It may be tempting to opt for a low cost spare part, but do consider the impact that this may have. Counterfeit parts are typically substandard, manufactured from poor quality materials thus impacting on the design and strength of the product. In the event of a system failure or - in a worst case scenario, an accident - the ultimate responsibility lies with the service and repair engineer rather than the product which was ill-chosen for the application. It is always reccommended you go for an official part, such as this one.
For use with Vaillant intelligent eBUS controls on single or two zone heating systems with open vent or system boiler and cylinder
Connections for one 3-port or two 2-port valves for single zone