UK trade guideBoiler Spares 5 min readUpdated 11 July 2026

How to Replace the Ignition Electrode on a ATAG i36 Combi (UK)

Step-by-step UK guide to replacing the spark / ionisation electrode on a ATAG i36 Combi. Part numbers, torques, commissioning.

ATAG

The part

Renew the ignition and flame-sense electrodes on ATAG i36 Combi when you get F27 / EA / L2 flame-detection faults after a clean burn.

Isolate safely

Both electrodes on ATAG i36 Combi 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 ATAG i36 Combi 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?
ATAG i36 Combi 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 ATAG i36 Combi. Below 4 µA at steady state means clean or replace.
Do I need to notify the manufacturer?
Only if the ATAG i36 Combi is in warranty — ATAG require log of any part swap for labour claims.
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