sumDirection function in surfaceFieldValue FO does not write down the values, just zeros

sunDirection function used on faceZone on orthogonalMesh samples phi in surfaceFieldValue FO. FaceZone is set of internal faces. It writes the field (vtk) with real flux values in individual cells. However, into the text file where it should write the sum, only zeros are entered.

I did alter the direction specification from ortho direction to see if it gets better, but no. The reported value is still zero.