This Expansion vessel, suitable for a range of Vaillant Boilers including the Ecotec Pro 2006-2010 & Ecotec Plus 2005 -2010, is used to protect closed water heating systems from pressure build up within the system. Filled with air, the expansion vessel acts as a cushion against those surges in pressure. This spare part is suitable for a range of Baxi Boilers, including the Baxi Solo HE, Duotec HE, Main Eco, Potterton Gold, Heatmax, Promax Combi & Promax HE Store

• Can not be used for drinking water
• Fits a large number of Baxi, main and potterton boilers