diff --git a/src/thermophysicalModels/reactionThermo/mixtures/multiComponentMixture/multiComponentMixture.C b/src/thermophysicalModels/reactionThermo/mixtures/multiComponentMixture/multiComponentMixture.C
index 4e8d40faff180430f9e1f282d74bf8a22c488ef5..0414b0077e302973a42dcd37225aeb75594c0ddd 100644
--- a/src/thermophysicalModels/reactionThermo/mixtures/multiComponentMixture/multiComponentMixture.C
+++ b/src/thermophysicalModels/reactionThermo/mixtures/multiComponentMixture/multiComponentMixture.C
@@ -6,6 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2017 OpenFOAM Foundation
+    Copyright (C) 2021 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -59,13 +60,21 @@ void Foam::multiComponentMixture<ThermoType>::correctMassFractions()
         Yt += Y_[n];
     }
 
-    if (mag(max(Yt).value()) < ROOTVSMALL)
+    if (mag(min(Yt).value()) < ROOTVSMALL)
     {
         FatalErrorInFunction
             << "Sum of mass fractions is zero for species " << this->species()
             << exit(FatalError);
     }
 
+    if (mag(max(Yt).value()) != scalar(1))
+    {
+        WarningInFunction
+            << "Sum of mass fractions is different from one for species "
+            << this->species()
+            << nl;
+    }
+
     forAll(Y_, n)
     {
         Y_[n] /= Yt;
diff --git a/tutorials/combustion/fireFoam/LES/compartmentFire/0/N2 b/tutorials/combustion/fireFoam/LES/compartmentFire/0/N2
index af2cab4616cc1f50776e431c190a1dba84e2ed2e..1c54ddf0695a41498a3fac7474f375b0e802dfd2 100644
--- a/tutorials/combustion/fireFoam/LES/compartmentFire/0/N2
+++ b/tutorials/combustion/fireFoam/LES/compartmentFire/0/N2
@@ -24,7 +24,7 @@ boundaryField
     inlet
     {
         type            calculated;
-        value           uniform 0.76699;
+        value           uniform 0;
     }
     entrainment
     {
diff --git a/tutorials/combustion/fireFoam/LES/flameSpreadWaterSuppressionPanel/0/N2 b/tutorials/combustion/fireFoam/LES/flameSpreadWaterSuppressionPanel/0/N2
index df14991fc5945c44f24ebaaf5f08e2a0bec1e97c..322c1c51c39baa647803b5a071bd20075da42e92 100644
--- a/tutorials/combustion/fireFoam/LES/flameSpreadWaterSuppressionPanel/0/N2
+++ b/tutorials/combustion/fireFoam/LES/flameSpreadWaterSuppressionPanel/0/N2
@@ -43,7 +43,7 @@ boundaryField
     inlet
     {
         type            calculated;
-        value           $internalField;
+        value           uniform 0;
     }
 
     region0_to_pyrolysisRegion_coupledWall
diff --git a/tutorials/combustion/fireFoam/LES/oppositeBurningPanels/0/N2 b/tutorials/combustion/fireFoam/LES/oppositeBurningPanels/0/N2
index 8b2b4eb7240885accfdeb0b272f1cb52fd4654fd..2e97c7ef4012a34ebf5a8af915a77aadf82c07f4 100644
--- a/tutorials/combustion/fireFoam/LES/oppositeBurningPanels/0/N2
+++ b/tutorials/combustion/fireFoam/LES/oppositeBurningPanels/0/N2
@@ -40,7 +40,7 @@ boundaryField
     burner
     {
         type            calculated;
-        value           $internalField;
+        value           uniform 0;
     }
 
     "(region0_to.*)"
diff --git a/tutorials/combustion/fireFoam/LES/simplePMMApanel/0/N2 b/tutorials/combustion/fireFoam/LES/simplePMMApanel/0/N2
index 2bf2d847400d43beb9096fe04634e2865d3a3c47..f1967c47e8f21fe60961432e072594a50972fb6f 100644
--- a/tutorials/combustion/fireFoam/LES/simplePMMApanel/0/N2
+++ b/tutorials/combustion/fireFoam/LES/simplePMMApanel/0/N2
@@ -48,7 +48,8 @@ boundaryField
 
     region0_to_panelRegion_panel
     {
-        type            zeroGradient;
+        type            calculated;
+        value           uniform 0;
     }
 }
 
