Diverter Valve removed from boiler. Once the filling loop, water-to-water heat exchanger and bypass tube are removed this can be unscrewed from the boiler. It connects via pipes with o-rings again so these need replacing and ring recesses cleaning to ensure a secure fit. The diaphragm is contained within the housing on the right of the valve. The left plastic manifold can be removed if necessary however I kept it in place as the joint was secure.. 'Why fix it if it ain't broke'?!