BoilerFaultCodes 00:1
Your boiler is currently operating on its basic factory configuration for a simple heating system and is not indicating a fault.
Viessmann Vitodens 200-W Fault codes & diagnostics
211 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
CombiSystem Natural GasLPG 11-60 kW 2011-present
GC Numbers 47-819-2147-819-2247-819-2347-819-2747-819-2847-819-2947-819-3047-819-3147-819-3247-819-3347-819-3447-819-5347-819-5447-819-5547-819-56
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Severity at a glance
Each cell = one fault code. Hover to identify. 83 High
53 Medium
75 Low
Just want the most common Viessmann Vitodens 200-W faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes
All 211 documented codes
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00:2
This code is simply an information display showing your boiler's current setup configuration, rather than an error or a heating problem.
00:3
Your boiler is correctly operating in a specific configuration that manages one heating zone without providing domestic hot water.
00:4
This code is not actually a fault, but a status indicator confirming your boiler is configured to control both your radiators and your hot water tank separately.
00:5
Your boiler is correctly configured for your specific heating setup and this code is simply informing you how your system is currently set up to operate.
00:6
Your boiler is correctly configured for your specific home heating setup, and this code is simply an information status indicating how your system is set up to manage your radiators and hot water.
0A Your boiler has detected an issue with the gas pressure or a component failure and has shut down as a safety precaution.
Your boiler has detected an issue with the gas pressure or a component failure and has shut down as a safety precaution.
Parts commonly replaced
- Gas pressure switch
- Ignition electrodes
- Gas valve
- Burner control unit
Related codes
0C Your boiler has shut down because the electrical power coming into it is too weak or unstable to run safely.
Your boiler has shut down because the electrical power coming into it is too weak or unstable to run safely.
Parts commonly replaced
- Electronic control unit (PCB)
- Voltage regulator
Related codes
0D Your boiler has detected an internal communication error and has shut itself down as a safety precaution.
Your boiler has detected an internal communication error and has shut itself down as a safety precaution.
Parts commonly replaced
- Burner Control Unit
- Ignition Lead
- Main PCB
Related codes
0F Your boiler is simply reminding you that it is due for its regular annual service and there is no actual fault with the system.
Your boiler is simply reminding you that it is due for its regular annual service and there is no actual fault with the system.
Parts commonly replaced
- Service kit (gaskets and electrodes)
Related codes
Showing 11–20 of 211
1A Your boiler has shut down because it is struggling to discharge exhaust fumes safely or is detecting a significant lack of air flow.
Your boiler has shut down because it is struggling to discharge exhaust fumes safely or is detecting a significant lack of air flow.
Parts commonly replaced
- Flue gas sensor
- Heat exchanger (cleaning)
- Ventilation fan
- Condensate trap
Related codes
1B Your boiler has shut down because it is struggling to discharge exhaust fumes safely or is detecting a significant lack of air flow.
Your boiler has shut down because it is struggling to discharge exhaust fumes safely or is detecting a significant lack of air flow.
Parts commonly replaced
- Flue gas sensor
- Heat exchanger (cleaning)
- Ventilation fan
- Condensate trap
Related codes
1E:0
Your boiler is currently set up to run on natural gas and is operating normally.
1E:1
Your boiler is correctly identifying that it is running on LPG rather than mains natural gas, confirming that the initial installation settings match your fuel supply.
1F Your boiler has stopped working because the burner isn't lighting correctly, likely due to a problem with the internal airflow or the ignition system.
Your boiler has stopped working because the burner isn't lighting correctly, likely due to a problem with the internal airflow or the ignition system.
Parts commonly replaced
- Ionisation electrode
- Ignition lead
- Gas valve
- Fan assembly
Related codes
02 Your boiler has shut itself down as a safety precaution because it has detected an overheating issue within the system.
Your boiler has shut itself down as a safety precaution because it has detected an overheating issue within the system.
Parts commonly replaced
- Circulation pump
- Overheat thermostat
- Heat exchanger (cleaning/flush)
Related codes
2E:0 Your boiler is struggling to communicate with an optional add-on controller or sensor that it thinks should be connected.
