Fit the highest point of the Baxi Duo-tec 33 GA circuit — that is where entrained air collects.

How often should I service?

Annually — the float sticks with sludge in unfiltered systems.

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.

Fit a new AAV on Baxi Duo-tec 33 GA when the boiler airlocks on start-up or the pump makes gurgling noises after refilling.

Isolate flow and return, unscrew the AAV from the top of the pump head or air separator on Baxi Duo-tec 33 GA.

Loosen the AAV cap one full turn once refitted — a fully-closed cap defeats the float.

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.

Any special height?: Fit the highest point of the Baxi Duo-tec 33 GA circuit — that is where entrained air collects.
How often should I service?: Annually — the float sticks with sludge in unfiltered systems.
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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