Worcester Bosch Electrode Set Greenstar RSF 87181070640

The Worcester Bosch electrode set, part number 87181070640, is a replacement ignition and flame sensing assembly for Worcester Bosch Greenstar RSF natural gas boilers. The electrodes are mounted so that their tips sit within the combustion chamber, where they generate the spark that lights the burner and monitor whether a flame has established. The sensing side of the set feeds a signal back to the boiler control board, which uses it to decide whether the gas valve should stay open. Because the electrodes operate in the hottest part of the appliance, they are a recognised service item and are replaced when ignition becomes unreliable or the boiler begins to lock out.

• The boiler fails to ignite and goes to lockout, often with an ignition or flame detection fault shown on the display.
• Repeated ignition attempts with no spark, or a spark that is weak and intermittent.
• The burner lights and then extinguishes shortly afterwards, pointing to a flame sensing electrode that is not reading correctly.
• Visible damage to the electrode tips, cracked or discoloured ceramic insulators, or heavy carbon build-up across the assembly.
• The appliance runs but cuts out intermittently during a demand for heating or hot water.

• Confirm the boiler model and serial number against the compatibility list before ordering.
• Compare the existing electrode set against the alternative part number 1020133 to confirm the match.
• Inspect the gasket or seal at the electrode mounting point and renew it if it is perished or hardened.
• This part is fitted to a gas appliance; installation must be carried out by a Gas Safe registered engineer.