How much does it cost to fix Biasi error code 90˚C?

Typical repair cost for the Biasi 90˚C fault is £100-250 including labour.

90˚C Medium

Biasi 90˚C Fault Code

Q: What does the Biasi 90˚C fault code mean?

Your boiler is overheating because the water inside is getting too hot, causing it to automatically turn down its power to prevent damage.

Also written as 90C — same fault.

The Biasi 90˚C fault code means: your boiler is overheating because the water inside is getting too hot, causing it to automatically turn down its power to prevent damage.. It appears on 1 Biasi model in our database.

Technical description: Primary circuit temperature over 90°C (useful output is automatically reduced)

Typical repair cost £100-250 (including labour)

DIY fix possible

Check that all radiator valves are fully open to allow water to flow.Ensure the boiler pressure gauge is between 1 and 1.5 bar.Reset the boiler using the control knob to see if the fault clears.

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Biasi models that show the 90˚C fault code

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

Activa Repair: £100-250

Source

Biasi 90˚C 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 27 April 2026