BoilerFaultCodesThe 6 most common faults
Your boiler has failed to light the flame, which means you currently have no heating or hot water.
Why it happens: This fault occurs when the boiler's control system attempts to light the burner but fails to detect a steady flame after several tries. The most common reasons include a worn-out ignition spark electrode that can no longer create a spark, or a gas valve that isn't opening correctly to allow fuel into the burner.
Check if other gas appliances in your home, like a hob, are working to ensure gas is reaching the property.Verify that your gas prepaid meter has credit, if applicable.Press the 'Reset' button on the boiler control panel once to see if the system restarts.
Your boiler has likely overheated because the water isn't moving through the system properly or a safety sensor has detected a temperature that is too high.
Why it happens: This fault occurs when the water inside the boiler exceeds a safe temperature, triggering a safety shutdown. The most common reasons are a pump failure that prevents water from moving, or a buildup of debris and sludge that blocks the heat exchanger.
Check that your radiator valves and isolation valves are fully openEnsure your system pressure is topped up to between 1 and 1.5 barPress the Reset button on the control panel to see if the fault clears
Your boiler has stopped working because the water pressure inside the system has dropped too low to operate safely.
Why it happens: This fault occurs when the internal water pressure drops below the minimum level required for the boiler to fire up safely. The most common reason is a slow leak somewhere in your radiator network or a faulty expansion vessel that can no longer manage the system's pressure. It can also happen if you have recently bled your radiators and haven't topped the water level back up.
Locate the filling loop (usually a silver flexible hose) underneath or near the boiler.Slowly open the one or two small valves on the filling loop to allow water into the system.Watch the pressure gauge and close the valves tightly once the needle reaches between 1.0 and 1.5 bar.
Your boiler has stopped working because water is not moving through it properly or there is trapped air causing it to overheat.
Why it happens: This fault occurs when the boiler detects that heat is not being carried away from the heat exchanger fast enough, causing it to reach a dangerously high temperature. The most common reasons are a failed pump that isn't pushing water around, or a buildup of air and sludge that is blocking the flow within the pipes.
Check that your system pressure is between 1 and 1.5 bar on the pressure gaugeBleed all radiators in your home to remove trapped airEnsure all radiator valves and external isolation valves are fully open
Your boiler has sensed it is getting too hot too quickly and has shut down to protect its internal parts from damage.
Why it happens: This fault occurs when the boiler's internal components detect a rapid, unsafe rise in temperature that cannot be dissipated. It is usually caused by a blockage in the pipework, a buildup of air, or a pump that has failed and stopped moving water through the system. In some cases, the temperature sensor itself may be faulty and providing an incorrect reading to the control board.
Check that your radiator valves are open and not turned to the off position.Ensure the boiler pressure is between 1.0 and 1.5 bar on the pressure gauge.Try bleeding your radiators to remove any trapped air that might be blocking water flow.
Your boiler thinks it sees a flame even though it hasn't started the burner yet, which is a safety conflict that prevents it from running.
Why it happens: This fault occurs when the boiler's internal sensor detects an electrical signal mimicking a flame before the heating cycle has actually started. This is usually caused by a carbon-coated or damaged electrode sending a 'false' signal, or moisture and debris on the burner assembly interfering with the detection system.
Full guide for A02on the Ferroli Modena HE
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