diff --git a/applications/utilities/mesh/generation/foamyHexMesh/conformalVoronoiMesh/conformalVoronoiMesh/conformalVoronoiMeshIO.C b/applications/utilities/mesh/generation/foamyHexMesh/conformalVoronoiMesh/conformalVoronoiMesh/conformalVoronoiMeshIO.C
index b0da21cbbb..5b7612748c 100644
--- a/applications/utilities/mesh/generation/foamyHexMesh/conformalVoronoiMesh/conformalVoronoiMesh/conformalVoronoiMeshIO.C
+++ b/applications/utilities/mesh/generation/foamyHexMesh/conformalVoronoiMesh/conformalVoronoiMesh/conformalVoronoiMeshIO.C
@@ -962,7 +962,7 @@ void Foam::conformalVoronoiMesh::writeMesh
     (
         mesh,
         boundaryFacesToRemove,
-        orOp<bool>()
+        orEqOp<unsigned int>()
     );
 
     labelList addr(boundaryFacesToRemove.count());