Vaillant expansion vessels are designed for use in eco MAX VUW condensing, eco TEC VU condensing, home condensing, Guernsey and Jersey only condensing, eco MAX VU condensing, eco TEC VUI condensing and VWL heat pump accessory appliances. The expansion vessel is a chamber designed to protect water heating systems from excess pressure. It is filled with air, which acts as a cushion against system pressure spikes.

Brand Name	Vaillant