Ferroli BlueHelix Pro 25C Fault codes & diagnostics

39 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.

Combi Natural GasLPG 25 kW 2016-2020 Discontinued

Replaced by: BlueHelix Tech RRT

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Severity at a glance

Each cell = one fault code. Hover to identify.
4 Emergency 33 High 1 Medium 1 Low
Just want the most common Ferroli BlueHelix Pro 25C faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes

All 39 documented codes

Tap any card for details

A01

Your boiler has failed to light the flame, which means you currently have no heating or hot water.

High DIY-safe £100-350

What to check first

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

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • Ignition lead
  • PCB

Related codes

Full explanation for A01
A02

Your boiler detects a flame when it should be turned off, which prevents the system from starting up safely.

High Engineer only £120-280

Parts commonly replaced

  • Ionisation electrode
  • Main control board
  • Gas valve

Related codes

Full explanation for A02
A05

Your boiler has stopped working because the internal fan, which safely removes waste gases, is not spinning at the correct speed.

High Engineer only £280-450

Parts commonly replaced

  • Fan assembly
  • Main PCB
  • Wiring harness
Full explanation for A05
A06

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

High DIY-safe £120-350

What to check first

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

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • Detection electrode

Related codes

Full explanation for A06
A07

Your boiler has shut down because the exhaust fumes have become dangerously hot, which could indicate a blockage or a heat exchanger problem.

Emergency Engineer only £150-550

Parts commonly replaced

  • Heat Exchanger
  • Flue Gas NTC Sensor
  • Main Heat Exchanger Cleaning Kit

Related codes

Full explanation for A07
A08

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

High DIY-safe £120-350

What to check first

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

Parts commonly replaced

  • Circulation Pump
  • Heat Exchanger (Cleaning/Descaling)
  • NTC Temperature Sensor

Related codes

Full explanation for A08
A09

Your boiler has sensed it is getting much too hot and has shut itself down to prevent damage or dangerous overheating.

High Engineer only £120-350

Parts commonly replaced

  • Circulation pump
  • Overheated limit thermostat
  • Heat exchanger cleaning

Related codes

Full explanation for A09
A10

Your boiler's internal sensor has stopped correctly monitoring the water temperature as it leaves the unit, preventing it from heating up properly.

High Engineer only £90-180

Parts commonly replaced

  • NTC Flow Sensor
  • Wiring Harness
  • Main PCB

Related codes

Full explanation for A10
A11

Your boiler has stopped working because it can no longer accurately measure the temperature of the water coming back from your radiators.

High Engineer only £100-£180

Parts commonly replaced

  • Return NTC temperature sensor
  • Wiring harness

Related codes

Full explanation for A11
A13

Your boiler has detected an issue with the sensor that monitors exhaust gases, causing the system to lock down for safety.

High Engineer only £120-220

Parts commonly replaced

  • Flue Gas Probe (NTC sensor)
  • Wiring Harness
  • Main PCB

Related codes

Full explanation for A13
Showing 11–20 of 39
A14

Your boiler has shut down because it has detected a problem with how the exhaust fumes are being cleared from the property.

Emergency Engineer only £120-350

Parts commonly replaced

  • Pressure switch
  • Fan
  • Flue seals

Related codes

Full explanation for A14
A42

Your boiler has detected an unusual temperature difference between its sensors and has shut down to prevent any internal damage.

High Engineer only £120-250

Parts commonly replaced

  • Flow temperature sensor
  • Return temperature sensor
  • Circulation pump

Related codes

Full explanation for A42
A54

Your boiler's internal computer has encountered a critical electronic failure and can no longer control the heating or hot water safely.

High Engineer only £250-£450

Parts commonly replaced

  • Main PCB (Printed Circuit Board)
  • Wiring Loom
Full explanation for A54
A55

Your boiler's internal computer has encountered a critical electronic failure and can no longer control the heating or hot water safely.

