Ferroli Bluehelix Pro RRT Fault codes & diagnostics

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

System Natural GasLPG 18-30 kW 2019-present

The Bluehelix Pro RRT range comes in 3 types

Pick the one you have. The fault codes, GC numbers and manual differ by type.

Each model has its own manual A family spans several manuals, one per model or generation. Pick your model above and its page has the manual its fault codes were read from.

The fault code is already on your display

Note it down before pressing reset — resetting clears the code immediately. How to read fault codes →

Severity at a glance

Each cell = one fault code. Hover to identify.
2 Emergency 46 High 3 Low

All 51 documented codes

Tap any card for details

A01

Your boiler is failing to light the flame, which means it cannot produce any hot water or heating.

High Engineer only £120-250 Shared across the PRO RRT range

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • Ignition lead

Related codes

A02

Your boiler has detected that a flame is present when it should be switched off, which is a safety concern that requires an immediate professional check.

Emergency Engineer only £150-300 Shared across the PRO RRT range

Parts commonly replaced

  • Gas valve
  • Ionisation electrode
  • Printed circuit board (PCB)

Related codes

A05

Your boiler is unable to safely vent exhaust gases because the internal fan that pushes air through the system has stopped working correctly.

High Engineer only £180-350 Shared across the PRO RRT range

Parts commonly replaced

  • Fan assembly
  • Wiring harness
  • PCB

Related codes

A06

Your boiler is failing to light the internal burner, so it has safely shut itself down to prevent a gas build-up.

High Engineer only £150-300 Shared across the PRO RRT range

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • PCB

Related codes

A07

Your boiler has detected that the exhaust gases leaving the unit are getting too hot, so it has shut itself down to prevent damage to internal parts.

High Engineer only £150-350 Shared across the PRO RRT range

Parts commonly replaced

  • Primary heat exchanger
  • Flue gas temperature sensor
  • Burner assembly

Related codes

A08

Your boiler has detected that the water inside it has become dangerously hot and has shut itself down to prevent damage.

High Engineer only £120-250 Shared across the PRO RRT range

Parts commonly replaced

  • NTC temperature sensor
  • System pump
  • Heat exchanger

Related codes

A09

Your boiler has detected that it is getting dangerously hot and has shut itself down to prevent damage.

High Engineer only £150-350 Shared across the PRO RRT range

Parts commonly replaced

  • System filter
  • Central heating pump
  • Heat exchanger
  • NTC sensor

Related codes

A10

Your boiler is failing to detect the flow of water through the system, which means it cannot safely start up to provide you with heating or hot water.

High Engineer only £150-250 Shared across the PRO RRT range

Parts commonly replaced

  • Flow sensor
  • Wiring harness

Related codes

A11

Your boiler is having trouble 'reading' the temperature of the water returning to it, so it has stopped working as a safety precaution to prevent overheating.

High Engineer only £120-220 Shared across the PRO RRT range

Parts commonly replaced

  • Return temperature sensor
  • Wiring harness

Related codes

A13

Your boiler has detected an issue with the sensor that monitors the temperature of the gases leaving your flue, causing it to shut down for safety.

High Engineer only £120-220 Shared across the PRO RRT range

Parts commonly replaced

  • Flue gas temperature sensor
  • Wiring harness

Related codes

Showing 11–20 of 51
A14

Your boiler has detected an issue with the air or exhaust system, meaning it cannot safely push fumes outside, so it has shut down to protect you.

Emergency Engineer only £150-300 Shared across the PRO RRT range

Parts commonly replaced

  • Flue pressure switch
  • Fan assembly
  • Printed Circuit Board

Related codes

A23

Your boiler has detected that the water inside is heating up too quickly or isn't circulating properly, so it has safely shut itself down to prevent damage.

High Engineer only £150-350 Shared across the PRO RRT range

Parts commonly replaced

  • Central heating pump
  • Flow sensor
  • Primary heat exchanger

Related codes

A24

Your boiler has detected that the main heat exchanger is getting too hot and has shut itself down to prevent damage.

High Engineer only £150-350 Shared across the PRO RRT range

Parts commonly replaced

  • NTC temperature sensor
  • Central heating pump
  • Primary heat exchanger

Related codes

A26

Your boiler has detected that the main heat exchanger is getting too hot or is failing to transfer heat effectively, so it has shut itself down to prevent internal damage.

High Engineer only £250-450 Shared across the PRO RRT range

Parts commonly replaced

  • Heat exchanger
  • Temperature sensors
  • Circulation pump

Related codes

A42

Your boiler has detected that the water temperature is rising too quickly or is not being correctly moderated, causing it to shut down for safety.

High Engineer only £150-250 Shared across the PRO RRT range

Parts commonly replaced

  • Central heating sensor
  • Return sensor
  • Main PCB

Related codes

A54

Your boiler's internal computer is experiencing a communication or hardware error, which has caused it to stop working for your safety.

