Worcester Burner Gasket Wb6 87161105340

Worcester

The Worcester Expansion Vessel Gasket (Part No. 87161105340) is a genuine OEM (Original Equipment Manufacturer) flat fiber/rubber washer designed specifically for the expansion vessel connection in Worcester Bosch Greenstar boilers. This gasket sits between the expansion vessel flexible hose (or pipe) and the main hydraulic manifold. Its primary role is to ensure a high-pressure, watertight seal that can handle the constant influx and efflux of water as the system heats and cools.

Key Features and Specifications
High-Compression Material: Manufactured from specialized reinforced fiber or high-density elastomer to prevent "creeping" or flattening under the high torque required for a permanent seal.

Thermal Stability: Engineered to maintain its structural integrity despite the significant temperature fluctuations typical of a primary heating circuit.

Genuine Worcester Bosch Part: Guaranteed to match the exact internal and external diameters of the expansion vessel union, ensuring no restriction of water flow.

Pressure Resistance: Built to withstand system pressures of up to 3 bar, protecting against the most common cause of boiler "weeping" leaks.

Direct Replacement: A critical safety-maintenance part that should be replaced whenever the expansion vessel is disconnected for testing or replacement.

Boiler Compatibility
This gasket is a standard hardware component used across the majority of the Worcester Greenstar range where an internal expansion vessel is fitted:

Greenstar CDi (Classic & Highflow): 25CDi, 30CDi, 35CDi, 40CDi, 42CDi.

Greenstar i Junior: 24i Junior, 28i Junior.

Greenstar Si & Si Compact: 25Si, 29Si, 30Si.

Greenstar i (Combi & System): 24i, 25i, 30i.

Greenstar Ri: 12Ri, 15Ri, 18Ri, 24Ri.

Technical Tip: If your boiler pressure is rising rapidly when the heating is on and then dropping to zero when cold, your expansion vessel may need re-charging or replacing. When checking the vessel, always have a spare 87161105340 gasket on hand; the old gasket will almost certainly have hardened and will likely leak if reused.

Essential Companion Products
To ensure a complete and professional hydraulic service, the following genuine Worcester parts are frequently required alongside this gasket:

Hydraulic Control: Worcester Membrane – 87155058250

Air Management: Worcester Air Vent Gasket – 87161064450

Ignition Part: Worcester Electrode – 87161063560

Water Sealing: Worcester O-Ring – 87161138510

Hardware: Worcester Retaining Nut – 87161066830

Specialist Support and Local Collection
Are you experiencing pressure loss or noticed a leak at the back of your boiler near the expansion vessel? Our trade counter team can help you identify if you simply need a new gasket or if the expansion vessel itself has failed.

Visit our trade counter and Bathroom Showroom at 61 Fullers Road, E18 2QB for expert technical advice and immediate access to genuine Worcester Bosch spares.