diff --git a/src/finiteVolume/fvMatrices/fvMatrix/fvMatrix.C b/src/finiteVolume/fvMatrices/fvMatrix/fvMatrix.C
index 091f0cf084..ecc7350a84 100644
--- a/src/finiteVolume/fvMatrices/fvMatrix/fvMatrix.C
+++ b/src/finiteVolume/fvMatrices/fvMatrix/fvMatrix.C
@@ -927,6 +927,7 @@ void Foam::fvMatrix<Type>::operator=(const fvMatrix<Type>& fvmv)
             << abort(FatalError);
     }
 
+    dimensions_ = fvmv.dimensions_;
     lduMatrix::operator=(fvmv);
     source_ = fvmv.source_;
     internalCoeffs_ = fvmv.internalCoeffs_;