B-1 High

Ferroli B-1 Fault Code

Also written as B1 — same fault.

The Ferroli B-1 fault code means: your boiler has lost its power supply, which could be due to a tripped switch, a disconnected plug, or a blown fuse.. It appears on 2 Ferroli 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: No main electricity/switches off, fuse blown.
Typical repair cost £80-150 (including labour)

DIY fix possible

Check that your boiler's power switch or fused spur is switched to the ON position.Check your home's main consumer unit (fuse box) to see if the boiler's circuit breaker has tripped.Ensure the plug or fused spur connection is securely connected and that the fuse inside the spur has not failed.

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Ferroli models that show the B-1 fault code

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

Source

Ferroli B-1 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