Your boiler is struggling to communicate with an optional add-on controller or sensor that it thinks should be connected.
Parts commonly replaced
- External extension module
- Communication cable
- PCB
2F:0 Your boiler is currently stuck in or has failed to complete its internal air-purging process, preventing it from firing up normally.
Your boiler is currently stuck in or has failed to complete its internal air-purging process, preventing it from firing up normally.
Parts commonly replaced
- Control board/PCB
- Wiring harness
Related codes
2F:1 Your boiler is currently running a brief automated cycle to clear air from the system, which is a normal process.
Your boiler is currently running a brief automated cycle to clear air from the system, which is a normal process.
Related codes
2F:2 Your boiler is currently running an automated process to clear air out of the system after it was recently refilled or serviced.
Your boiler is currently running an automated process to clear air out of the system after it was recently refilled or serviced.
What to check first
- Wait 20 minutes for the automated program to finish.
- If the code persists, restart the boiler using the power switch.
- Ensure your system pressure is set correctly between 1.0 and 1.5 bar.
Related codes
Showing 21–30 of 211
04 Your boiler has detected a sequence of ignition or flame detection errors and has shut itself down for safety.
Your boiler has detected a sequence of ignition or flame detection errors and has shut itself down for safety.
Parts commonly replaced
- Ignition Electrode
- Ionisation Electrode
- Gas Valve
- Electronic Control Unit (PCB)
Related codes
05 Your boiler has detected a sequence of ignition or flame detection errors and has shut itself down for safety.
Your boiler has detected a sequence of ignition or flame detection errors and has shut itself down for safety.
Parts commonly replaced
- Ignition Electrode
- Ionisation Electrode
- Gas Valve
- Electronic Control Unit (PCB)
Related codes
5B:0 Your boiler has detected that the hot water cylinder is connected directly to the unit, but there is likely a communication error or a faulty sensor preventing it from heating your water correctly.
Your boiler has detected that the hot water cylinder is connected directly to the unit, but there is likely a communication error or a faulty sensor preventing it from heating your water correctly.
Parts commonly replaced
- DHW cylinder temperature sensor
- Connection cable harness
- NTC thermistor
Related codes
5B:1 Your boiler is confused about where your hot water tank is located within the system pipework, often due to a setup error or a sensor problem.
Your boiler is confused about where your hot water tank is located within the system pipework, often due to a setup error or a sensor problem.
Parts commonly replaced
- NTC Temperature Sensor
- Cylinder Demand Sensor
Related codes
06 Your boiler has detected a sequence of ignition or flame detection errors and has shut itself down for safety.
Your boiler has detected a sequence of ignition or flame detection errors and has shut itself down for safety.
Parts commonly replaced
- Ignition Electrode
- Ionisation Electrode
- Gas Valve
- Electronic Control Unit (PCB)
Related codes
06:... Your boiler has detected that the water inside the system has become dangerously hot and has shut itself down to prevent damage.
Your boiler has detected that the water inside the system has become dangerously hot and has shut itself down to prevent damage.
Parts commonly replaced
- Temperature sensor (NTC)
- Pump
- PCB
- Heat exchanger
Related codes
6C:0 to 6C:100 Your boiler's internal pump or fan is reporting an incorrect speed setting, which is usually a technical communication error between the internal computer and the parts that move water or air.
Your boiler's internal pump or fan is reporting an incorrect speed setting, which is usually a technical communication error between the internal computer and the parts that move water or air.
Parts commonly replaced
- Main PCB
- Circulation Pump
- Fan Assembly
Related codes
6C:100 Your boiler's internal pump for hot water is stuck running at full speed, which usually means there is a communication error or a part is beginning to fail.
Your boiler's internal pump for hot water is stuck running at full speed, which usually means there is a communication error or a part is beginning to fail.
Parts commonly replaced
- Internal DHW loading pump
- Pump cable harness
- Main PCB
6F:0 to 6F:100 Your boiler is providing an advisory notification about how much power it is using to heat your hot water, rather than indicating a mechanical breakdown.
