diff --git a/dumux/boxmodels/2pni/2pnifluxvariables.hh b/dumux/boxmodels/2pni/2pnifluxvariables.hh
index 420d0bcaa2622c5f703027e5f5da5c83856de648..5f1450649abdeaaa75d0c2b17ab43f305652586d 100644
--- a/dumux/boxmodels/2pni/2pnifluxvariables.hh
+++ b/dumux/boxmodels/2pni/2pnifluxvariables.hh
@@ -70,6 +70,17 @@ class TwoPNIFluxVariables : public TwoPFluxVariables<TypeTag>
     typedef Dune::FieldVector<CoordScalar, dimWorld> Vector;
 
 public:
+
+    /*
+        * \brief The constructor
+        *
+        * \param problem The problem
+        * \param element The finite element
+        * \param elemGeom The finite-volume geometry in the box scheme
+        * \param faceIdx The local index of the SCV (sub-control-volume) face
+        * \param elemDat The volume variables of the current element
+        */
+
     TwoPNIFluxVariables(const Problem &problem,
                    const Element &element,
                    const FVElementGeometry &elemGeom,
diff --git a/dumux/boxmodels/2pni/2pniindices.hh b/dumux/boxmodels/2pni/2pniindices.hh
index 5cdcdbc5990763943b9e5ca1f594597d7a17f16f..7e84fcd99ad7828d6c3d6e2c779ad372f4711e0a 100644
--- a/dumux/boxmodels/2pni/2pniindices.hh
+++ b/dumux/boxmodels/2pni/2pniindices.hh
@@ -39,6 +39,9 @@ class TwoPNIIndices : public TwoPIndices<PVOffset>
 public:
     static const int temperatureIdx = PVOffset + 2; //! The primary variable index for temperature
     static const int energyEqIdx = PVOffset + 2; //! The equation index of the energy equation
+    // Phase indices
+       static const int wPhaseIdx = 0; //!< Index of the wetting phase in a phase vector
+       static const int nPhaseIdx = 1; //!< Index of the non-wetting phase in a phase vector
 };
 // \}
 }
diff --git a/dumux/boxmodels/2pni/2pnilocalresidual.hh b/dumux/boxmodels/2pni/2pnilocalresidual.hh
index 77403f62e3ff0c63aa54687b929c97591db32be8..1ae7b921f34e278d7723bd4baf62c73152b09247 100644
--- a/dumux/boxmodels/2pni/2pnilocalresidual.hh
+++ b/dumux/boxmodels/2pni/2pnilocalresidual.hh
@@ -81,10 +81,14 @@ class TwoPNILocalResidual : public TwoPLocalResidual<TypeTag>
 public:
     /*!
      * \brief Evaluate the amount all conservation quantites
-     *        (e.g. phase mass) within a sub-control volume.
+     *        (e.g. phase mass and energy storage) within a sub-control volume.
      *
      * The result should be averaged over the volume (e.g. phase mass
      * inside a sub control volume divided by the volume)
+     *
+     *  \param result The phase mass within the sub-control volume
+     *  \param scvIdx The SCV (sub-control-volume) index
+     *  \param usePrevSol Evaluate function with solution of current or previous time step
      */
     void computeStorage(PrimaryVariables &result, int scvIdx, bool usePrevSol) const
     {
@@ -116,6 +120,10 @@ public:
      * over a face of a subcontrol volume and writes the result in
      * the flux vector.
      *
+     * \param flux The advective flux over the sub-control-volume face for each phase
+     * \param fluxVars The flux variables at the current SCV
+     *
+     *
      * This method is called by compute flux (base class)
      */
     void computeAdvectiveFlux(PrimaryVariables &flux,
@@ -158,6 +166,10 @@ public:
     /*!
      * \brief Adds the diffusive heat flux to the flux vector over
      *        the face of a sub-control volume.
+     *
+     * \param flux The diffusive flux over the sub-control-volume face for each phase
+     * \param fluxData The flux variables at the current SCV
+     *
      */
     void computeDiffusiveFlux(PrimaryVariables &flux,
                               const FluxVariables &fluxData) const
diff --git a/dumux/boxmodels/2pni/2pniproblem.hh b/dumux/boxmodels/2pni/2pniproblem.hh
index 1d791661a9fb966576bf3ca5ae5a831ddb16019c..10847cd52698dcc394c65c7c88f927567c0853b4 100644
--- a/dumux/boxmodels/2pni/2pniproblem.hh
+++ b/dumux/boxmodels/2pni/2pniproblem.hh
@@ -44,6 +44,12 @@ class TwoPNIProblem : public TwoPProblem<TypeTag>
     typedef typename GET_PROP_TYPE(TypeTag, PTAG(TimeManager)) TimeManager;
 
