How to Replace the Ignition Electrode on a Worcester Bosch Greenstar Danesmoor 12/18 (UK)
Step-by-step UK guide to replacing the spark / ionisation electrode on a Worcester Bosch Greenstar Danesmoor 12/18. Part numbers, torques, commissioning.
The part
Renew the ignition and flame-sense electrodes on Worcester Bosch Greenstar Danesmoor 12/18 when you get F27 / EA / L2 flame-detection faults after a clean burn.
Isolate safely
Both electrodes on Worcester Bosch Greenstar Danesmoor 12/18 use ceramic insulators — never re-use if chipped.
Fit and commission
Set the spark gap to 3.5–4.0 mm and the ionisation gap so the tip sits 4–5 mm above the burner surface.
Recommission checklist
Refill the Worcester Bosch Greenstar Danesmoor 12/18 to 1.2 bar cold. Bleed high-point radiators and the internal AAV.
Run a full flue-gas analysis after 15 minutes. Log the reading against the OEM commissioning envelope in the Benchmark book.
Frequently asked questions
- Combined or separate?
- Worcester Bosch Greenstar Danesmoor 12/18 runs a two-electrode kit — one spark, one sense. Fit both together to avoid a second call-back.
- How do I test ionisation current?
- In service mode read the µA value on Worcester Bosch Greenstar Danesmoor 12/18. Below 4 µA at steady state means clean or replace.
- Do I need to notify the manufacturer?
- Only if the Worcester Bosch Greenstar Danesmoor 12/18 is in warranty — Worcester Bosch require log of any part swap for labour claims.
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