Your boiler is providing an advisory notification about how much power it is using to heat your hot water, rather than indicating a mechanical breakdown.
Parts commonly replaced
- Boiler Control Unit
- NTC Sensor
Related codes
6F:100 Your boiler is telling you that it has defaulted to its maximum power setting for heating your hot water because it has encountered a configuration memory error.
Your boiler is telling you that it has defaulted to its maximum power setting for heating your hot water because it has encountered a configuration memory error.
Parts commonly replaced
- Boiler Coding Card
- Control Circuit Board (PCB)
Related codes
Showing 31–40 of 211
07 Your boiler has detected a sequence error or a flame signal where there shouldn't be one, causing the burner to shut down completely for safety.
Your boiler has detected a sequence error or a flame signal where there shouldn't be one, causing the burner to shut down completely for safety.
Parts commonly replaced
- Ionisation electrode
- Ignition cable
- Burner control unit (PCB)
Related codes
7b:0 Your boiler is having a communication problem regarding the time settings between its internal control parts.
Your boiler is having a communication problem regarding the time settings between its internal control parts.
What to check first
- Turn the boiler power off at the fused spur switch.
- Wait for 30 seconds.
- Turn the power back on and check if the date and time settings are correct on the display.
Parts commonly replaced
- None
- LON communication module
Related codes
7b:1 Your boiler is having difficulty communicating the correct time to other parts of the heating system or external controls.
Your boiler is having difficulty communicating the correct time to other parts of the heating system or external controls.
What to check first
- Check the time and date settings on the boiler control panel
- Ensure the correct time is set and save the settings
- Turn the boiler power off and back on to refresh the signal
Parts commonly replaced
- None (Software/Configuration issue)
- LON communication module
Related codes
7E:0 Your boiler has been incorrectly set to a multi-boiler configuration even though it is operating as a single unit.
Your boiler has been incorrectly set to a multi-boiler configuration even though it is operating as a single unit.
Parts commonly replaced
- Main PCB (Configuration only)
Related codes
7E:1 Your boiler system is communicating with multiple other boilers through a shared exhaust pipe, and it has detected a technical configuration error in that connection.
Your boiler system is communicating with multiple other boilers through a shared exhaust pipe, and it has detected a technical configuration error in that connection.
Parts commonly replaced
- Communication Module
- Flue Gas Sensor
7F:0 Your boiler has encountered a technical internal error specifically relating to its main electronic control board which is preventing it from running.
Your boiler has encountered a technical internal error specifically relating to its main electronic control board which is preventing it from running.
Parts commonly replaced
- Main PCB (Control Unit)
- Coding Card
Related codes
7F:1 Your boiler’s internal control system has encountered a processing electronic fault, meaning it cannot properly communicate with its own internal components.
Your boiler’s internal control system has encountered a processing electronic fault, meaning it cannot properly communicate with its own internal components.
Parts commonly replaced
- Main PCB (Control Board)
- Electronic Controller
Related codes
08 Your boiler has detected a sequence of ignition or flame detection errors and has shut itself down for safety.
Your boiler has detected a sequence of ignition or flame detection errors and has shut itself down for safety.
Parts commonly replaced
- Ignition Electrode
- Ionisation Electrode
- Gas Valve
- Electronic Control Unit (PCB)
Related codes
09 Your boiler has detected a sequence error or a flame signal where there shouldn't be one, causing the burner to shut down completely for safety.
Your boiler has detected a sequence error or a flame signal where there shouldn't be one, causing the burner to shut down completely for safety.
Parts commonly replaced
- Ionisation electrode
- Ignition cable
- Burner control unit (PCB)
Related codes
9A Your boiler has lost communication with the temperature sensor that monitors the outdoor solar panels or the system collector, meaning it cannot accurately manage heat levels for those components.
Your boiler has lost communication with the temperature sensor that monitors the outdoor solar panels or the system collector, meaning it cannot accurately manage heat levels for those components.
