How much does it cost to fix Ferroli error code B LED 4?

Typical repair cost for the Ferroli B LED 4 fault is £120-200 including labour.

B LED 4 High

Ferroli B LED 4 Fault Code

Q: What does the Ferroli B LED 4 fault code mean?

Your boiler has stopped working because it cannot correctly sense its own temperature, likely due to a loose wire or a faulty temperature probe.

Also written as BLED4 — same fault.

The Ferroli B LED 4 fault code means: your boiler has stopped working because it cannot correctly sense its own temperature, likely due to a loose wire or a faulty temperature probe.. It appears on 2 Ferroli models in our database.

Technical description: - Central heating sensor (34) not connected or - boiler temperature too high or - boiler thermostat (61) below CH temperature

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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Ferroli models that show the B LED 4 fault code

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

Source

Ferroli B LED 4 fault code information on this page is sourced and cross-checked against the official Ferroli service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026