Ferroli Modena HE Fault codes & diagnostics

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

SystemCombi Natural GasLPG 18-32 kW 2012-2016 Discontinued
GC Numbers 41-583-2041-583-2141-583-22

Replaced by: Bluehelix Tech RRT

This boiler uses LED flash patterns

Count the flashes in one repeating group before the pause. That number is your fault code. Do not reset until you have noted it. How to read fault codes →

Severity at a glance

Each cell = one fault code. Hover to identify.
40 High 2 Medium 11 Low
Just want the most common Ferroli Modena HE faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes

All 53 documented codes

Tap any card for details

LED / flash-pattern codes
4 (Flashing Light)

Your boiler is working exactly as it should and is currently waiting for a command from your room thermostat or timer to start heating.

Low DIY-safe

What to check first

  1. Check your room thermostat is turned up to a temperature higher than the current room temperature.
  2. Ensure your heating timer or programmer is set to the 'On' or 'Timed' position.
  3. Verify that the boiler's own mode selector is set to both heating and hot water if required.
Full explanation for 4 (Flashing Light)
5 (Flashing Light)

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

High DIY-safe £80-150

What to check first

  1. Locate the filling loop, which is usually a flexible silver hose with one or two valves typically found underneath your boiler.
  2. Open the valves slowly to allow water into the system until the pressure gauge on the front of the boiler reads between 1.0 and 1.5 bar.
  3. Close both valves tightly to prevent over-pressurisation and check your radiators for any visible leaks.

Parts commonly replaced

  • Filling loop
  • Pressure relief valve
  • Pressure gauge

Related codes

Full explanation for 5 (Flashing Light)
LED 4 (Flashing)

Your boiler is struggling to accurately detect the water temperature or flow, so it has stopped working to prevent potential overheating.

High Engineer only £120-220

Parts commonly replaced

  • Central Heating NTC Sensor
  • Domestic Hot Water NTC Sensor
  • Flow Switch

Related codes

Full explanation for LED 4 (Flashing)
LED 5 (Flashing light)

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

High DIY-safe £0-£120

What to check first

  1. Locate the external filling loop (a flexible silver hose beneath the boiler connecting two pipes)
  2. Open the valves at both ends of the hose to allow water into the system
  3. Watch the pressure gauge on the front of the boiler until the needle reaches the green zone (typically 1 to 1.5 bar)
  4. Close both valves tightly and remove the hose if required by your specific model instructions

Parts commonly replaced

  • Filling loop
  • Pressure relief valve
  • Pressure sensor

Related codes

Full explanation for LED 5 (Flashing light)
LED 5 (Flashing)

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

High DIY-safe £80-150

What to check first

  1. Locate the external filling loop, which is a flexible silver hose connected to your boiler pipes.
  2. Open the valves at both ends of the hose to allow water into the system until the pressure gauge reads between 1 and 1.5 bar.
  3. Close both valves tightly and ensure the hose is disconnected or the valves are fully shut to prevent accidental over-pressurising.

Parts commonly replaced

  • Filling loop
  • Pressure relief valve
  • Pressure gauge

Related codes

Full explanation for LED 5 (Flashing)
LED5 flashing

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

High DIY-safe £80-150

What to check first

  1. Locate the external filling loop (a flexible silver hose beneath the boiler connecting two pipes).
  2. Slowly open the valves on both ends of the hose until you hear water flowing.
  3. Watch the pressure gauge on the front of the boiler until the needle reaches between 1 and 1.5 bar, then turn both valves off tightly.

Parts commonly replaced

  • Filling loop
  • Pressure relief valve
  • Pressure gauge

Related codes

Full explanation for LED5 flashing
Digital codes
5 (Permanent Light)

Your boiler is operating normally and is receiving mains electricity as expected.

Low DIY-safe

What to check first

  1. No action required as this indicates normal system status.
Full explanation for 5 (Permanent Light)
A01

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

High DIY-safe £120-£350

What to check first

  1. Check if other gas appliances in your home, like a hob, are working to ensure gas is reaching the property.
  2. Verify that your gas prepaid meter has credit, if applicable.
  3. Press the 'Reset' button on the boiler control panel once to see if the system restarts.

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • PCB (Printed Circuit Board)

Related codes

Full explanation for A01
Showing 11–20 of 53
A02

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.

High Engineer only £120-£350

Parts commonly replaced

  • Ionisation electrode
  • Ignition electrode
  • Main PCB

Related codes

Full explanation for A02
A03

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.

High DIY-safe £120-300

What to check first

  1. Check that your radiator valves and isolation valves are fully open
  2. Ensure your system pressure is topped up to between 1 and 1.5 bar
  3. Press the Reset button on the control panel to see if the fault clears

Parts commonly replaced

  • Circulation pump
  • Overheat thermostat
  • Flow temperature sensor (NTC)

Related codes

Full explanation for A03
A04

Your boiler has shut down because it detected a repeat issue with its exhaust system three times in one day.

High Engineer only £120-350

Parts commonly replaced

  • Pressure switch
  • Flue fan
  • Venturi tube

Related codes

Full explanation for A04
A05

Your boiler has stopped working because its internal fan, which safely exhausts gases, is not communicating correctly with the main control board.