Parts commonly replaced
- Collector temperature sensor (NTC)
- Sensor wiring harness
Related codes
Showing 41–50 of 211
9B Your boiler has lost communication with one of its internal heat sensors, meaning it cannot monitor temperatures accurately to operate safely.
Your boiler has lost communication with one of its internal heat sensors, meaning it cannot monitor temperatures accurately to operate safely.
Parts commonly replaced
- Low loss header sensor
- NTC thermistor
- Wiring harness
Related codes
9b:1 to 9b:127 Your boiler has detected an error with its internal temperature settings or the control unit, which may cause it to stop providing heating or hot water correctly.
Your boiler has detected an error with its internal temperature settings or the control unit, which may cause it to stop providing heating or hot water correctly.
Parts commonly replaced
- Electronic control PCB
- Control unit programming plug
- Sensor wiring loom
Related codes
9b:70 Your boiler has detected an incorrect setting or a communication error regarding the minimum water temperature required when an external control system asks for heat.
Your boiler has detected an incorrect setting or a communication error regarding the minimum water temperature required when an external control system asks for heat.
Parts commonly replaced
- External control interface
- Boiler control unit (PCB)
Related codes
9C Your boiler is unable to read the temperature of your hot water cylinder because the connection to the sensor has been lost or damaged.
Your boiler is unable to read the temperature of your hot water cylinder because the connection to the sensor has been lost or damaged.
Parts commonly replaced
- NTC Cylinder Temperature Sensor
- Sensor wiring harness
Related codes
9C:0 Your boiler has stopped working because its internal control computer has lost its configuration settings or is unable to communicate with its safety sensors.
Your boiler has stopped working because its internal control computer has lost its configuration settings or is unable to communicate with its safety sensors.
Parts commonly replaced
- Coding chip
- Main PCB
- Gas Valve sensor
Related codes
9C:5 to 9C:60 Your boiler is currently undergoing a pre-set maintenance test or a specialized calibration check that lasts between 5 and 60 minutes.
Your boiler is currently undergoing a pre-set maintenance test or a specialized calibration check that lasts between 5 and 60 minutes.
What to check first
- Wait for the timer to count down and the code to disappear naturally
- Check that you haven't accidentally entered a test mode via the control panel
- If the code persists for over an hour, try a simple reset of the boiler
Related codes
9C:20 Your boiler has lost communication with one of its internal control modules or an external smart accessory, causing it to use temporary backup settings.
Your boiler has lost communication with one of its internal control modules or an external smart accessory, causing it to use temporary backup settings.
What to check first
- Turn the boiler power off at the main fused spur switch.
- Wait for 30 seconds.
- Turn the power back on and see if the communication link re-establishes itself.
Parts commonly replaced
- LON communication module
- PCB (Main Controller)
- External sensor wiring
Related codes
9F Your boiler has lost communication with the solar heating control panel, meaning your solar panels won't be helping to heat your water.
Your boiler has lost communication with the solar heating control panel, meaning your solar panels won't be helping to heat your water.
What to check first
- Check if the solar control panel has power
- Switch the boiler off and back on at the fused spur switch to reset the connection
- Check for any loose external cables connecting the solar controller to the boiler if visible and safe
Parts commonly replaced
- Solar control module
- Communication cable
- Solar cylinder temperature sensor
Related codes
9F:0 to 9F:40 Your boiler is notifying you that it has reached a specific temperature difference limit you have set, which usually means the water is heating up faster or slower than expected.
Your boiler is notifying you that it has reached a specific temperature difference limit you have set, which usually means the water is heating up faster or slower than expected.
What to check first
- Check that all radiator valves are fully open
- Ensure the central heating system pressure is between 1.0 and 1.5 bar
- Bleed any air from radiators to ensure smooth water flow
Parts commonly replaced
- None (parameter adjustment)
- Circulation pump
- Temperature sensors (NTC)
Related codes
9F:8 Your secondary heating circuit is not reaching the required temperature difference to operate correctly, likely due to a flow or sensor issue in that specific zone.