High Engineer only £250-400 Shared across the PRO RRT range

Parts commonly replaced

  • Main PCB (AGC01)
  • Wiring harness

Related codes

A55

Your boiler's main control computer is experiencing a software or hardware error, which prevents it from operating correctly.

High Engineer only £250-450 Shared across the PRO RRT range

Parts commonly replaced

  • Main PCB (AGC01)

Related codes

A56

Your boiler is struggling to detect the flame needed to heat your home, likely because the sensor that monitors the combustion process is dirty, misaligned, or faulty.

High Engineer only £120-220 Shared across the PRO RRT range

Parts commonly replaced

  • Ignition/Ionisation Electrode
  • Ignition Lead

Related codes

A61

Your boiler's main internal computer is failing to communicate properly, which has forced the system to shut down to prevent further damage.

High Engineer only £250-450 Shared across the PRO RRT range

Parts commonly replaced

  • Main Control PCB

Related codes

A62

Your boiler has stopped working because its internal computer cannot send the necessary instructions to the gas supply mechanism.

High Engineer only £150-300 Shared across the PRO RRT range

Parts commonly replaced

  • Gas valve
  • Wiring harness
  • Main control PCB

Related codes

Showing 21–30 of 51
A63

Your boiler’s main computer chip is experiencing an internal error, preventing the system from monitoring or controlling your heating properly.

High Engineer only £250-400 Shared across the PRO RRT range

Parts commonly replaced

  • Main Control PCB

Related codes

A64

Your boiler has locked itself for safety because it was reset too many times while trying to clear a previous error.

High Engineer only £120-250 Shared across the PRO RRT range

Parts commonly replaced

  • Main circuit board (PCB)

Related codes

A68

Your boiler's internal computer is struggling to read its configuration settings, which has caused it to stop working for your safety.

High Engineer only £150-300 Shared across the PRO RRT range

Parts commonly replaced

  • BCC key
  • Main control board (PCB)

Related codes

d4

Your boiler is taking a short, temporary break to prevent itself from overheating while it manages the water temperature.

Low Engineer only Shared across the PRO RRT range
F07

Your boiler has detected an issue with the temperature sensors, meaning it cannot accurately measure how hot the water is and has stopped working as a safety precaution.

High Engineer only £120-220 Shared across the PRO RRT range

Parts commonly replaced

  • NTC temperature sensor
  • Wiring harness

Related codes

F08

Your boiler has detected that it is running too hot and has automatically shut itself down to prevent any damage or safety issues.

High Engineer only £120-250 Shared across the PRO RRT range

Parts commonly replaced

  • NTC Temperature Sensor
  • Primary Heat Exchanger
  • Pump (Circulator)

Related codes

F09

Your boiler has detected that the water inside it is getting too hot and has automatically shut down to prevent damage or potential overheating.

High Engineer only £120-250 Shared across the PRO RRT range

Parts commonly replaced

  • System pressure sensor
  • Central heating pump
  • NTC temperature sensor
  • Primary heat exchanger

Related codes

F10

Your boiler is struggling to detect the flow of water through the system, which means it has stopped providing heating and hot water to protect itself.

High Engineer only £150-250 Shared across the PRO RRT range

Parts commonly replaced

  • Flow sensor
  • Wiring loom

Related codes

F11

Your boiler is currently unable to read the water temperature accurately, so it has turned itself off for safety reasons until the issue is fixed.

High Engineer only £120-220 Shared across the PRO RRT range

Parts commonly replaced

  • Return temperature sensor
  • Wiring harness

Related codes

F12

Your boiler has lost the ability to accurately measure the temperature of your hot water supply, so it has stopped heating it to prevent overheating.

High Engineer only £120-180 Shared across the PRO RRT range

Parts commonly replaced

  • Domestic Hot Water (DHW) NTC Temperature Sensor

Related codes

Showing 31–40 of 51
F13

Your boiler has detected an issue with the sensor that monitors the temperature of the gases leaving your flue, causing it to shut down for safety reasons.

High Engineer only £120-220 Shared across the PRO RRT range

Parts commonly replaced

  • Flue gas sensor
  • Wiring harness

Related codes

F14

Your boiler has detected that the exhaust gases leaving the system are getting too hot, so it has shut itself down to prevent damage.

High Engineer only £150-300 Shared across the PRO RRT range

Parts commonly replaced

  • Primary heat exchanger
  • Flue gas temperature sensor
  • Central heating pump

Related codes

F15

Your boiler's computer has detected a configuration error and has safely shut itself down to prevent damage.

High Engineer only £150-300 Shared across the PRO RRT range

Parts commonly replaced

  • Main Control PCB
  • Configuration Key

Related codes

F20

Your boiler's internal computer is experiencing a software or configuration error that is preventing it from operating correctly.

High Engineer only £250-450 Shared across the PRO RRT range

Parts commonly replaced

  • Control Board (PCB)
  • Configuration card

Related codes

F21

The internal computer in your boiler has identified an error in its configuration settings, causing it to stop运行 safely.

