Baxi DHW Flow Detection / Diverter Valve Fault

Boiler does not fire for hot water unless heating is also on (combi boiler)

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

Possible Causes

Faulty Baxi DHW flow switch or turbine, Sticking diverter valve, Blocked inlet filter reducing flow, Microswitch failure on diverter assembly

Safety first: Hot water pipework can be very hot.

User checks:

Open a hot tap fully and check if the boiler indicates a DHW demand (tap symbol on display, if fitted).
Clean tap aerators and shower heads to ensure adequate flow.
Check that the cold inlet isolation valve to the boiler is fully open.

Professional actions:

An engineer will test the DHW flow sensor, inspect and free or replace the diverter valve, and clean inlet filters.

Medium 3/5

Diverter Valve Assembly

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