High Engineer only £180-£350

Parts commonly replaced

  • Fan assembly
  • Wiring harness
  • Printed Circuit Board (PCB)

Related codes

Full explanation for A05
A06

Your boiler is failing to detect a flame after it tries to start up, meaning it cannot provide heating or hot water.

High Engineer only £120-280

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • Detection electrode
  • PCB

Related codes

Full explanation for A06
A41

Your boiler has lost communication with the internal sensor that monitors water temperature, meaning it cannot safely heat your home or water.

High Engineer only £120-190

Parts commonly replaced

  • Flow temperature NTC sensor
  • Wiring harness connector

Related codes

Full explanation for A41
A42

The boiler's internal thermometer is sending an incorrect signal to the control board, preventing the system from heating your water correctly.

High Engineer only £120-190

Parts commonly replaced

  • Flow temperature NTC sensor
  • Sensor wiring harness

Related codes

Full explanation for A42
A61

Your boiler's main internal computer has developed a technical fault and can no longer communicate with the rest of the system.

High Engineer only £250-£450

Parts commonly replaced

  • Main PCB (ABM03B Controller)
  • Wiring Harness

Related codes

Full explanation for A61
A62

Your boiler's computer cannot talk to the gas valve, meaning it cannot light the flame to provide heating or hot water.

High Engineer only £180-£350

Parts commonly replaced

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

Related codes

Full explanation for A62
A63

Your boiler's main internal computer has developed a technical fault and can no longer control the heating system safely.

High Engineer only £250-£450

Parts commonly replaced

  • Main PCB (ABM03B Control Board)
  • Wiring Harness

Related codes

Full explanation for A63
Showing 21–30 of 53
A64

Your boiler's main internal computer has developed a technical fault and can no longer control the heating system safely.

High Engineer only £250-£450

Parts commonly replaced

  • Main PCB (ABM03B Control Board)
  • Wiring Harness

Related codes

Full explanation for A64
E01

Your boiler has failed to start because it cannot detect a flame, meaning you currently have no heating or hot water.

High Engineer only £120-250

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • Printed Circuit Board

Related codes

Full explanation for E01
E02

Your boiler has switched itself off because it has become dangerously hot inside, suggesting a blockage or a failure in the system's ability to circulate water.

High Engineer only £150-300

Parts commonly replaced

  • Pump
  • System filter
  • Heat exchanger
  • NTC thermistor

Related codes

Full explanation for E02
E03

Your boiler has detected an issue with its internal airflow system, which is preventing it from safely starting up the burner.

High Engineer only £120-250

Parts commonly replaced

  • Air pressure switch
  • Venturi nozzle
  • Flue fan

Related codes

Full explanation for E03
E04

Your boiler has detected that the water inside the heating system has become too hot and has automatically shut down to prevent damage.

High Engineer only £120-250

Parts commonly replaced

  • Flow temperature sensor
  • Central heating pump
  • System filter blockage removal

Related codes

Full explanation for E04
E05

Your boiler has lost its ability to measure the temperature of the water keeping your home warm, so it has safely shut down to prevent overheating.

High Engineer only £120-200

Parts commonly replaced

  • Central heating flow NTC sensor
  • Wiring harness

Related codes

Full explanation for E05
E06

Your boiler is currently unable to properly detect the temperature of your hot water, which means it has stopped heating it to prevent the system from overheating.

High Engineer only £120-200

Parts commonly replaced

  • DHW NTC thermistor sensor
  • Wiring harness

Related codes

Full explanation for E06
E31

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

High DIY-safe £80-120

What to check first

  1. Locate the external filling loop, which is a flexible silver hose connected to two valves under the boiler.
  2. Gradually open the valves to let water into the system until the pressure gauge on the front reads between 1.0 and 1.5 bar.
  3. Close both valves firmly and check that the error code has cleared.

Parts commonly replaced

  • Filling loop
  • Pressure gauge
  • Pressure relief valve

Related codes

Full explanation for E31
F07

Your boiler has detected that the exhaust gases are getting too hot, which has caused the system to shut down for safety.

High Engineer only £120-£450

Parts commonly replaced

  • Heat exchanger
  • Flue gas probe
  • Main heat exchanger descaling

Related codes

Full explanation for F07
F10

Your boiler's internal sensor that monitors the temperature of water leaving the unit has stopped working correctly, and the system has shut down to prevent overheating.

High Engineer only £100-180

Parts commonly replaced

  • Central Heating Flow Temperature Sensor (NTC)
  • Wiring harness

Related codes

Full explanation for F10
Showing 31–40 of 53
F11

Your boiler's internal sensor that monitors the temperature of the water returning to the unit has stopped communicating correctly, causing the system to shutdown for safety.

High Engineer only £90-160

Parts commonly replaced

  • Return NTC Temperature Sensor
  • Wiring harness
  • Electronic Control Board (PCB)

Related codes

Full explanation for F11
F12

Your boiler has lost its connection to the sensor that monitors your hot water temperature, which means you will likely experience cold showers until it is fixed.

