Can I clean rather than replace?

Yes for a limescaled unit — soak the turbine in citric acid, but replace if the Hall-effect PCB is corroded.

What minimum flow triggers?

The Vaillant ecoTEC Plus 424 typically ignites at 2.5 L/min. Below that, check the aerator on the DHW outlet.

Only if the Vaillant ecoTEC Plus 424 is in warranty — Vaillant require log of any part swap for labour claims.

Swap the DHW turbine on Vaillant ecoTEC Plus 424 when hot water runs cold at low flow or the boiler fails to fire on demand.

Isolate cold mains at the boiler's blue isolator. The sensor on Vaillant ecoTEC Plus 424 clips into the hydraulic block with two retaining clips.

Fit new O-rings and align the turbine so the flow arrow matches the cold mains direction.

Refill the Vaillant ecoTEC Plus 424 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.

Can I clean rather than replace?: Yes for a limescaled unit — soak the turbine in citric acid, but replace if the Hall-effect PCB is corroded.
What minimum flow triggers?: The Vaillant ecoTEC Plus 424 typically ignites at 2.5 L/min. Below that, check the aerator on the DHW outlet.
Do I need to notify the manufacturer?: Only if the Vaillant ecoTEC Plus 424 is in warranty — Vaillant require log of any part swap for labour claims.

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