How much does it cost to fix Biasi error code Er 04?

Typical repair cost for the Biasi Er 04 fault is £100-280 including labour.

Er 04 High

Biasi Er 04 Fault Code

Q: What does the Biasi Er 04 fault code mean?

Your boiler has detected that there is either not enough water in the system or the water isn't moving through the pipes correctly.

Also written as ER04 — same fault.

The Biasi Er 04 fault code means: your boiler has detected that there is either not enough water in the system or the water isn't moving through the pipes correctly.. It appears on 2 Biasi models in our database.

Technical description: Faulty primary circuit (no water or absence of flow)

Typical repair cost £100-280 (including labour)

DIY fix possible

Check the pressure gauge on the front of the boiler; it should be between 1 and 1.5 bar.If the pressure is too low, use the filling loop underneath the boiler to top it up with water.Ensure all radiator valves and isolation valves under the boiler are fully open.

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Biasi models that show the Er 04 fault code

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

Source

Biasi Er 04 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