BoilerFaultCodesThe 6 most common faults
Your boiler has detected that water is not flowing properly around your heating system, usually because the pressure is too low or a pump has stopped working.
Check the pressure gauge on the front of your boiler; if it is below 1.0 bar, use the filling loop to top it up to between 1.0 and 1.5 bar.Ensure your heating controls and thermostat are calling for heat.Restart the boiler using the reset button or dial.
Your boiler has detected that there is not enough water circulating inside it to work safely, so it has shut down to prevent damage.
Check the pressure gauge on the front of the boiler; if it is below 1 bar, your system needs topping up.Locate the external filling loop (or internal key) usually found underneath the boiler.Slowly open the valve to let water into the system until the gauge reads between 1 and 1.5 bar, then tighten the valve firmly.
Your boiler has failed to light the flame and has turned itself off for safety reasons, meaning you currently have no heating or hot water.
Full guide for Er 01Your boiler has detected that it has become dangerously hot and has automatically shut down to prevent damage or overheating.
Full guide for Er 02Your boiler has detected a general internal fault that has caused it to shut down for safety reasons.
Full guide for Er 03Your boiler is unable to safely clear exhaust gases because the internal fan mechanism is not responding correctly.
Full guide for Er 05on the Biasi Advance Plus 16S
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
Avoid the next call-out bill
Monthly cover means no unexpected bills when your boiler breaks down.
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