Worcester Bosch Electrode Set 87181070500

The Worcester Bosch 87181070500 is a set of electrodes used in the ignition and flame monitoring circuit of Worcester Bosch gas boilers. The electrodes sit in the combustion path, where they provide the ignition spark and feed the flame signal back to the control board. This set is listed for the 25 SI and 28 SI RSF combi range and the related British Gas and WR325 appliances.

• The boiler fails to light, with no spark at the burner at the start of a demand.
• Repeated lockouts or ignition faults that clear only after a reset.
• Intermittent flame detection, causing the burner to drop out shortly after lighting.
• Visible damage to the electrode tips, cracked ceramic insulators or heavy sooting across the electrode assembly.
• Erratic starting that worsens over time rather than appearing suddenly.

• Check the GC number or serial plate on the appliance against the compatibility list before ordering, as several SI and RSF variants use different assemblies.
• Confirm whether the previous numbers listed below match the part currently fitted to the boiler.
• Inspect the burner door seal and any gaskets disturbed during access, and replace them if they are compressed or perished.
• This part is fitted to a gas appliance; installation must be carried out by a Gas Safe registered engineer.