What does the Biasi E04 fault code mean?

Your boiler has detected that the water pressure is too low or isn't circulating properly, which prevents it from heating up safely.

How much does it cost to fix Biasi error code E04?

Typical repair cost for the Biasi E04 fault is £100-£220 including labour.

Locate the pressure gauge on the front of the boiler and check if the needle is below 1.0 bar (typically in the red zone).

Circulation/water pressure failure (Primary circuit pressure switch)

This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

Six most common causes of dropping pressure.

Step-by-step using the filling loop.

Each noise points to a different fault.