PCB part number location?

On Baxi Duo-tec 33 GA the PCB label is on the top-right of the board, printed as an 720-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 Baxi Duo-tec 33 GA is in warranty — Baxi 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 Baxi Duo-tec 33 GA.

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

Photograph every plug and its position on the Baxi Duo-tec 33 GA PCB before unclipping — connector positions differ subtly across firmware revisions.

Refill the Baxi Duo-tec 33 GA 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 Baxi Duo-tec 33 GA the PCB label is on the top-right of the board, printed as an 720-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 Baxi Duo-tec 33 GA is in warranty — Baxi require log of any part swap for labour claims.

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