 public:
+    /*!
+     * \brief The constructor
+     *
+     * \param timeManager The time manager
+     * \param gridView The grid view
+        */
     TwoPNIProblem(TimeManager &timeManager, const GridView &gridView)
         : ParentType(timeManager, gridView)
     {}
diff --git a/dumux/boxmodels/2pni/2pnipropertydefaults.hh b/dumux/boxmodels/2pni/2pnipropertydefaults.hh
index 4812134d651e92bfeb146b3d6e254d137b45b69c..f70e191cd088e29e5098cd5a558d9d841f52b00e 100644
--- a/dumux/boxmodels/2pni/2pnipropertydefaults.hh
+++ b/dumux/boxmodels/2pni/2pnipropertydefaults.hh
@@ -35,6 +35,10 @@
 
 namespace Dumux
 {
+/*!
+ * \addtogroup TwoPNIBoxModel
+ */
+
 namespace Properties
 {
 //////////////////////////////////////////////////////////////////
diff --git a/dumux/boxmodels/2pni/2pnivolumevariables.hh b/dumux/boxmodels/2pni/2pnivolumevariables.hh
index c55d60c357b0d8f22287ab60c3e4197b4a1f2822..51349cd473fd3acd012d21ff396d73075c71fe98 100644
--- a/dumux/boxmodels/2pni/2pnivolumevariables.hh
+++ b/dumux/boxmodels/2pni/2pnivolumevariables.hh
@@ -48,7 +48,8 @@ class TwoPNIVolumeVariables : public TwoPVolumeVariables<TypeTag>
         dim = GridView::dimension,
         dimWorld = GridView::dimensionworld,
 
-        numPhases = GET_PROP_VALUE(TypeTag, PTAG(NumPhases))
+        numPhases = GET_PROP_VALUE(TypeTag, PTAG(NumPhases)),
+
     };
 
     typedef typename GET_PROP_TYPE(TypeTag, PTAG(TwoPIndices)) Indices;
@@ -65,6 +66,13 @@ class TwoPNIVolumeVariables : public TwoPVolumeVariables<TypeTag>
 public:
     /*!
      * \brief Update all quantities for a given control volume.
+     * \param priVars The local primary variable vector
+     * \param problem The problem object
+     * \param element The current element
+     * \param elemGeom The finite-volume geometry in the box scheme
+     * \param scvIdx The local index of the SCV (sub-control volume)
+     * \param isOldSol Evaluate function with solution of current or previous time step
+     *
      */
     void update(const PrimaryVariables &priVars,
                 const Problem &problem,
@@ -100,6 +108,17 @@ public:
         Valgrind::CheckDefined(enthalpy_);
     }
 
+    /*!
+        * \brief Update the temperature for a given control volume.
+        *
+        * \param priVars The local primary variable vector
+        * \param element The current element
+        * \param elemGeom The finite-volume geometry in the box scheme
+        * \param scvIdx The local index of the SCV (sub-control volume)
+        * \param problem The problem object
+        *
+        */
+
     // this method gets called by the parent class
     void updateTemperature_(const PrimaryVariables &priVars,
                             const Element &element,
@@ -120,6 +139,9 @@ public:
     /*!
      * \brief Returns the total internal energy of a phase in the
      *        sub-control volume.
+     *
+     * \param phaseIdx The phase index
+     *
      */
     Scalar internalEnergy(int phaseIdx) const
     { return internalEnergy_[phaseIdx]; };
@@ -127,6 +149,8 @@ public:
     /*!
      * \brief Returns the total enthalpy of a phase in the sub-control
      *        volume.
+     *
+     *  \param phaseIdx The phase index
      */
     Scalar enthalpy(int phaseIdx) const
     { return enthalpy_[phaseIdx]; };