07
Biasi
DHW NTC Sensor Fault
Boiler shows error 07, hot water temperature unstable or boiler cycles rapidly on DHW demand.
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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 domestic hot water NTC sensor, Loose sensor connection on DHW outlet, Scale build-up in plate heat exchanger affecting sensor reading, Faulty PCB
How to Fix / Troubleshooting
Safety: Isolate power and water supply before removing any DHW components.
- Check DHW temperature behaviour: Note if water runs hot then cold repeatedly, or if the display shows unrealistic temperatures.
- Inspect DHW NTC: Locate the DHW NTC on the domestic hot water outlet or plate heat exchanger on your Biasi boiler. Ensure the sensor is firmly clipped and the wiring is intact.
- Engineer resistance test: A technician should measure the NTC resistance and compare it to the Biasi chart. Replace if out of tolerance.
- Check for scale: In hard water areas, the plate heat exchanger and sensor pocket can scale up. An engineer may need to chemically descale or replace the plate heat exchanger.
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Repair Difficulty
Hard
4/5
Required Part
DHW NTC Sensor
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