Worcester Bosch Seal Inner Case To Sump 87161067950

The Worcester Bosch inner case to sump seal (part 87161067950) is a moulded sealing component that sits between the inner casing and the sump on Worcester Bosch Greenstar gas boilers. Its job is to close the joint between the two surfaces so that flue gases and condensate stay where they belong, rather than escaping into the casing or dripping onto components below. It is a service item rather than a wear-and-tear accessory, so it is normally renewed whenever the sump or inner case is disturbed.

• Water or condensate weeping from the joint between the inner case and the sump
• A visible trail of staining, scale or corrosion running down from the sump area
• The seal feels hard, flattened or brittle, or shows cracks and splits when handled
• The seal has been compressed out of shape and no longer sits flush in its groove
• Combustion readings or flue gas analysis that suggest the inner case is not sealing correctly

• Check the GC number on the appliance data badge against the compatibility list, as the same boiler family uses different seals across variants
• Confirm the part number on the old seal or the parts diagram before ordering, and note the alternative number 1021027
• Consider whether a full gasket and seal kit is needed if other joints are being opened at the same time
• This part is fitted to a gas appliance; installation must be carried out by a Gas Safe registered engineer.