diff --git a/applications/solvers/multiphase/multiphaseEulerFoam/multiphaseEulerFoam/YEqns.H b/applications/solvers/multiphase/multiphaseEulerFoam/multiphaseEulerFoam/YEqns.H
index b3ea61bee1..23a633e573 100644
--- a/applications/solvers/multiphase/multiphaseEulerFoam/multiphaseEulerFoam/YEqns.H
+++ b/applications/solvers/multiphase/multiphaseEulerFoam/multiphaseEulerFoam/YEqns.H
@@ -26,7 +26,9 @@
             );
 
             YiEqn.relax();
+            fvConstraints.constrain(YiEqn);
             YiEqn.solve("Yi");
+            fvConstraints.constrain(Y[i]);
         }
     }