BoilerFaultCodes 4 (Flashing)
Your boiler is currently in standby mode and is working exactly as it should while waiting for a request for heat.
Ferroli Falcon Fault codes & diagnostics
27 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Combi Natural Gas 24-30 kW 2007-2012 Discontinued
Replaced by: Ferroli Modena
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. 18 High
1 Medium
8 Low
Just want the most common Ferroli Falcon faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes
All 27 documented codes
Tap any card for details
LED / flash-pattern codes
5 (Flashing) Your boiler has stopped working because the water pressure inside the heating system has dropped too low to operate safely.
Your boiler has stopped working because the water pressure inside the heating system has dropped too low to operate safely.
What to check first
- Locate the filling loop (a flexible silver hose) underneath the boiler.
- Open the small valve(s) on the loop to allow water into the system.
- Monitor the pressure gauge on the boiler until it reaches the green zone (typically 1.0 to 1.5 bar).
- Close the valve(s) tightly to stop the flow.
Parts commonly replaced
- Pressure relief valve
- Filling loop
LED 4 Flashing (DHW Mode) Your boiler is failing to detect when you turn on the hot tap, meaning it cannot start the burner to heat your water.
Your boiler is failing to detect when you turn on the hot tap, meaning it cannot start the burner to heat your water.
Parts commonly replaced
- DHW Flow Sensor
- Hall Effect Sensor
Related codes
LED 5 Flashing Your boiler's electronic control centre is failing to communicate properly, which has caused the system to shut down for safety.
Your boiler's electronic control centre is failing to communicate properly, which has caused the system to shut down for safety.
Parts commonly replaced
- Main printed circuit board (PCB)
- 2A internal fuse
- Wiring loom
LED4 (Flashing) Your boiler is currently in standby mode and is working exactly as it should, waiting for a signal to provide heat or hot water.
Your boiler is currently in standby mode and is working exactly as it should, waiting for a signal to provide heat or hot water.
What to check first
- Check your room thermostat is set to a higher temperature than the current room temperature
- Ensure your heating timer or programmer is currently in an 'on' period
- Verify that the boiler's own selector switch is set to the heating or hot water mode
LED4 flashing Your boiler is struggling to detect water moving through the system, which prevents it from safely firing up to heat your home or provide hot water.
Your boiler is struggling to detect water moving through the system, which prevents it from safely firing up to heat your home or provide hot water.
Parts commonly replaced
- Flow sensor
- Circulation pump
- PCB main board
LED5 (Flashing) Your boiler has stopped working because the water pressure inside the heating system has dropped too low.
Your boiler has stopped working because the water pressure inside the heating system has dropped too low.
What to check first
- Locate the filling loop, which is a silver braided hose with one or two valves connecting your boiler to the mains water supply.
- Open the valve(s) 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.
- Turn off the valve(s) completely and ensure they are tightened to prevent future pressure loss.
Parts commonly replaced
- Filling loop
- Pressure relief valve
- Pressure sensor
Digital codes
4 (Permanent)
Your boiler is currently indicating that it is actively running your central heating system.
5 (Permanent) Your boiler is operating normally and is currently receiving power from the electricity supply.
Your boiler is operating normally and is currently receiving power from the electricity supply.
What to check first
- No action is required as this is not an error code.
- If your boiler is not producing heat or hot water, check that your thermostat and programmer are set to 'ON'.
Boiler lock out Your boiler has stopped working as a safety precaution and needs to be manually reset to try and restart the system.
Your boiler has stopped working as a safety precaution and needs to be manually reset to try and restart the system.
What to check first
- Locate the on/off/reset switch on the front control panel.
- Turn the switch to the 'reset' position and hold it briefly.
- Return the switch to the 'on' position and wait to see if the burner ignites.
Parts commonly replaced
- Ignition electrode
- Flame rectification probe
- Printed circuit board (PCB)
Showing 11–20 of 27
Bottom red light Your boiler has stopped working because the water pressure inside the heating system has dropped too low.
Your boiler has stopped working because the water pressure inside the heating system has dropped too low.
What to check first
- Locate the filling loop, which is usually a flexible silver hose or two valves sitting underneath the boiler.
- Open the valves slowly to allow water into the system until the pressure gauge needle reaches the 1 to 1.5 bar mark.
- Close both valves tightly to stop the flow of water and check if the red light resets.
Parts commonly replaced
- Filling loop
- Pressure gauge
- Pressure relief valve
Heating demand light OFF Your boiler is currently idle because it is not receiving a signal from your thermostat or timer to turn the heating on.
Your boiler is currently idle because it is not receiving a signal from your thermostat or timer to turn the heating on.
What to check first
- Check your room thermostat is set to a temperature higher than the current room temperature
- Ensure your heating timer or programme clock is correctly set to an 'ON' period
- Replace the batteries in your wireless room thermostat if applicable
Parts commonly replaced
- Room thermostat
- Programmer/Timer
- External wiring
Heating demand light ON Your boiler is confused because a sensor that measures the temperature of your heating water has stopped sending the correct signal, so it has turned off the heating to stay safe.
