E40 High

Biasi E40 Fault Code

The Biasi E40 fault code means: your boiler has detected an issue with the electrical power supply coming from the mains, meaning the electricity is not stable enough for the boiler to operate safely.. It appears on 5 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: Mains supply voltage frequency error
Typical repair cost £100-£350 (including labour)

Engineer required

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

Find a Gas Safe engineer

Search the official register for a qualified engineer in your area.

Gas Safe Register →

Biasi models that show the E40 fault code

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

Source

Biasi E40 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