Warranty implications?

A HEX swap on an in-warranty Baxi Duo-tec 40 GA must be logged with the manufacturer — otherwise the labour claim voids.

Mandatory — power-flush and fit a magnetic filter or the new HEX will block within two years.

Do I need to notify the manufacturer?

Only if the Baxi Duo-tec 40 GA is in warranty — Baxi require log of any part swap for labour claims.

Replace the primary heat exchanger on Baxi Duo-tec 40 GA when you see combustion products blowing back, F62/L9 faults or sooting on the burner.

Drain and cap all four connections on Baxi Duo-tec 40 GA. The HEX weighs 12–18 kg — get a second pair of hands.

Torque new HEX unions to the OEM figure (typically 40 Nm for cast, 28 Nm for stainless) and refit new burner and door gaskets.

Refill the Baxi Duo-tec 40 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.

Warranty implications?: A HEX swap on an in-warranty Baxi Duo-tec 40 GA must be logged with the manufacturer — otherwise the labour claim voids.
System clean first?: Mandatory — power-flush and fit a magnetic filter or the new HEX will block within two years.
Do I need to notify the manufacturer?: Only if the Baxi Duo-tec 40 GA is in warranty — Baxi require log of any part swap for labour claims.

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