High Engineer only £250-£450

Parts commonly replaced

  • Main PCB (Printed Circuit Board)
  • Wiring Loom
Full explanation for A55
A56

Your boiler is having trouble setting up its gas and air mixture correctly, which prevents it from firing up safely.

High DIY-safe £100-350

What to check first

  1. Check that your gas supply is turned on and other gas appliances are working
  2. Press and hold the 'Reset' button for 5 seconds to clear the fault
  3. Allow the boiler to attempt its automatic calibration sequence for several minutes

Parts commonly replaced

  • Gas valve
  • Ionisation electrode
  • PCB (Control board)
Full explanation for A56
A61

Your boiler's internal computer brain has detected a serious electronic failure and can no longer control the heating software correctly.

High Engineer only £300-£550

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Wiring Harness

Related codes

Full explanation for A61
A62

Your boiler has switched itself off because the main control board is unable to talk to the gas valve that fuels the flames.

High Engineer only £180-450

Parts commonly replaced

  • Gas Valve
  • PCB (Main Control Board)
  • Wiring Harness

Related codes

Full explanation for A62
A63

Your boiler's internal computer has encountered a critical electronic failure and can no longer control the heating or hot water safely.

High Engineer only £250-£450

Parts commonly replaced

  • Main PCB (Printed Circuit Board)
  • Wiring Loom
Full explanation for A63
A64

Your boiler has been manually reset too many times in a short period and has now locked itself out for safety.

High Engineer only £100-250

Parts commonly replaced

  • Ignition Electrodes
  • Gas Valve
  • Printed Circuit Board (PCB)

Related codes

Full explanation for A64
A68

Your boiler's internal memory card or control chip is failing to communicate correctly with the main computer board.

High Engineer only £180-350

Parts commonly replaced

  • Boiler Chip Card (BCC)
  • Main PCB (Printed Circuit Board)

Related codes

Full explanation for A68
Showing 21–30 of 39
F07

Your boiler has shut down because the exhaust fumes have become dangerously hot, which could indicate a blockage or a heat exchanger problem.

Emergency Engineer only £150-550

Parts commonly replaced

  • Heat Exchanger
  • Flue Gas NTC Sensor
  • Main Heat Exchanger Cleaning Kit

Related codes

Full explanation for F07
F08

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

High DIY-safe £120-350

What to check first

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

Parts commonly replaced

  • Circulation Pump
  • Heat Exchanger (Cleaning/Descaling)
  • NTC Temperature Sensor

Related codes

Full explanation for F08
F09

Your boiler has sensed it is getting much too hot and has shut itself down to prevent damage or dangerous overheating.

High Engineer only £120-350

Parts commonly replaced

  • Circulation pump
  • Overheated limit thermostat
  • Heat exchanger cleaning

Related codes

Full explanation for F09
F10

Your boiler's internal sensor has stopped correctly monitoring the water temperature as it leaves the unit, preventing it from heating up properly.

High Engineer only £90-180

Parts commonly replaced

  • NTC Flow Sensor
  • Wiring Harness
  • Main PCB

Related codes

Full explanation for F10
F11

Your boiler has stopped working because it can no longer accurately measure the temperature of the water coming back from your radiators.

High Engineer only £100-£180

Parts commonly replaced

  • Return NTC temperature sensor
  • Wiring harness

Related codes

Full explanation for F11
F12

Your boiler's hot water sensor has stopped working, meaning the system cannot accurately monitor the temperature of the water coming out of your taps.

Medium Engineer only £90-160

Parts commonly replaced

  • Domestic Hot Water (DHW) NTC Sensor
  • Sensor wiring harness

Related codes

Full explanation for F12
F13

Your boiler has detected an issue with the sensor that monitors exhaust gases, causing the system to lock down for safety.

