diff --git a/src/functionObjects/field/wallHeatFlux/wallHeatFlux.C b/src/functionObjects/field/wallHeatFlux/wallHeatFlux.C
index 584c6d366..7cce82e6a 100644
--- a/src/functionObjects/field/wallHeatFlux/wallHeatFlux.C
+++ b/src/functionObjects/field/wallHeatFlux/wallHeatFlux.C
@@ -90,7 +90,7 @@ void Foam::functionObjects::wallHeatFlux::calcHeatFlux
 
         forAll(wallHeatFluxBf, patchi)
         {
-            wallHeatFluxBf[patchi] += radHeatFluxBf[patchi];
+            wallHeatFluxBf[patchi] -= radHeatFluxBf[patchi];
         }
     }
 }