diff --git a/src/regionModels/surfaceFilmModels/thermoSingleLayer/thermoSingleLayer.C b/src/regionModels/surfaceFilmModels/thermoSingleLayer/thermoSingleLayer.C
index d15f78aff..2adad9eaf 100644
--- a/src/regionModels/surfaceFilmModels/thermoSingleLayer/thermoSingleLayer.C
+++ b/src/regionModels/surfaceFilmModels/thermoSingleLayer/thermoSingleLayer.C
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
-    \\  /    A nd           | Copyright (C) 2011-2016 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2017 OpenFOAM Foundation
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
 License
@@ -262,15 +262,17 @@ void thermoSingleLayer::updateSubmodels()
 
 tmp<fvScalarMatrix> thermoSingleLayer::q(volScalarField& hs) const
 {
+    const volScalarField alpha(pos(delta_ - deltaSmall_));
+
     return
     (
         // Heat-transfer to the primary region
       - fvm::Sp(htcs_->h()/Cp_, hs)
-      + htcs_->h()*(hs/Cp_ + alpha_*(TPrimary_ - T_))
+      + htcs_->h()*(hs/Cp_ + alpha*(TPrimary_ - T_))
 
         // Heat-transfer to the wall
       - fvm::Sp(htcw_->h()/Cp_, hs)
-      + htcw_->h()*(hs/Cp_ + alpha_*(Tw_- T_))
+      + htcw_->h()*(hs/Cp_ + alpha*(Tw_- T_))
     );
 }