   This program is distributed in the hope that it will be useful,       *
+# *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
+# *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
+# *   GNU Library General Public License for more details.                  *
+# *                                                                         *
+# *   You should have received a copy of the GNU Library General Public     *
+# *   License along with this program; if not, write to the Free Software   *
+# *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  *
+# *   USA                                                                   *
+# *                                                                         *
+# ***************************************************************************
+
+__title__ = "FreeCAD FEM calculix constraint initialtemperature"
+__author__ = "Bernd Hahnebach"
+__url__ = "https://www.freecadweb.org"
+
+
+def get_analysis_types():
+    return ["thermomech"]
+
+
+def get_constraint_title():
+    return "Initial temperature constraint"
+
+
+def get_before_write_constraint():
+    return "*INITIAL CONDITIONS,TYPE=TEMPERATURE\n"
+
+
+def get_after_write_constraint():
+    return ""
+
+
+def write_constraint(f, femobj, inittemp_obj, ccxwriter):
+
+    f.write("{0},{1}\n".format(ccxwriter.ccx_nall, inittemp_obj.initialTemperature))
+
+
+# Should only be one object in the analysis
diff --git a/src/Mod/Fem/femsolver/calculix/writer.py b/src/Mod/Fem/femsolver/calculix/writer.py
index e4776b3033..332c12ded1 100644
--- a/src/Mod/Fem/femsolver/calculix/writer.py
+++ b/src/Mod/Fem/femsolver/calculix/writer.py
@@ -44,6 +44,7 @@ from . import con_displacement
 from . import con_fixed
 from . import con_force
 from . import con_heatflux
+from . import con_initialtemperature as con_initialtemp
 from . import con_planerotation
 from . import con_pressure
 from . import con_sectionprint
@@ -210,7 +211,7 @@ class FemInputWriterCcx(writerbase.FemInputWriter):
 
         # materials and fem element types
         self.write_materials(inpfile)
-        self.write_constraints_initialtemperature(inpfile)
+        self.write_constraints_data(inpfile, self.initialtemperature_objects, con_initialtemp)
         # self.write_femelement_geometry(inpfile)
         self.write_femelementsets(inpfile)
 
@@ -364,23 +365,6 @@ class FemInputWriterCcx(writerbase.FemInputWriter):
         if write_after != "":
             f.write(write_after)
 
-    # ********************************************************************************************
-    # constraints initialtemperature
-    def write_constraints_initialtemperature(self, f):
-        if not self.initialtemperature_objects:
-            return
-        if self.analysis_type not in ["thermomech"]:
-            return
-
-        # write constraint to file
-        f.write("\n***********************************************************\n")
-        f.write("** Initial temperature constraint\n")
-        f.write("*INITIAL CONDITIONS,TYPE=TEMPERATURE\n")
-        for itobj in self.initialtemperature_objects:  # Should only be one
-            inittemp_obj = itobj["Object"]
-            # OvG: Initial temperature
-            f.write("{0},{1}\n".format(self.ccx_nall, inittemp_obj.initialTemperature))
-
     # ********************************************************************************************
     # handle elements for constraints fluidsection with Liquid Inlet or Outlet
     # belongs to write_constraints_fluidsection, should be next method
diff --git a/src/Mod/Fem/femtest/data/calculix/thermomech_bimetall.inp b/src/Mod/Fem/femtest/data/calculix/thermomech_bimetall.inp
index 337ccada1a..0eaddf774e 100644
--- a/src/Mod/Fem/femtest/data/calculix/thermomech_bimetall.inp
+++ b/src/Mod/Fem/femtest/data/calculix/thermomech_bimetall.inp
@@ -8204,6 +8204,7 @@ Evolumes
 ***********************************************************
 ** Initial temperature constraint
 *INITIAL CONDITIONS,TYPE=TEMPERATURE
+** ConstraintInitialTemperature
 Nall,273.0
 
 ***********************************************************
diff --git a/src/Mod/Fem/femtest/data/calculix/thermomech_spine.inp b/src/Mod/Fem/femtest/data/calculix/thermomech_spine.inp
index 41e21bf692..f4bd019240 100644
--- a/src/Mod/Fem/femtest/data/calculix/thermomech_spine.inp
+++ b/src/Mod/Fem/femtest/data/calculix/thermomech_spine.inp
@@ -124,6 +124,7 @@ Evolumes
 ***********************************************************
 ** Initial temperature constraint
 *INITIAL CONDITIONS,TYPE=TEMPERATURE
+** FemConstraintInitialTemperature
 Nall,300.0
 
 ***********************************************************