Worcester Bosch O-Ring 3.0mm x 21.5mm 87161408260

A Worcester Bosch O-ring with a 3.0mm cross section and a 21.5mm internal diameter, supplied under part number 87161408260. It is a sealing component used where pipes and internal assemblies meet other parts of the boiler, and it forms part of the wider range of Worcester O-rings, gaskets and washers that keep water and gas paths tight. Seals of this type are found on heat exchangers, fans and connecting pipework, where they prevent leakage at the joint face.

• Water weeping or a damp trace around a pipe-to-component joint that reappears after tightening
• The O-ring has hardened, flattened or cracked, so it no longer springs back when the joint is disturbed
• Scale or corrosion debris sitting in the seal groove, preventing the ring from seating properly
• A joint that has been opened for another repair and needs a fresh seal on reassembly
• Repeated pressure loss or a visible drip at the affected connection during a service visit

• Confirm the GC number and boiler model against the compatibility list, as the same appliance family uses several different seal sizes
• Check the existing O-ring dimensions before fitting, since section and internal diameter must match the groove it sits in
• Note the alternative and previous part numbers 1017573 and ZMMIS172 when cross-referencing older documentation
• Assess whether the surrounding gaskets and washers on the same joint also need renewing while access is available