Biasi Return NTC Sensor Fault

Boiler displays error 08; there is no heating, the pump may run continuously, and the temperature display may be fixed at a low or high value.

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 return temperature sensor, broken or shorted sensor wiring, poor contact between the sensor and pipe, PCB input fault.

Safety: Turn off power and allow the system to cool before touching pipework.

Visual inspection: Locate the return NTC on the return pipe or hydraulic block. Check that it is firmly attached and that the wiring harness is not damaged.
Check connectors: Reseat the plug at the sensor and at the PCB to eliminate poor contact.
Engineer diagnostics: A technician should measure the NTC resistance and compare it with the flow NTC at the same temperature. Large discrepancies indicate a faulty sensor.
Replace sensor if needed: If the NTC is confirmed faulty, it can usually be replaced without draining if it is a clip-on type; immersion types may require draining or isolating the boiler.

Medium 3/5

Return NTC Sensor

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