diff --git a/src/regionModels/pyrolysisModels/reactingOneDim/reactingOneDim.C b/src/regionModels/pyrolysisModels/reactingOneDim/reactingOneDim.C
index e55dc74abb93a886dfa17b954c8fcb89668c1e0c..43a9e543af4bae06e9a772e9ba28dfd23399fd6a 100644
--- a/src/regionModels/pyrolysisModels/reactingOneDim/reactingOneDim.C
+++ b/src/regionModels/pyrolysisModels/reactingOneDim/reactingOneDim.C
@@ -622,7 +622,7 @@ scalar reactingOneDim::solidRegionDiffNo() const
         DiNum = max(KrhoCpbyDelta.primitiveField())*time().deltaTValue();
     }
 
-    return DiNum;
+    return returnReduce(DiNum, maxOp<scalar>());
 }