Your boiler is confused because a sensor that measures the temperature of your heating water has stopped sending the correct signal, so it has turned off the heating to stay safe.
Parts commonly replaced
- Central Heating NTC Sensor
- Wiring harness
LED 3 OFF (DHW Mode) Your boiler has lost the ability to measure the temperature of the water used for your taps and shower, so it cannot produce hot water.
Your boiler has lost the ability to measure the temperature of the water used for your taps and shower, so it cannot produce hot water.
Parts commonly replaced
- DHW NTC sensor
- Wiring harness
LED 4
Your boiler is currently in a brief, normal rest period designed to protect the heating system, and it should restart automatically within three minutes.
LED 5 ON Your boiler has stopped working because the water pressure inside the system has dropped too low to operate safely.
Your boiler has stopped working because the water pressure inside the system has dropped too low to operate safely.
What to check first
- Locate the external filling loop, which is a silver braided hose with one or two valves connecting your boiler to the mains water supply.
- Open the valve(s) slowly to allow water into the system until the pressure gauge on the front of the boiler reads between 1 and 1.5 bar.
- Fully close the valve(s) and ensure no water is dripping from the connection.
Parts commonly replaced
- Filling loop
- Pressure gauge
LED 6 Your boiler has detected that there is not enough water inside the system to operate safely, so it has turned itself off to prevent damage.
Your boiler has detected that there is not enough water inside the system to operate safely, so it has turned itself off to prevent damage.
What to check first
- Locate the filling loop, which is usually a flexible silver hose connected to two valves under the boiler.
- 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.
- Close the valves firmly and check for any leaks around the connection points.
Parts commonly replaced
- Pressure relief valve
- Pressure sensor
- Expansion vessel
LED1 Your boiler has failed to ignite, meaning it is currently unable to produce heat or hot water because it cannot successfully light its internal burner.
Your boiler has failed to ignite, meaning it is currently unable to produce heat or hot water because it cannot successfully light its internal burner.
Parts commonly replaced
- Ignition electrode
- Gas valve
- Control board
LED2 Your boiler has detected a safety concern or overheating issue and has intentionally shut itself down to prevent damage.
Your boiler has detected a safety concern or overheating issue and has intentionally shut itself down to prevent damage.
Parts commonly replaced
- Safety limit thermostat
- Overheat sensor
- Printed Circuit Board (PCB)
Related codes
LED3
Your boiler is operating normally and is currently receiving instructions from your thermostat or timer to provide heating.
Showing 21–27 of 27
LED4 (Permanent) Your boiler is correctly operating in heating mode, and the light indicates that your central heating system is currently active.
Your boiler is correctly operating in heating mode, and the light indicates that your central heating system is currently active.
What to check first
- Check your room thermostat or boiler timer settings
- Turn down the temperature dial on your thermostat to see if the light turns off
- If you want the heating off, ensure your wall controller is set to off or standby
LED5 (Permanent) Your boiler is failing to detect the incoming electrical power required to operate safely.
Your boiler is failing to detect the incoming electrical power required to operate safely.
Parts commonly replaced
- Printed Circuit Board (PCB)
- Wiring harness
- External spur fuse
Related codes
Low water pressure light ON Your boiler has stopped working because the water pressure inside the system has dropped too low, which is causing it to lock itself to prevent damage.
Your boiler has stopped working because the water pressure inside the system has dropped too low, which is causing it to lock itself to prevent damage.
What to check first
- Locate the filling loop (a silver flexi-hose) underneath your boiler.
- Open the valves attached to the loop until you hear water flowing.
- Watch the pressure gauge on the front of the boiler until the needle reaches between 1 and 1.5 bar.
- Firmly close the valves to stop the flow.
Parts commonly replaced
- Pressure relief valve
- Pressure sensor switch
- Expansion vessel
Red light (egg timer symbol)
Your boiler is perfectly fine; it is simply taking a short three-minute pause to protect itself from excessive cycling before it switches the heating back on.
Red lockout light Your boiler has detected a problem and safely shut itself down to prevent damage, meaning you currently have no heating or hot water.
Your boiler has detected a problem and safely shut itself down to prevent damage, meaning you currently have no heating or hot water.
Parts commonly replaced
- Ignition electrode
- Flame sensor
- Printed Circuit Board (PCB)
- Gas valve
Tap symbol light OFF Your boiler is failing to detect that you have turned on a hot tap, so it is not firing up to heat your water.
Your boiler is failing to detect that you have turned on a hot tap, so it is not firing up to heat your water.
Parts commonly replaced
- DHW Flow meter
- Flow Hall effect sensor
Tap symbol light ON Your boiler is struggling to detect the temperature of the water for your taps, which means it will likely stop providing hot water until the faulty sensor is replaced.
Your boiler is struggling to detect the temperature of the water for your taps, which means it will likely stop providing hot water until the faulty sensor is replaced.
Parts commonly replaced
- DHW NTC thermistor
- Wiring harness