Worcester Bosch Expansion Vessel 10 Litre 87154072460

The Worcester Bosch 87154072460 is a 10 litre expansion vessel used across a number of Greenstar and ICS1 appliances. It is a sealed tank divided internally so that a charge of air sits against the system water, absorbing the volume change as the heating circuit warms up and cools down. Without that cushion, the pressure rise in a sealed system would be passed straight to the boiler's safety devices and pipework.

• System pressure climbs quickly when the boiler heats up and drops again as it cools, with the gauge swinging more than it should.
• The pressure relief valve discharges during normal running, or water is found from the discharge pipe.
• The vessel feels heavy or water is heard inside it when the Schrader valve is depressed, indicating a failed internal diaphragm.
• The air charge will not hold, so the vessel needs recharging repeatedly.
• The boiler locks out or shows a low pressure fault shortly after topping up.

• Check the GC number or serial plate on the appliance against the compatibility list, as the same appliance family can use more than one vessel size.
• Confirm the part number 87154072460 or the alternative number 1013099 matches the vessel currently fitted.
• Have a suitable sealing washer or connection gasket to hand if the existing one is disturbed during removal.
• This part is fitted to a gas appliance; installation must be carried out by a Gas Safe registered engineer.