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

Set Store

Out of stock for delivery

Tesla Tesla / Tesla Expansion Vessel Service Valve

£15.68

ex. VAT £13.07 Each

Set Store

Out of stock for delivery

Zilmet Zilmet / Expansion Vessel 18L
( 68 )

Product code: 64278

Expansion Vessel 18L

£34.98

ex. VAT £29.15 Each

Product options Select from 3 options
Set Store

Out of stock for delivery

Zilmet Zilmet / Expansion Vessel 12L
( 68 )

Product code: 70204

Expansion Vessel 12L

£29.98

ex. VAT £24.98 Each

Product options Select from 3 options
Set Store

Out of stock for delivery

Zilmet Zilmet / Expansion Vessel 8L
( 21 )

Product code: 29704

Expansion Vessel 8L

£24.98

ex. VAT £20.82 Each

Product options Select from 3 options
Set Store

Out of stock for delivery

Expansion Vessel Control Kit
( 8 )

Product code: 49934

Expansion Vessel Control Kit

£53.88

ex. VAT £44.90 Each

Set Store

Out of stock for delivery

Zilmet Zilmet / Expansion Vessel 25L
( 68 )

Product code: 72473

Expansion Vessel 25L

£39.98

ex. VAT £33.32 Each

Product options Select from 3 options
Set Store

Out of stock for delivery

Expansion Vessel Bracket 5 to 24L
( 7 )

£25.98

ex. VAT £21.65 Each

Set Store

Out of stock for delivery

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

£44.98

ex. VAT £37.48 Each

Set Store

Out of stock for delivery