PCB part number location?

On ATAG i36 Combi the PCB label is on the top-right of the board, printed as an S43-series code. Match every digit.

Do I need to re-parameterise?

Yes — enter the correct boiler model code in the service menu after fitting so the ignition curve, fan speed and gas rate match.

Only if the ATAG i36 Combi is in warranty — ATAG require log of any part swap for labour claims.

Replace the main control PCB — the most common cause of no-heat, no-DHW and intermittent lockouts on ATAG i36 Combi.

Isolate at the fused spur and lock off. Discharge any residual mains voltage before touching connectors.

Photograph every plug and its position on the ATAG i36 Combi PCB before unclipping — connector positions differ subtly across firmware revisions.

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.

PCB part number location?: On ATAG i36 Combi the PCB label is on the top-right of the board, printed as an S43-series code. Match every digit.
Do I need to re-parameterise?: Yes — enter the correct boiler model code in the service menu after fitting so the ignition curve, fan speed and gas rate match.
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.

Shop the spares

Browse boiler spares — 14,820 live parts.