Baxi
No Demand Recognition / Flow Detection Failure
No hot water at any tap, Baxi water heater appears powered but burner does not ignite when a hot tap is opened.
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Safety Warning
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.
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Possible Causes
Faulty water flow sensor on Baxi water module, Blocked inlet filter reducing flow below minimum, Stuck flow switch or turbine, Very low mains water pressure
How to Fix / Troubleshooting
Safety: Turn off power and close the cold water isolation valve before opening water connections.
Steps:
- Check other taps: Confirm that cold water pressure is normal at other outlets.
- Clean inlet filter: Close the cold inlet valve to the heater. Remove the union and clean the mesh filter in the Baxi inlet assembly.
- Check minimum flow: Some Baxi models require a minimum flow rate to start. Fully open the hot tap and see if the unit attempts to start.
- Flow sensor/turbine: If comfortable, remove and inspect the flow sensor/turbine for debris or limescale. Clean and ensure free movement.
Professional: If the unit still does not detect demand, the flow sensor or control PCB may need replacement.
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Repair Difficulty
Medium
3/5
Required Part
Water Flow Sensor / Turbine Assembly
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