diff --git a/src/geouned/GEOUNED/Write/WriteFiles.py b/src/geouned/GEOUNED/Write/WriteFiles.py
index 80bd75ca..64d45cd4 100644
--- a/src/geouned/GEOUNED/Write/WriteFiles.py
+++ b/src/geouned/GEOUNED/Write/WriteFiles.py
@@ -9,6 +9,15 @@ def writeGeometry(UniverseBox, MetaList, Surfaces, code_setting):
 
     baseName = code_setting["geometryName"]
 
+    # Currently there are two was of setting outFormat (via a .set method and
+    # a class attribute. Once we have a single method then move this validating
+    # input code to the attribute @setter
+    supported_mc_codes = ('mcnp', 'openMC_XML', 'openMC_PY', 'serpent', 'phits')
+    for out_format in code_setting['outFormat']:
+        if out_format not in supported_mc_codes:
+            msg = f'outFormat {out_format} not in supported MC codes ({supported_mc_codes})'
+            raise ValueError(msg)
+
     # write cells comments in file
     if code_setting["cellCommentFile"]:
         OutFiles.commentsWrite(baseName, MetaList)
diff --git a/tests/test_convert.py b/tests/test_convert.py
index ce569b1d..d890a4b4 100644
--- a/tests/test_convert.py
+++ b/tests/test_convert.py
@@ -22,7 +22,7 @@ def test_conversion(input_step_file):
         "title" : 'Input Test' ,
         "stepFile" : f"{input_step_file.resolve()}" ,
         "geometryName" : f"{output_filename_stem.resolve()}" ,
-        "outFormat" : ('mcnp', 'openMC_XML') ,
+        "outFormat" : ('mcnp', 'openMC_XML', 'openMC_PY', 'serpent', 'phits'),
         "compSolids" : False ,
         "volCARD" : False ,
         "volSDEF" : True ,
@@ -39,9 +39,10 @@ def test_conversion(input_step_file):
         "nPlaneReverse" : 0 ,
     }
 
-    # deletes the output openmc and mcnp output files if it already exists
-    output_filename_stem.with_suffix(".mcnp").unlink(missing_ok=True)
-    output_filename_stem.with_suffix(".xml").unlink(missing_ok=True)
+    # deletes the output MC files if they already exists
+    suffixes = ('.mcnp', '.xml', '.inp', '.py', '.serp')
+    for suffix in suffixes:
+      output_filename_stem.with_suffix(suffix).unlink(missing_ok=True)
 
     GEO = CadToCsg('Input Test')
 
@@ -51,5 +52,5 @@ def test_conversion(input_step_file):
 
     GEO.Start()
 
-    assert output_filename_stem.with_suffix(".mcnp").exists()
-    assert output_filename_stem.with_suffix(".xml").exists()
+    for suffix in suffixes:
+      assert output_filename_stem.with_suffix(suffix).exists()