diff --git a/src/thermophysicalModels/radiation/derivedFvPatchFields/MarshakRadiation/MarshakRadiationMixedFvPatchScalarField.C b/src/thermophysicalModels/radiation/derivedFvPatchFields/MarshakRadiation/MarshakRadiationMixedFvPatchScalarField.C
index 9ae7b435ca..9bc80d5c9f 100644
--- a/src/thermophysicalModels/radiation/derivedFvPatchFields/MarshakRadiation/MarshakRadiationMixedFvPatchScalarField.C
+++ b/src/thermophysicalModels/radiation/derivedFvPatchFields/MarshakRadiation/MarshakRadiationMixedFvPatchScalarField.C
@@ -77,24 +77,19 @@ Foam::MarshakRadiationFvPatchScalarField::MarshakRadiationFvPatchScalarField
 {
     if (dict.found("value"))
     {
-        fvPatchScalarField::operator=
-        (
-            scalarField("value", dict, p.size())
-        );
-        refValue() = scalarField("refValue", dict, p.size());
-        refGrad() = scalarField("refGradient", dict, p.size());
-        valueFraction() = scalarField("valueFraction", dict, p.size());
+        refValue() = scalarField("value", dict, p.size());
     }
     else
     {
-        const scalarField& Tp =
-            patch().lookupPatchField<volScalarField, scalar>(TName_);
-
-        refValue() = 4.0*constant::physicoChemical::sigma.value()*pow4(Tp);
-        refGrad() = 0.0;
-
-        fvPatchScalarField::operator=(refValue());
+        refValue() = 0.0;
     }
+
+    // zero gradient
+    refGrad() = 0.0;
+
+    valueFraction() = 1.0;
+
+    fvPatchScalarField::operator=(refValue());
 }
 
 
diff --git a/src/thermophysicalModels/radiation/derivedFvPatchFields/MarshakRadiationFixedT/MarshakRadiationFixedTMixedFvPatchScalarField.C b/src/thermophysicalModels/radiation/derivedFvPatchFields/MarshakRadiationFixedT/MarshakRadiationFixedTMixedFvPatchScalarField.C
index 99b5c68267..cb8cc7db97 100644
--- a/src/thermophysicalModels/radiation/derivedFvPatchFields/MarshakRadiationFixedT/MarshakRadiationFixedTMixedFvPatchScalarField.C
+++ b/src/thermophysicalModels/radiation/derivedFvPatchFields/MarshakRadiationFixedT/MarshakRadiationFixedTMixedFvPatchScalarField.C
@@ -78,24 +78,15 @@ MarshakRadiationFixedTMixedFvPatchScalarField
     Trad_("Trad", dict, p.size()),
     emissivity_(readScalar(dict.lookup("emissivity")))
 {
-    if (dict.found("value"))
-    {
-        fvPatchScalarField::operator=
-        (
-            scalarField("value", dict, p.size())
-        );
-        refValue() = scalarField("refValue", dict, p.size());
-        refGrad() = scalarField("refGradient", dict, p.size());
-        valueFraction() = scalarField("valueFraction", dict, p.size());
-    }
-    else
-    {
-        refValue() = 4.0*constant::physicoChemical::sigma.value()*pow4(Trad_);
-        refGrad() = 0.0;
-        valueFraction() = 1.0;
+    // refValue updated on each call to updateCoeffs()
+    refValue() = 4.0*constant::physicoChemical::sigma.value()*pow4(Trad_);
 
-        fvPatchScalarField::operator=(refValue());
-    }
+    // zero gradient
+    refGrad() = 0.0;
+
+    valueFraction() = 1.0;
+
+    fvPatchScalarField::operator=(refValue());
 }