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.
Ariston Ariston / Ariston Andris Expansion Vessel & Non-Return Valve KIT A
20% Off
( 11 )

£43.82 was £54.78

ex. VAT £36.52 Each

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Zilmet Zilmet / Expansion Vessel 12L
( 68 )

Product code: 70204

Expansion Vessel 12L

£29.98

ex. VAT £24.98 Each

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Zilmet Zilmet / Expansion Vessel 18L
( 68 )

Product code: 64278

Expansion Vessel 18L

£34.98

ex. VAT £29.15 Each

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Expansion Vessel Control Kit
( 8 )

Product code: 49934

Expansion Vessel Control Kit

£53.88

ex. VAT £44.90 Each

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Tesla Tesla / Tesla Expansion Vessel Service Valve

£15.68

ex. VAT £13.07 Each

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Zilmet Zilmet / Expansion Vessel 8L
( 22 )

Product code: 29704

Expansion Vessel 8L

£24.98

ex. VAT £20.82 Each

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Expansion Vessel Bracket 5 to 24L
( 7 )

£25.98

ex. VAT £21.65 Each

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Tesla Tesla / T-BAR Expansion Vessel Fixing Bar Kit
( 3 )

£44.98

ex. VAT £37.48 Each

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Zilmet Zilmet / Expansion Vessel 25L
( 68 )

Product code: 72473

Expansion Vessel 25L

£39.98

ex. VAT £33.32 Each

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