High Engineer only £120-220

Parts commonly replaced

  • Flue Gas Probe (NTC sensor)
  • Wiring Harness
  • Main PCB

Related codes

Full explanation for F13
F14

Your boiler has shut down because the exhaust fumes have become dangerously hot, which could indicate a blockage or a heat exchanger problem.

Emergency Engineer only £150-550

Parts commonly replaced

  • Heat Exchanger
  • Flue Gas NTC Sensor
  • Main Heat Exchanger Cleaning Kit

Related codes

Full explanation for F14
F34

Your boiler has stopped working because the electrical power supply coming into your home is currently too low for the system to operate safely.

High Engineer only £100-350

Parts commonly replaced

  • Main PCB
  • Power Supply Unit

Related codes

Full explanation for F34
F37

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

High DIY-safe £60-120

What to check first

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

Parts commonly replaced

  • Filling loop
  • Pressure sensor
  • Expansion vessel

Related codes

Full explanation for F37
Showing 31–39 of 39
F39

Your boiler's outside temperature sensor has developed a fault or disconnected, meaning the system may struggle to automatically adjust its heating levels based on the weather.

Low Engineer only £90-160

Parts commonly replaced

  • External weather compensation probe
  • Wiring harness

Related codes

Full explanation for F39
F41

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.

High DIY-safe £100-£350

What to check first

  1. Check that your boiler pressure is between 1.0 and 1.5 bar
  2. Ensure all radiator valves and isolation valves are fully open
  3. Check for any air trapped in the system and bleed your radiators

Parts commonly replaced

  • Circulation Pump
  • Temperature Sensors (NTC)
  • Main Heat Exchanger (if blocked)

Related codes

Full explanation for F41
F42

Your boiler has detected an unusual temperature difference between its sensors and has shut down to prevent any internal damage.

High Engineer only £120-250

Parts commonly replaced

  • Flow temperature sensor
  • Return temperature sensor
  • Circulation pump

Related codes

Full explanation for F42
F43

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

High DIY-safe £120-£450

What to check first

  1. Check that your home heating system pressure is between 1.0 and 1.5 bar
  2. Ensure all radiator valves and isolation valves are fully open
  3. Try resetting the boiler using the 'R' button once the unit has cooled down

Parts commonly replaced

  • Central heating pump
  • Heat exchanger (descaling)
  • Temperature sensor (NTC thermistor)
Full explanation for F43
F56

Your boiler is having trouble setting up its gas and air mixture correctly, which prevents it from firing up safely.

High DIY-safe £100-350

What to check first

  1. Check that your gas supply is turned on and other gas appliances are working
  2. Press and hold the 'Reset' button for 5 seconds to clear the fault
  3. Allow the boiler to attempt its automatic calibration sequence for several minutes

Parts commonly replaced

  • Gas valve
  • Ionisation electrode
  • PCB (Control board)
Full explanation for F56
F61

Your boiler's internal computer brain has detected a serious electronic failure and can no longer control the heating software correctly.

High Engineer only £300-£550

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Wiring Harness

Related codes

Full explanation for F61
F66

Your boiler's main control board has detected an internal communication error, meaning it cannot process commands correctly.

High Engineer only £250-450

Parts commonly replaced

  • Main PCB
  • Wiring Harness

Related codes

Full explanation for F66
F67

Your boiler's computer or main control board has experienced a hardware error and cannot communicate with the rest of the system.

High DIY-safe £250-450

What to check first

  1. Locate the electrical spur or plug for the boiler
  2. Switch the power off for at least 30 seconds
  3. Switch the power back on and press the 'Reset' button on the control panel

Parts commonly replaced

  • Main PCB (Printed Circuit Board)
  • Wiring Loom

Related codes

Full explanation for F67
F68

Your boiler's internal memory card or control chip is failing to communicate correctly with the main computer board.

High Engineer only £180-350

Parts commonly replaced

  • Boiler Chip Card (BCC)
  • Main PCB (Printed Circuit Board)

Related codes

Full explanation for F68