diff --git a/applications/solvers/multiphase/interFoam/alphaCourantNo.H b/applications/solvers/multiphase/interFoam/alphaCourantNo.H
index ffd039c77a..12d1b933d4 100644
--- a/applications/solvers/multiphase/interFoam/alphaCourantNo.H
+++ b/applications/solvers/multiphase/interFoam/alphaCourantNo.H
@@ -43,10 +43,10 @@ if (mesh.nInternalFaces())
         pos(alpha1 - 0.01)*pos(0.99 - alpha1)
        *fvc::surfaceSum(mag(phi))().internalField();
 
-    alphaCoNum = 0.5*max(sumPhi/mesh.V().field())*runTime.deltaT().value();
+    alphaCoNum = 0.5*gMax(sumPhi/mesh.V().field())*runTime.deltaT().value();
 
     meanAlphaCoNum =
-        0.5*(sum(sumPhi)/sum(mesh.V().field()))*runTime.deltaT().value();
+        0.5*(gSum(sumPhi)/gSum(mesh.V().field()))*runTime.deltaT().value();
 }
 
 Info<< "Interface Courant Number mean: " << meanAlphaCoNum
diff --git a/src/finiteVolume/cfdTools/compressible/compressibleCourantNo.H b/src/finiteVolume/cfdTools/compressible/compressibleCourantNo.H
index d8f7a6cbc0..73da862406 100644
--- a/src/finiteVolume/cfdTools/compressible/compressibleCourantNo.H
+++ b/src/finiteVolume/cfdTools/compressible/compressibleCourantNo.H
@@ -38,10 +38,10 @@ if (mesh.nInternalFaces())
         fvc::surfaceSum(mag(phi))().internalField()
        /rho.internalField();
 
-    CoNum = 0.5*max(sumPhi/mesh.V().field())*runTime.deltaT().value();
+    CoNum = 0.5*gMax(sumPhi/mesh.V().field())*runTime.deltaT().value();
 
     meanCoNum =
-        0.5*(sum(sumPhi)/sum(mesh.V().field()))*runTime.deltaT().value();
+        0.5*(gSum(sumPhi)/sum(mesh.V().field()))*runTime.deltaT().value();
 }
 
 Info<< "Courant Number mean: " << meanCoNum
diff --git a/src/finiteVolume/cfdTools/incompressible/CourantNo.H b/src/finiteVolume/cfdTools/incompressible/CourantNo.H
index 2d2e82ade1..caef48a396 100644
--- a/src/finiteVolume/cfdTools/incompressible/CourantNo.H
+++ b/src/finiteVolume/cfdTools/incompressible/CourantNo.H
@@ -37,10 +37,10 @@ if (mesh.nInternalFaces())
     scalarField sumPhi =
         fvc::surfaceSum(mag(phi))().internalField();
 
-    CoNum = 0.5*max(sumPhi/mesh.V().field())*runTime.deltaT().value();
+    CoNum = 0.5*gMax(sumPhi/mesh.V().field())*runTime.deltaT().value();
 
     meanCoNum =
-        0.5*(sum(sumPhi)/sum(mesh.V().field()))*runTime.deltaT().value();
+        0.5*(gSum(sumPhi)/sum(mesh.V().field()))*runTime.deltaT().value();
 }
 
 Info<< "Courant Number mean: " << meanCoNum