BoilerFaultCodesThe 6 most common faults
Your boiler has stopped working for safety reasons and needs to be manually restarted to try and fire up again.
Locate the reset push-button on the front control panel.Press and hold the button for a few seconds until the red light goes out.Check that your gas supply is active and your prepaid meter has credit.
Your boiler has shut down completely for safety because it failed to light or stay lit after several attempts.
Check if your gas supply is active and credit is on the meterPress the 'Reset' button (located next to the lockout lamp) for five secondsMonitor if the blue burner light stays on after the reset
Your boiler is not receiving the gas it needs to create a flame, causing the system to shut down for safety.
Check if other gas appliances in your home, such as a hob, are working correctly.Ensure your gas meter has credit if you use a prepay meter.Check that the gas isolation valve under the boiler is in the 'on' or 'open' position.Try resetting the boiler by turning the selector knob to the 'R' position for a few seconds.
Your boiler is unable to light the flame needed to heat your water or radiators, causing the system to shut down for safety.
Full guide for Faulty ignitionYour boiler is struggling to detect if the burner has successfully lit, which has caused the system to shut down for safety.
Full guide for Faulty flame detectionYour boiler has stopped working because the small nozzles that deliver gas to the burner have become blocked, preventing the flame from starting safely.
Full guide for Gas injectors pluggedon the Biasi Prisma
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