BoilerFaultCodesBiasi 04E Fault Code
The Biasi 04E fault code means: your boiler has detected that water is not circulating correctly through the system, which is preventing it from heating your home or water safely.. It appears on 2 Biasi models in our database.
Technical description: Faulty primary circuit (no water or absence ol fl ow)
DIY fix possible
Check the pressure gauge on the front of the boiler; if it is below 1 bar, locate the filling loop under the boiler.Open the filling loop valves to top up the system pressure until the gauge reads between 1 and 1.5 bar.Close the valves tightly and restart the boiler.
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Biasi models that show the 04E fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Biasi 04E 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 7 July 2026