BoilerFaultCodesThe 6 most common faults
01
Faulty primary circuit High Engineer
Your boiler has detected that water isn't flowing properly through its internal heating pipes, so it has safely shut down to prevent damage.
Full guide for Faulty primary circuit02
Faulty air pressure switch High Engineer
Your boiler has stopped working because it cannot safely confirm that exhaust gases are clearing properly.
Full guide for Faulty air pressure switch03
Lack of burner ignition High Engineer
Your boiler is trying to start up, but it is failing to light the flame safely.
Full guide for Lack of burner ignition04
Safety thermostat lockout High Engineer
Your boiler has shut itself down safely because it detected that internal temperatures became too high.
Full guide for Safety thermostat lockout05
Lack of power supply or faulty electr. control p.c.b. High Engineer
Your boiler is not receiving any electrical power or the main electronic brain has stopped working properly.
Full guide for Lack of power supply or faulty electr. control p.c.b.06
Excessive temperature on primary circuit Emergency Engineer
Your boiler has automatically shut down because the water inside it has become dangerously hot.
Full guide for Excessive temperature on primary circuiton the Biasi Parva HE Combi
Circulating pumpAutomatic bypass valvePlate heat exchangerAir pressure switchPressure switch silicone tubesFlue terminal
Based on parts cited in our fault code database. Your engineer will confirm what's actually needed after diagnosis.
Call a Gas Safe engineer if…
- You can smell gas or see signs of a leak
- The Biasi shows an Emergency or High severity code
- The boiler keeps locking out after repeated resets
- You've tried the DIY checks and the fault hasn't cleared
- There's visible water leaking from the boiler
- The flame is yellow or orange instead of blue
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