diff --git a/src/functionObjects/solvers/scalarTransport/scalarTransport.C b/src/functionObjects/solvers/scalarTransport/scalarTransport.C
index 84b68341d8d1325d905127761678be8c9277ffd4..641241b91e6cbb2a7e6fd8c64bf966aa0e53eb28 100644
--- a/src/functionObjects/solvers/scalarTransport/scalarTransport.C
+++ b/src/functionObjects/solvers/scalarTransport/scalarTransport.C
@@ -201,7 +201,7 @@ Foam::functionObjects::scalarTransport::scalarTransport
     resetOnStartUp_(false),
     schemesField_("unknown-schemesField"),
     fvOptions_(mesh_),
-    bounded01_(dict.lookupOrDefault<bool>("bounded01", true))
+    bounded01_(dict.lookupOrDefault<Switch>("bounded01", true))
 {
     read(dict);
 
@@ -235,12 +235,7 @@ bool Foam::functionObjects::scalarTransport::read(const dictionary& dict)
     dict.readIfPresent("bounded01", bounded01_);
 
     schemesField_ = dict.lookupOrDefault("schemesField", fieldName_);
-
-    constantD_ = false;
-    if (dict.readIfPresent("D", D_))
-    {
-        constantD_ = true;
-    }
+    constantD_ = dict.readIfPresent("D", D_);
 
     dict.readIfPresent("nCorr", nCorr_);
     dict.readIfPresent("resetOnStartUp", resetOnStartUp_);
@@ -256,11 +251,11 @@ bool Foam::functionObjects::scalarTransport::read(const dictionary& dict)
 
 bool Foam::functionObjects::scalarTransport::execute()
 {
-    Log << type() << " write:" << endl;
-
     volScalarField& s = transportedField();
 
-    const surfaceScalarField& phi = 
+    Log << type() << " execute: " << s.name() << endl;
+
+    const surfaceScalarField& phi =
         mesh_.lookupObject<surfaceScalarField>(phiName_);
 
     // Calculate the diffusivity
diff --git a/src/functionObjects/solvers/scalarTransport/scalarTransport.H b/src/functionObjects/solvers/scalarTransport/scalarTransport.H
index e2570fc7f9f805ce3b9a3e83f9d7785be928c946..bc743e7eea2601e965340214ae3a7ab71eb125c0 100644
--- a/src/functionObjects/solvers/scalarTransport/scalarTransport.H
+++ b/src/functionObjects/solvers/scalarTransport/scalarTransport.H
@@ -111,17 +111,18 @@ Usage
     \table
         Property     | Description             | Required    | Default value
         type         | Type name: scalarTransport | yes      |
-        phi          | Name of flux field      | yes          |
+        field        | Name of the scalar field | no         | s
+        phi          | Name of flux field      | no          | phi
         rho          | Name of density field   | no          | rho
-        phase        | Name of the phase name  | no          | none
+        phase        | Name of the phase       | no          | none
         nut          | Name of the turbulence viscosity | no | none
         D            | Diffusion coefficient   | no          | auto generated
         nCorr        | Number of correctors    | no          | 0
         resetOnStartUp | Reset scalar to zero on start-up | no | no
-        schemesField | Name of field to specify schemes | no | fieldName
+        schemesField | Name of field to specify schemes | no | field name
         fvOptions    | List of scalar sources  | no          |
-        bounded01    | Bounds scalar between 0-1 for multiphase | no |true
-        phasePhiCompressed |Compressed flux for VOF | no | alphaPhiUn
+        bounded01    | Bounds scalar between 0-1 for multiphase | no | true
+        phasePhiCompressed | Compressed flux for VOF | no | alphaPhiUn
     \endtable
 
 See also
@@ -156,10 +157,10 @@ class scalarTransport
 {
     // Private data
 
-        //- Name of field to process
+        //- Name of the transport field.
         word fieldName_;
 
-        //- Name of flux field
+        //- Name of flux field (optional)
         word phiName_;
 
         //- Name of density field (optional)
@@ -168,10 +169,10 @@ class scalarTransport
         //- Name of turbulent viscosity field (optional)
         word nutName_;
 
-        //- Name of phase field
+        //- Name of phase field (optional)
         word phaseName_;
 
-        //- Name of phase field compressed flux
+        //- Name of phase field compressed flux (optional)
         word phasePhiCompressedName_;
 
         //- Diffusion coefficient (optional)