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.
Zilmet
( 70 )

Product code: 64278

Expansion Vessel 18L

£38.71

ex. VAT £32.26 Each

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Out of stock for delivery

Ariston
( 12 )

£54.78

ex. VAT £45.65 Each

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20+ available for delivery

Zilmet
( 70 )

Product code: 70204

Expansion Vessel 12L

£33.19

ex. VAT £27.66 Each

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Out of stock for delivery

Zilmet
( 24 )

Product code: 29704

Expansion Vessel 8L

£27.66

ex. VAT £23.05 Each

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Out of stock for delivery

( 9 )

Product code: 49934

Expansion Vessel Control Kit

£56.89

ex. VAT £47.41 Each

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1 available for delivery

( 7 )

£30.67

ex. VAT £25.56 Each

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8 available for delivery

Tesla

£15.68

ex. VAT £13.07 Each

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7 available for delivery

Zilmet
( 70 )

Product code: 72473

Expansion Vessel 25L

£44.26

ex. VAT £36.88 Each

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Out of stock for delivery

Tesla
( 3 )

£44.98

ex. VAT £37.48 Each

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Out of stock for delivery