diff --git a/buildingspy/CHANGES.txt b/buildingspy/CHANGES.txt
index b77e0464..51e23a2f 100644
--- a/buildingspy/CHANGES.txt
+++ b/buildingspy/CHANGES.txt
@@ -3,6 +3,8 @@ BuildingsPy Changelog
 
 Version 5.2.1, ...
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+- In buildingspy/development/regressiontest.py, added detection of unit propagation error in Dymola.
+  (https://github.com/lbl-srg/BuildingsPy/issues/620)
 - In buildingspy/development/regressiontest.py, changed MODELICAPATH on Windows to use ';' instead of ':'
   (https://github.com/lbl-srg/BuildingsPy/issues/609)
 - Updated pyfunnel to version 2.0.1 to fix plotting issues.
diff --git a/buildingspy/development/regressiontest.py b/buildingspy/development/regressiontest.py
index ccfada0e..55e40c04 100644
--- a/buildingspy/development/regressiontest.py
+++ b/buildingspy/development/regressiontest.py
@@ -3267,6 +3267,7 @@ def _print_end_of_json(isLastItem, fileHandle, logFileName):
 Evaluate=false;
 Advanced.CompileWith64=2;
 Advanced.EfficientMinorEvents=false;
+Advanced.Translation.Log.UnitPropagationFailure=20;
 // Set the pedantic Modelica mode
 Advanced.PedanticModelica = {str(self._pedanticModelica).lower()};
 orig_Advanced_GenerateVariableDependencies = Advanced.GenerateVariableDependencies;