Worcester Bosch Heat Exchanger Basic Block C/W Sump 8716119315

The heat exchanger basic block with sump is a Worcester Bosch component that transfers heat from the combustion circuit into the domestic water and heating system. It sits at the core of the appliance and is supplied as a complete block assembly with the sump fitted. This part is used across the Worcester British Gas Greenstar i-series range, including combi and system variants in both natural gas and LPG formats.

• Water or staining around the heat exchanger body or sump area, indicating a breach in the casing or seals
• Repeated loss of system pressure that cannot be traced to the usual external causes
• Overheating, kettling or banging noises during the heating cycle
• Reduced hot water or heating output despite the burner running normally
• Visible corrosion, scale build-up or distortion on the block or sump faces

• Check the GC number and appliance serial plate against the compatibility list to confirm the correct variant for your boiler
• Cross-reference the previous numbers listed above, as earlier versions of this block may be fitted to older appliances
• Inspect the sealing faces and confirm whether replacement gaskets or seals are needed alongside the block
• This part is fitted to a gas appliance; installation must be carried out by a Gas Safe registered engineer.