diff --git a/src/finiteVolume/fields/fvPatchFields/derived/flowRateInletVelocity/flowRateInletVelocityFvPatchVectorField.C b/src/finiteVolume/fields/fvPatchFields/derived/flowRateInletVelocity/flowRateInletVelocityFvPatchVectorField.C
index b6dee1f195..2d800ba7d7 100644
--- a/src/finiteVolume/fields/fvPatchFields/derived/flowRateInletVelocity/flowRateInletVelocityFvPatchVectorField.C
+++ b/src/finiteVolume/fields/fvPatchFields/derived/flowRateInletVelocity/flowRateInletVelocityFvPatchVectorField.C
@@ -169,7 +169,7 @@ void Foam::flowRateInletVelocityFvPatchVectorField::updateValues
         Up -= nUp*n;
 
         // Remove any reverse flow
-        nUp = min(nUp, 0.0);
+        nUp = min(nUp, scalar(0));
 
         const scalar flowRate = flowRate_->value(t);
         const scalar estimatedFlowRate = -gSum(rho*(this->patch().magSf()*nUp));
diff --git a/src/finiteVolume/fields/fvPatchFields/derived/flowRateOutletVelocity/flowRateOutletVelocityFvPatchVectorField.C b/src/finiteVolume/fields/fvPatchFields/derived/flowRateOutletVelocity/flowRateOutletVelocityFvPatchVectorField.C
index cf331d9b7e..7bf6181194 100644
--- a/src/finiteVolume/fields/fvPatchFields/derived/flowRateOutletVelocity/flowRateOutletVelocityFvPatchVectorField.C
+++ b/src/finiteVolume/fields/fvPatchFields/derived/flowRateOutletVelocity/flowRateOutletVelocityFvPatchVectorField.C
@@ -160,7 +160,7 @@ void Foam::flowRateOutletVelocityFvPatchVectorField::updateValues
     Up -= nUp*n;
 
     // Remove any reverse flow
-    nUp = max(nUp, 0.0);
+    nUp = max(nUp, scalar(0));
 
     const scalar flowRate = flowRate_->value(t);
     const scalar estimatedFlowRate = gSum(rho*(this->patch().magSf()*nUp));
diff --git a/src/finiteVolume/fields/fvPatchFields/derived/matchedFlowRateOutletVelocity/matchedFlowRateOutletVelocityFvPatchVectorField.C b/src/finiteVolume/fields/fvPatchFields/derived/matchedFlowRateOutletVelocity/matchedFlowRateOutletVelocityFvPatchVectorField.C
index d01c77ec20..a40f6cdfe8 100644
--- a/src/finiteVolume/fields/fvPatchFields/derived/matchedFlowRateOutletVelocity/matchedFlowRateOutletVelocityFvPatchVectorField.C
+++ b/src/finiteVolume/fields/fvPatchFields/derived/matchedFlowRateOutletVelocity/matchedFlowRateOutletVelocityFvPatchVectorField.C
@@ -148,7 +148,7 @@ void Foam::matchedFlowRateOutletVelocityFvPatchVectorField::updateValues
     Up -= nUp*n;
 
     // Remove any reverse flow
-    nUp = max(nUp, 0.0);
+    nUp = max(nUp, scalar(0));
 
     // Lookup non-const access to velocity field
     volVectorField& U