Valve positioners for all manifolds currently on the market are subject to mechanical wear. Use the valve replacement kit to get your digital manifold from Testo working again really quickly. Replacing the valve positioners is very easy and can be carried out independently on site. With the valve replacement kit, you can replace two valve positioners - on the high pressure and low pressure side, or at the two middle connections on the digital manifold. Please order another kit if you would like to replace all 4 valve positioners.