diff --git a/applications/solvers/incompressible/pimpleFoam/overPimpleDyMFoam/pEqn.H b/applications/solvers/incompressible/pimpleFoam/overPimpleDyMFoam/pEqn.H
index 9baea7b716f0fa0dc11ce59558cdc55423673116..e6acdd5b04289da6eefcc0fd978e46478d6cb636 100644
--- a/applications/solvers/incompressible/pimpleFoam/overPimpleDyMFoam/pEqn.H
+++ b/applications/solvers/incompressible/pimpleFoam/overPimpleDyMFoam/pEqn.H
@@ -20,7 +20,7 @@ surfaceScalarField faceMask(localMin<scalar>(mesh).interpolate(cellMask));
 surfaceScalarField rAUf("rAUf", faceMask*fvc::interpolate(rAU));
 
 volVectorField HbyA("HbyA", U);
-HbyA = constrainHbyA(rAU*UEqn.H(), U, p);
+HbyA = constrainHbyA(cellMask*rAU*UEqn.H(), U, p);
 
 //mesh.interpolate(HbyA);
 if (massFluxInterpolation)