Why does the new one still weep?

Almost always the expansion vessel — check pre-charge first before condemning the PRV.

Only fit WRAS-approved 3-bar PRVs to keep Baxi Duo-tec 40 GA within its Gas Safe commissioning envelope.

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.

Fit a new 3-bar PRV on Baxi Duo-tec 40 GA when water dribbles constantly from the outside discharge pipe.

Drain below the PRV, unscrew the old valve and fit new PTFE tape (10 turns clockwise).

On Baxi Duo-tec 40 GA the PRV sits on the hydraulic block — torque to 25 Nm to avoid cracking the plastic manifold.

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.

Why does the new one still weep?: Almost always the expansion vessel — check pre-charge first before condemning the PRV.
Any WRAS approval?: Only fit WRAS-approved 3-bar PRVs to keep Baxi Duo-tec 40 GA within its Gas Safe commissioning envelope.
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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