Checking hours…Mon–Fri 7:30am–5pm · Sat 9am–12pm01302 279234Trade account
Worcester Bosch Lower Case Seal 87186884490

Worcester Bosch

Worcester Bosch Lower Case Seal 87186884490

Worcester Bosch 87186884490 lower case seal for Greenstar Compact boilers, supplied singly as a direct replacement casing seal.

At a glance

  • Part type: Gaskets, seals and O-rings
  • Also known as 1030851
  • This part is fitted to a gas appliance; installation must be carried out by a Gas Safe registered engineer.
Manufacturer part no.
87186884490
GC number
J04-366
Showing prices

£3.89

£3.24 ex. VAT · VAT at 20%

Available to order · 3 working days
Available to order · 3 working days
Not certain it's the right part? The technical team verifies fitment before dispatch — no charge, and it stops a second trip.Call the technical teamSend a technical question

Same-day dispatch

Ordered by 4pm Mon–Fri, 10:30am Sat.

30-day returns

Unused, in original packaging.

What it is

The Worcester Bosch 87186884490 is a lower case seal used on Greenstar Compact boilers. It sits at the lower casing joint and forms a watertight barrier that keeps condensate and system water contained within the appliance. The seal is a serviceable item, so it can be renewed on its own when the original has hardened, flattened or started to weep.

Signs this part needs replacing

  • Water or condensate weeping from the lower casing joint during or after a run cycle
  • Rust staining, scale trails or damp patches around the base of the casing
  • The seal feels hard, brittle or flattened when checked by hand
  • Boiler pressure dropping repeatedly with no obvious leak elsewhere on the system
  • Visible splits, compression set or deformation on the seal face at service

Before you order

  • Check the GC number and appliance serial plate to confirm the boiler is one of the 71 listed models before ordering
  • Cross-reference the alternative number 1030851 against the part you are removing
  • Inspect the mating faces while the casing is open and renew any other seals disturbed during the job
  • This part is fitted to a gas appliance; installation must be carried out by a Gas Safe registered engineer.

Not sure which part?

Search by part number, product name or brand — our technical team confirms fitment before anything is dispatched.