UK trade guideBoiler Spares 5 min readUpdated 11 July 2026

How to Replace the Fan on a Baxi Platinum Combi 40 (UK)

Step-by-step UK guide to replacing the combustion fan on a Baxi Platinum Combi 40. Part numbers, torques, commissioning.

Baxi

The part

Swap the combustion fan on Baxi Platinum Combi 40 when you get low-speed lockouts (F28/F29 Vaillant, EA Worcester, F1 Ideal) or bearing whine.

Isolate safely

Remove the case, disconnect the fan plug and Venturi. Note the fan's part number stamped on the motor housing.

Fit and commission

On Baxi Platinum Combi 40 the fan is torqued to 8–10 Nm — over-tightening cracks the composite plenum.

Recommission checklist

Refill the Baxi Platinum Combi 40 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

Which speed sensor connector?
The Hall-effect sensor on Baxi Platinum Combi 40 uses a 4-pin JST plug. Do not swap L1/L2.
Do I need a new gasket?
Always fit the OEM Viton gasket — the old one hardens and leaks flue gases into the case.
Do I need to notify the manufacturer?
Only if the Baxi Platinum Combi 40 is in warranty — Baxi require log of any part swap for labour claims.
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