diff --git a/src/functionObjects/field/wallHeatFlux/wallHeatFlux.C b/src/functionObjects/field/wallHeatFlux/wallHeatFlux.C
index e4984c478a..59bee35c32 100644
--- a/src/functionObjects/field/wallHeatFlux/wallHeatFlux.C
+++ b/src/functionObjects/field/wallHeatFlux/wallHeatFlux.C
@@ -85,7 +85,7 @@ void Foam::functionObjects::wallHeatFlux::calcHeatFlux
 
         forAll(wallHeatFluxBf, patchi)
         {
-            wallHeatFluxBf[patchi] += radHeatFluxBf[patchi];
+            wallHeatFluxBf[patchi] -= radHeatFluxBf[patchi];
         }
     }
 }