Vaillant Valve 3 Way 0020020015Vaillant Valve 3 Way 0020020015 This component manages water flow between heating and domestic hot water circuits with minimal pressure loss, ensuring stable system operation. By seamlessly switching between heating and hot water modes, it enables your combi boiler to deliver both services efficiently from a single compact unit. Genuine Vaillant component built to exacting specifications for reliable performance and system longevity. Vaillant 3 way