BoilerFaultCodesThe 6 most common faults
Your boiler has stopped working because the water pressure inside the heating system has dropped too low to operate safely.
Locate the external filling loop, which is a silver braided flexible hose connected between two pipes under your boiler.Open the small black or blue valves on either end of the hose to allow mains water to enter the system.Watch the pressure gauge on the front of the boiler until the needle reaches the green zone (usually between 1.0 and 1.5 bar), then tightly close both valves.
Your boiler has detected that the water pressure level inside your heating system is currently too high or too low for it to operate safely.
Check the system pressure gauge on the front of the boiler.If the pressure is below 1 bar, locate the filling loop to top up water until the needle reaches 1.5 bar.If the pressure is above 2.5 bar, bleed a radiator elsewhere in your home to release excess pressure.
Your boiler has lost the ability to accurately measure the temperature of the water being sent to your radiators, so it has shut down to prevent overheating.
Full guide for F10Your boiler has detected that the electricity supply reaching it is too low to operate safely, causing it to shut down to prevent damage.
Full guide for F34Your boiler is struggling because the electricity supply it is receiving from your home is unstable or not at the correct frequency.
Full guide for F35Your boiler's sensor is failing to detect the water pressure, so it has shut down to prevent damage to the system.
Full guide for F47on the Ferroli Atlas D
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 Ferroli 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