Er 12 High

Biasi Er 12 Fault Code

Also written as ER12 — same fault.

The Biasi Er 12 fault code means: your boiler has stopped working because a sensor that measures the temperature of the water returning to the system is failing to send a signal, causing the boiler to shut down as a precaution.. It appears on 7 Biasi models in our database.

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description: Fauty c.h. temp. probe NTC return
Typical repair cost £120-200 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Biasi models that show the Er 12 fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Biasi Er 12 fault code information on this page is sourced and cross-checked against the official Biasi service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 31 August 2026