Worcester Bosch Expansion Vessel 87161076600

The Worcester Bosch 87161076600 is an expansion vessel for the Greenstar Heatslave range of oil-fired condensing boilers. It sits within the heating circuit and takes up the extra volume created as the system water heats and expands, keeping pressure stable and protecting parts such as the pressure relief valve from repeated discharge. Worcester Bosch specifies this vessel for the Heatslave HE and Heatslave II internal models.

• System pressure climbs quickly once the boiler fires and the water heats up
• Pressure relief valve discharges water, often leaving a trail from the discharge pipe
• Boiler pressure gauge reads high when hot and falls back when cold
• Frequent top-ups needed to hold the correct cold fill pressure
• Water weeping from the vessel connection, or the vessel feels heavy when removed

• Confirm the appliance model and serial number against the compatibility list
• Match the part number on the existing vessel to 87161076600 before ordering
• Check whether the vessel connection needs a new seal or washer at the same time