E77 Medium

Biasi E77 Fault Code

The Biasi E77 fault code means: your boiler's control system is struggling to adjust the flame size correctly, which may lead to inefficient heating or the unit shutting down.. It appears on 3 Biasi models in our database.

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

Technical description: System out modulator control parameters.
Typical repair cost £120-£350 (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 E77 fault code

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

Source

Biasi E77 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