Worcester Bosch O-Ring 12 x 3mm Pack 10 87102050890

This is a Worcester Bosch O-ring, sized 12 x 3mm and supplied in a pack of 10. It is a sealing component used at joints and connections inside Greenstar combi and condensing appliances, where it prevents water or gas from escaping past a mating surface. O-rings of this type sit in a groove and compress when the joint is tightened, so the seal depends on the ring being soft, round and free from damage.

• A weep or trace of water around a joint, pump connection or manifold face
• The ring has flattened, hardened or taken a set instead of returning to shape
• Visible cracking, nicks or cuts across the ring section
• Scale or corrosion debris sitting in the seal groove
• A joint that continues to seep after being re-tightened

• Check the GC number or serial plate on the appliance to confirm this O-ring suits your model.
• Cross-check the alternative number 1012375 against any documentation you hold for the boiler.
• If the joint is being opened for another repair, confirm whether a full gasket and seal kit is needed alongside this ring.
• This part is fitted to a gas appliance; installation must be carried out by a Gas Safe registered engineer.