Expansion Vessels

Shop high-quality boiler expansion vessels from trusted brands at Toolstation. Find products in various sizes and configurations, from 5L potable expansion vessels to 25L external expansion vessels.

What Are Boiler Expansion Vessels Used For?

A boiler expansion tank is an essential component of any central heating system, helping to regulate pressure. They are found in most domestic boiler systems and all combi boilers.

Expansion vessels contain air and water to counteract changes in pressure as water is heated and cooled, keeping your boiler safe and working efficiently. Like overflow tanks, they allow excess nitrogen and water to escape from the central heating system.