Common problems guide

The most common Ferroli boiler problems

The faults we see most often across the Ferroli range — with plain-English causes, what to check first, estimated repair costs, and whether it's a DIY job or needs a Gas Safe engineer. Based on fault-code data across 28 Ferroli boiler models.

355 unique codes
28 models covered
8 DIY-safe (top 8)
8 engineer needed

The most common Ferroli faults

01
A01 High DIY-safe

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 attempts to start up but cannot confirm that a flame has been established. The most common reasons are a lack of gas reaching the burner, a worn-out ignition spark, or a sensor failing to detect the heat even if the flame did briefly light.

What to try first

Check if your gas supply is turned on and other gas appliances are workingPress the 'Reset' button on the boiler control panel for 1 secondCheck that your condensate pipe (outside) has not frozen during cold weather

Est. cost
£100-350
Parts
Ignition electrode, Gas valve, Ignition lead
Full guide for Bluehelix Tech A01
02
A06 High DIY-safe

Your boiler is failing to stay lit after it tries to start up, meaning it cannot provide you with heating or hot water.

Why it happens: This fault occurs when the boiler successfully creates a spark and ignites the gas, but then fails to detect that the flame is actually burning. The most common reasons are a dirty or worn-out detection sensor that can't 'see' the fire, or a faulty gas valve that isn't providing a steady enough flow of fuel to keep the flame stable.

What to try first

Check that your gas supply is turned on at the meterCheck if other gas appliances, like a hob, are working correctlyReset the boiler by pressing the 'Reset' button for 1 second

Est. cost
£120-350
Parts
Ignition electrode, Gas valve, Detection electrode
Full guide for Bluehelix Tech A06
03
F08 High DIY-safe

Your boiler has sensed that parts of the internal system have become too hot, causing it to shut down automatically to prevent damage.

Why it happens: This fault occurs when the internal temperature of the boiler rises above a safe limit, usually because water isn't moving through the system fast enough to carry heat away. The most common reasons are a failing circulation pump, a build-up of sludge or limescale blocking the heat exchanger, or a 'pocket' of air trapped within the unit.

What to try first

Check that your radiator valves are open to allow water to circulate.Ensure there is enough water pressure in the system (typically 1.0 to 1.5 bar).Press the 'Reset' button on the control panel to see if the fault clears.

Est. cost
£120-350
Parts
Circulation Pump, Heat Exchanger (Cleaning/Descaling), NTC Temperature Sensor
Full guide for Bluehelix Tech F08
04
A08 High DIY-safe

Your boiler has sensed that parts of the internal system have become too hot, causing it to shut down automatically to prevent damage.

Why it happens: This fault occurs when the internal temperature of the boiler rises above a safe limit, usually because water isn't moving through the system fast enough to carry heat away. The most common reasons are a failing circulation pump, a build-up of sludge or limescale blocking the heat exchanger, or a 'pocket' of air trapped within the unit.

What to try first

Check that your radiator valves are open to allow water to circulate.Ensure there is enough water pressure in the system (typically 1.0 to 1.5 bar).Press the 'Reset' button on the control panel to see if the fault clears.

Est. cost
£120-350
Parts
Circulation Pump, Heat Exchanger (Cleaning/Descaling), NTC Temperature Sensor
Full guide for Bluehelix Tech A08
05
F37 High DIY-safe

Your boiler has stopped working because the water pressure inside the system is too low.

Why it happens: This fault occurs when the water pressure inside your heating system drops below the minimum level required for the boiler to operate safely. The most common reasons for this are a leak somewhere in the pipework or radiators, or because you have recently bled your radiators without topping the water back up.

What to try first

Locate the filling loop (usually a silver flexible hose) under or near the boiler.Slowly open the valve or valves until you hear water flowing into the system.Watch the pressure gauge and close the valves once the needle reaches 1.5 bar.

Est. cost
£60-120
Parts
Filling loop, Pressure sensor, Expansion vessel
Full guide for Bluehelix Tech F37
06
F39 High DIY-safe

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.

What to try first

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.

Est. cost
£90-180
Parts
Temperature Sensor (NTC thermistor), Circulation Pump, Main Heat Exchanger (if scaled)
Full guide for Modena HE F39
07
F41 High DIY-safe

Your boiler has sensed that the temperature is rising too quickly inside the unit, often caused by water not flowing through the pipes fast enough.

Why it happens: This fault occurs when the boiler's internal sensors detect that the heat is increasing much faster than the water can carry it away. The most common reason is a restriction in water flow, often caused by a failing pump or a build-up of sludge and debris blocking the narrow pipes inside the heat exchanger.

What to try first

Check that your boiler pressure is between 1.0 and 1.5 barEnsure all radiator valves and isolation valves are fully openCheck for any air trapped in the system and bleed your radiators

Est. cost
£100-£350
Parts
Circulation Pump, Temperature Sensors (NTC), Main Heat Exchanger (if blocked)
Full guide for Bluehelix Tech F41
08
F43 High DIY-safe

Your boiler has shut down to prevent the heat exchanger from overheating, often because the water isn't flowing through the system correctly.

Why it happens: This fault occurs when the boiler's internal sensors detect that the heat exchanger is getting too hot too quickly, which usually indicates that water isn't moving through the unit fast enough to carry the heat away. The most common reason is a failing internal pump or a build-up of sludge and debris that is restricting the flow of water through the system. In some cases, it can also be caused by air trapped in the heat exchanger or a faulty temperature sensor giving an incorrect reading.

What to try first

Check that your home heating system pressure is between 1.0 and 1.5 barEnsure all radiator valves and isolation valves are fully openTry resetting the boiler using the 'R' button once the unit has cooled down

Est. cost
£120-£450
Parts
Central heating pump, Heat exchanger (descaling), Temperature sensor (NTC thermistor)
Full guide for Bluehelix Tech F43