Worcester Bosch O-Ring 22mm x 3mm EPDM 87161162590

The Worcester Bosch 87161162590 is a 22mm x 3mm O-ring moulded in EPDM rubber. It is a sealing component used within the water-carrying sections of Worcester Bosch Greenstar appliances, where it sits in a machined groove or recess and compresses to form a watertight joint between mating parts. EPDM is chosen for its resistance to hot water and the additives found in sealed heating systems, so the ring holds its shape and sealing force across repeated heating cycles.

• A weep or drip from the joint the ring seals, often showing as a crusty white or rusty stain around the housing
• Water tracking down the appliance casing or pooling on the floor beneath the boiler after the system has run
• The ring feels hard, flattened or brittle when the joint is opened, rather than springy
• Cracking, nicks or a flattened cross-section visible on the ring once removed
• A joint that continues to seep after being re-tightened, indicating the seal has taken a permanent set

• Check the GC number and model on the appliance data badge against the compatibility list, as the same O-ring size is used across several Greenstar variants
• Confirm the part number on the existing component or the appliance's parts list before ordering, and note the alternative number 1030201
• Inspect the mating faces while the joint is open; a scored or corroded face will not seal reliably with a new ring alone
• This part is fitted to a gas appliance; installation must be carried out by a Gas Safe registered engineer.