UK trade guideBoiler Spares 5 min readUpdated 11 July 2026

How to Replace the Pcb on a Baxi EcoBlue Advance 28 (UK)

Step-by-step UK guide to replacing the printed circuit board on a Baxi EcoBlue Advance 28. Part numbers, torques, commissioning.

Baxi

The part

Replace the main control PCB — the most common cause of no-heat, no-DHW and intermittent lockouts on Baxi EcoBlue Advance 28.

Isolate safely

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

Fit and commission

Photograph every plug and its position on the Baxi EcoBlue Advance 28 PCB before unclipping — connector positions differ subtly across firmware revisions.

Recommission checklist

Refill the Baxi EcoBlue Advance 28 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

PCB part number location?
On Baxi EcoBlue Advance 28 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 EcoBlue Advance 28 is in warranty — Baxi require log of any part swap for labour claims.
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