Medium Engineer only £90-160

Parts commonly replaced

  • DHW Temperature Sensor (NTC)
  • Wiring harness connector

Related codes

Full explanation for F12
F13

Your boiler's internal temperature sensor has stopped sending the correct information to the control board, preventing the system from operating safely.

High Engineer only £90-160

Parts commonly replaced

  • Heat exchanger NTC sensor
  • Wiring harness

Related codes

Full explanation for F13
F14

Your boiler has stopped working because it cannot correctly measure the temperature of the water leaving the unit.

High Engineer only £90-160

Parts commonly replaced

  • Flow NTC temperature sensor
  • Wiring harness

Related codes

Full explanation for F14
F15

Your boiler has stopped working because it cannot properly control the fan that removes waste gases from the system.

High Engineer only £180-450

Parts commonly replaced

  • Extractor Fan
  • Fan Wiring Harness
  • Main Control Board (PCB)

Related codes

Full explanation for F15
F34

Your boiler is not receiving enough electricity from the mains supply to operate its electronic components safely.

High Engineer only £100-350

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • External Electrical Supply Wiring

Related codes

Full explanation for F34
F35

Your boiler has detected an issue with the quality of the electricity coming into your home, meaning the power supply is not stable enough for it to operate safely.

Medium Engineer only £100-350

Parts commonly replaced

  • PCB (Main Control Board)
  • Surge Protector

Related codes

Full explanation for F35
F37

Your boiler has stopped working because the water pressure inside the system has dropped too low to operate safely.

High DIY-safe £0-160

What to check first

  1. Locate the filling loop (usually a silver flexible hose) underneath or near the boiler.
  2. Slowly open the one or two small valves on the filling loop to allow water into the system.
  3. Watch the pressure gauge and close the valves tightly once the needle reaches between 1.0 and 1.5 bar.

Parts commonly replaced

  • Water pressure sensor
  • Filling loop
  • Expansion vessel

Related codes

Full explanation for F37
F39

Your boiler has sensed it is getting too hot too quickly and has shut down to protect its internal parts from damage.

High DIY-safe £90-180

What to check first

  1. Check that your radiator valves are open and not turned to the off position.
  2. Ensure the boiler pressure is between 1.0 and 1.5 bar on the pressure gauge.
  3. Try bleeding your radiators to remove any trapped air that might be blocking water flow.

Parts commonly replaced

  • Temperature Sensor (NTC thermistor)
  • Circulation Pump
  • Main Heat Exchanger (if scaled)

Related codes

Full explanation for F39
F43

Your boiler has stopped working because water is not moving through it properly or there is trapped air causing it to overheat.

High DIY-safe £100-£350

What to check first

  1. Check that your system pressure is between 1 and 1.5 bar on the pressure gauge
  2. Bleed all radiators in your home to remove trapped air
  3. Ensure all radiator valves and external isolation valves are fully open

Parts commonly replaced

  • Circulation Pump
  • Automatic Air Vent
  • Main Heat Exchanger

Related codes

Full explanation for F43
Showing 41–50 of 53
F52

Your boiler has detected a problem with the internal sensor that monitors water temperature or flow, meaning it cannot safely regulate how much it heats the water.

High Engineer only £120-£200

Parts commonly replaced

  • Flow NTC sensor
  • Wiring harness

Related codes

Full explanation for F52
F66

Your boiler's main internal computer has developed a technical fault and can no longer control the heating system safely.

High Engineer only £250-£450

Parts commonly replaced

  • Main PCB (ABM03B Control Board)
  • Wiring Harness

Related codes

Full explanation for F66
LED 2

Your boiler has stopped working because it failed to start up safely or lost its flame during operation.

High Engineer only £150-350

Parts commonly replaced

  • Air pressure switch
  • Ignition electrode
  • Flame sensing probe
  • Printed Circuit Board
Full explanation for LED 2
LED 5 (Permanent)

Your boiler is receiving power and is currently in standby mode, meaning it is ready to operate as normal.

Low DIY-safe

What to check first

  1. Check your thermostat or programmer settings to ensure there is a demand for heating or hot water
  2. Ensure the boiler operating mode is set to 'Summer' or 'Winter' and not 'Off'
  3. Check that the isolation switch near the boiler is turned on
Full explanation for LED 5 (Permanent)
LED2 on

Your boiler has detected a safety issue or failed to start, so it has automatically turned itself off to prevent any potential danger.

High Engineer only £120-250

Parts commonly replaced

  • Ignition electrode
  • Safety thermostat
  • Fan assembly
  • Control PCB

Related codes

Full explanation for LED2 on
Showing 51–53 of 53
LED5 on

Your boiler is receiving power, but it is not currently operating because it has detected an internal error that requires attention.

High Engineer only £120-250

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Wiring harness
  • Control panel

Related codes

Full explanation for LED5 on
Red lockout light

Your boiler has detected an internal safety issue and has shut itself down to prevent damage, meaning you currently have no heating or hot water.

High Engineer only £120-250

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • PCB
  • Flame rectification probe

Related codes

Full explanation for Red lockout light