High Engineer only £150-300 Shared across the PRO RRT range

Parts commonly replaced

  • Main Control PCB
  • Configuration card

Related codes

F34

Your boiler has detected that the electricity supply coming into your home is too weak to operate the unit safely.

High Engineer only £120-250 Shared across the PRO RRT range

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Power supply wiring connections

Related codes

F37

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

High DIY-safe £80-150 Shared across the PRO RRT range

What to check first

  1. Locate the filling loop, which is usually a metal braided hose underneath the boiler.
  2. Open the small valve or tap attached to the loop slowly, listening for water entering the system.
  3. Watch the pressure gauge on the front of the boiler until the needle reaches the green zone (typically 1.0 to 1.5 bar).
  4. Close the valve or tap tightly and check that the fault code has cleared.

Parts commonly replaced

  • Filling loop
  • Pressure sensor (transducer)
  • Expansion vessel

Related codes

F39

Your boiler is struggling to read the outdoor temperature, so it is defaulting to a standard internal setting until the sensor is fixed.

Low Engineer only £100-200 Shared across the PRO RRT range

Parts commonly replaced

  • External weather compensation sensor
  • Wiring harness

Related codes

F40

The boiler's internal computer has encountered a memory error or configuration mistake that prevents it from starting up correctly.

High Engineer only £150-300 Shared across the PRO RRT range

Parts commonly replaced

  • Control Board (PCB)
  • Configuration Plug

Related codes

F41

Your boiler has detected that water is heating up too quickly compared to the sensors' expectations, causing it to shut down to prevent damage.

High Engineer only £120-250 Shared across the PRO RRT range

Parts commonly replaced

  • NTC sensor
  • Circulation pump
  • Heat exchanger

Related codes

Showing 41–50 of 51
F42

Your boiler has detected an inconsistent temperature reading between its internal sensors, which has caused it to stop working as a safety precaution to prevent overheating.

High Engineer only £150-250 Shared across the PRO RRT range

Parts commonly replaced

  • Dual NTC temperature sensor
  • Wiring harness
  • Printed Circuit Board (PCB)

Related codes

F43

Your boiler has detected that the heat exchanger is getting too hot, likely due to a lack of water flow, triggered to prevent potential damage to the internal components.

High Engineer only £150-350 Shared across the PRO RRT range

Parts commonly replaced

  • Central heating pump
  • System filter
  • Flow sensor
  • Primary heat exchanger

Related codes

F47

Your boiler's computer system has detected an error in its internal settings, causing it to stop operating to prevent further issues.

High Engineer only £150-300 Shared across the PRO RRT range

Parts commonly replaced

  • Main printed circuit board (PCB)
  • Control board

Related codes

F50

Your boiler's internal computer is experiencing a software or configuration error that is preventing it from operating correctly.

High Engineer only £250-450 Shared across the PRO RRT range

Parts commonly replaced

  • Main Control PCB
  • Configuration Key

Related codes

F51

Your boiler's internal computer has encountered a configuration error and cannot communicate correctly with the heating system.

High Engineer only £150-300 Shared across the PRO RRT range

Parts commonly replaced

  • Control PCB
  • Display interface board

Related codes

F53

Your boiler’s internal computer has encountered a memory or configuration error, meaning it has forgotten how to safely manage its own heating process.

High Engineer only £250-450 Shared across the PRO RRT range

Parts commonly replaced

  • Main PCB
  • Configuration EEPROM
F56

Your boiler is struggling to detect the flame needed to heat your water and home, likely because the sensor that monitors the burn is worn out or out of place.

High Engineer only £120-220 Shared across the PRO RRT range

Parts commonly replaced

  • Ignition/Detection Electrode
  • Ignition Lead

Related codes

F61

Your boiler's internal electronic control center is experiencing a critical communication error and cannot safely operate the heating system.

High Engineer only £250-450 Shared across the PRO RRT range

Parts commonly replaced

  • Main PCB (AGC01)
  • Wiring harness
F66

Your boiler's internal computer has failed to start up correctly, which means it cannot operate your heating or hot water systèmes.

High Engineer only £150-300 Shared across the PRO RRT range

Parts commonly replaced

  • Main control board (PCB)
  • Wiring harness

Related codes

F67

Your boiler is currently in a setup or diagnostic mode because a programming key has been left plugged into its internal control board.

Low Engineer only £80-120 Shared across the PRO RRT range

Parts commonly replaced

  • BCC Service Key

Related codes

Showing 51–51 of 51
F68

Your boiler's internal computer is failing to communicate correctly with its memory chip, which prevents the system from starting up safely.

High Engineer only £150-300 Shared across the PRO RRT range

Parts commonly replaced

  • BCC (Boiler Control Configuration) key
  • Main PCB

Related codes

3 operating states & engineer diagnostics

Not faults — these are normal operating states. Tap to expand.

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