BoilerFaultCodesThe 6 most common faults
Your boiler has stopped working because the water pressure inside the heating system has dropped too low.
Locate the filling loop (usually a silver braided hose with one or two valves) underneath the boiler.Open the valve(s) to allow mains water into the system until the pressure gauge on the front of the boiler reads between 1.0 and 1.5 bar.Close the valve(s) tightly and check that the error code has cleared.
Your boiler has detected that it is dangerously hot and has shut itself down to prevent damage.
Check that all your radiators have their valves fully opened to allow water to flow through the systemCheck the boiler pressure gauge to ensure it is between 1 and 1.5 bar, and repressurize if it is too lowBleed your radiators to remove any trapped air that might be blocking water circulation
Your boiler has detected that the water pressure in your heating system has dropped too low to operate safely.
Locate the external filling loop, which is usually a flexible silver hose connecting two pipes underneath the boiler.Open the small valve(s) on the loop to let water back into the system while watching the pressure gauge on the front panel.Close the valves firmly once the needle sits between 1 bar and 1.5 bar, then restart your boiler.
Your boiler has detected that the water pressure inside your heating system is too high, which prevents it from operating safely.
Locate a radiator in your home, preferably one upstairs.Place a cloth or small container under the radiator bleed valve.Use a radiator key to slowly open the valve just enough to let water drip out.Monitor your boiler's pressure gauge until the needle drops into the green zone (typically 1.0 to 1.5 bar) and then tighten the valve.
Your boiler is failing to light the flame needed to produce heat or hot water.
Full guide for A01Your boiler is trying to start but failing to light the flame, which means it has now locked itself out for safety reasons.
Full guide for A06on the Ferroli Extrema C
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