diff --git a/tutorials/combustion/fireFoam/LES/simplePMMApanel/0/O2 b/tutorials/combustion/fireFoam/LES/simplePMMApanel/0/O2
index 0dd4f49f062db59801b829eca55fd561a972fc5a..923aed5dbd565bc0cd7e0fe0d52411934cb36ba3 100644
--- a/tutorials/combustion/fireFoam/LES/simplePMMApanel/0/O2
+++ b/tutorials/combustion/fireFoam/LES/simplePMMApanel/0/O2
@@ -48,7 +48,8 @@ boundaryField
 
     region0_to_panelRegion_panel
     {
-        type            zeroGradient;
+        type            fixedValue;
+        value           uniform 0;
     }
 }
 
diff --git a/tutorials/combustion/fireFoam/LES/smallPoolFire2D/0/N2 b/tutorials/combustion/fireFoam/LES/smallPoolFire2D/0/N2
index 841b2c741fa0218ec60f8a765d0633ba66c1ad50..f0833ac8d6a0a220a696edb81f35dc4654794dd4 100644
--- a/tutorials/combustion/fireFoam/LES/smallPoolFire2D/0/N2
+++ b/tutorials/combustion/fireFoam/LES/smallPoolFire2D/0/N2
@@ -17,7 +17,7 @@ FoamFile
 
 dimensions      [0 0 0 0 0 0 0];
 
-internalField   uniform 0.76699;
+internalField   uniform 0.77;
 
 boundaryField
 {
@@ -36,7 +36,7 @@ boundaryField
     inlet
     {
         type            calculated;
-        value           $internalField;
+        value           uniform 0;
     }
 
     frontAndBack
diff --git a/tutorials/combustion/fireFoam/LES/smallPoolFire2D/0/O2 b/tutorials/combustion/fireFoam/LES/smallPoolFire2D/0/O2
index 34d7964dd779296d6c4d9239df180ff23877cfb4..c16e79c331ce174b9e6b54a6de021f08125f0ce6 100644
--- a/tutorials/combustion/fireFoam/LES/smallPoolFire2D/0/O2
+++ b/tutorials/combustion/fireFoam/LES/smallPoolFire2D/0/O2
@@ -17,7 +17,7 @@ FoamFile
 
 dimensions      [0 0 0 0 0 0 0];
 
-internalField   uniform 0.23301;
+internalField   uniform 0.23;
 
 boundaryField
 {
diff --git a/tutorials/combustion/fireFoam/LES/smallPoolFire3D/0/N2 b/tutorials/combustion/fireFoam/LES/smallPoolFire3D/0/N2
index e9c1c64659c670a320250d39eed15777ac67916e..735cb62c5b108c7e214398ab8db931e9da01a823 100644
--- a/tutorials/combustion/fireFoam/LES/smallPoolFire3D/0/N2
+++ b/tutorials/combustion/fireFoam/LES/smallPoolFire3D/0/N2
@@ -36,7 +36,7 @@ boundaryField
     inlet
     {
         type            calculated;
-        value           $internalField;
+        value           uniform 0;
     }
 }
 
diff --git a/tutorials/combustion/reactingFoam/laminar/counterFlowFlame2D/0/CH4 b/tutorials/combustion/reactingFoam/laminar/counterFlowFlame2D/0/CH4
index 92fe7b568da4247d64eb2f27301535f216eb6fbd..937e2fe75f0280bafcaab9d622d949fbd54600c7 100644
--- a/tutorials/combustion/reactingFoam/laminar/counterFlowFlame2D/0/CH4
+++ b/tutorials/combustion/reactingFoam/laminar/counterFlowFlame2D/0/CH4
@@ -23,7 +23,7 @@ boundaryField
     fuel
     {
         type            fixedValue;
-        value           uniform 1;
+        value           uniform 10;
     }
 
     air
@@ -36,7 +36,7 @@ boundaryField
     {
         type            inletOutlet;
         inletValue      uniform 0;
-        value           uniform 0;
+        value           uniform 1;
     }
 
     frontAndBack
diff --git a/tutorials/combustion/reactingFoam/laminar/counterFlowFlame2D/0/N2 b/tutorials/combustion/reactingFoam/laminar/counterFlowFlame2D/0/N2
index 1b709fad89c9b471c9474fcf4857fc43ca8f5871..0cc0abbf41b81342ac86788525b968efbf64a01d 100644
--- a/tutorials/combustion/reactingFoam/laminar/counterFlowFlame2D/0/N2
+++ b/tutorials/combustion/reactingFoam/laminar/counterFlowFlame2D/0/N2
@@ -35,8 +35,8 @@ boundaryField
     outlet
     {
         type            inletOutlet;
-        inletValue      uniform 1;
-        value           uniform 1;
+        inletValue      uniform 0;
+        value           uniform 0;
     }
 
     frontAndBack