Your secondary heating circuit is not reaching the required temperature difference to operate correctly, likely due to a flow or sensor issue in that specific zone.
Parts commonly replaced
- Mixer motor
- Temperature sensor
- Circulation pump
Related codes
Showing 51–60 of 211
10 Your boiler is struggling to accurately gauge the weather outside, meaning it might not provide the right amount of heat for your home.
Your boiler is struggling to accurately gauge the weather outside, meaning it might not provide the right amount of heat for your home.
Parts commonly replaced
- Outside temperature sensor
- NTC thermistor
- Wiring lead
Related codes
18 Your boiler has lost its connection to the outside temperature sensor, meaning it cannot automatically adjust your heating based on the weather.
Your boiler has lost its connection to the outside temperature sensor, meaning it cannot automatically adjust your heating based on the weather.
Parts commonly replaced
- Outside temperature sensor
- Sensor wiring
Related codes
20 Your boiler has detected an electrical fault with a sensor that monitors the water temperature flowing into your heating system, leading it to shut down for safety.
Your boiler has detected an electrical fault with a sensor that monitors the water temperature flowing into your heating system, leading it to shut down for safety.
Parts commonly replaced
- Flow temperature sensor (NTC)
- Sensor wiring harness
Related codes
21:0 Your boiler is simply notifying you that a routine service is due based on its operating hours.
Your boiler is simply notifying you that a routine service is due based on its operating hours.
23:0 Your boiler is simply reminding you that it is time for its regular annual service to ensure it continues running safely and efficiently.
Your boiler is simply reminding you that it is time for its regular annual service to ensure it continues running safely and efficiently.
24:0
Your boiler is simply indicating that no urgent service or maintenance is currently required at this time.
25 Your boiler is getting too hot too quickly and is shutting itself down to prevent damage.
Your boiler is getting too hot too quickly and is shutting itself down to prevent damage.
What to check first
- Check that your radiator valves are fully open
- Ensure the central heating pump is running
- Check if the system water pressure is between 1.0 and 1.5 bar
Parts commonly replaced
- Circulation pump
- Temperature sensors (NTC thermistors)
- Heat exchanger (descaling)
Related codes
25:0 Your boiler has lost the connection to the external sensor that tells it how cold it is outside, meaning it may not adjust its heating output as efficiently as usual.
Your boiler has lost the connection to the external sensor that tells it how cold it is outside, meaning it may not adjust its heating output as efficiently as usual.
Parts commonly replaced
- Outside temperature sensor
- Wiring harness
- Control PCB
25:1 Your boiler has lost the connection to the thermometer placed outside your home, so it cannot automatically adjust your heating based on the weather.
Your boiler has lost the connection to the thermometer placed outside your home, so it cannot automatically adjust your heating based on the weather.
Parts commonly replaced
- Outside temperature sensor
- Wiring loom/connection cable
Related codes
26 Your boiler's computer has become stuck in a repeating internal test sequence and is failing to move into its normal heating mode.
Your boiler's computer has become stuck in a repeating internal test sequence and is failing to move into its normal heating mode.
Parts commonly replaced
- Main VBC PCB (Control Board)
- Relay Module
Related codes
Showing 61–70 of 211
28 Your boiler has lost connection with a temperature sensor that monitors the main water flow, likely due to a broken wire or a faulty sensor.
Your boiler has lost connection with a temperature sensor that monitors the main water flow, likely due to a broken wire or a faulty sensor.
Parts commonly replaced
- Low loss header temperature sensor
- NTC thermistor
- Wiring harness
Related codes
28:0 Your boiler is failing to light the flame needed to produce heat or hot water.
Your boiler is failing to light the flame needed to produce heat or hot water.
Parts commonly replaced
- Ignition electrode
- Ignition transformer
- Gas valve
Related codes
30 Your boiler has stopped heating because a internal sensor that monitors water temperature has developed an electrical fault and is preventing the burner from firing.
Your boiler has stopped heating because a internal sensor that monitors water temperature has developed an electrical fault and is preventing the burner from firing.
Parts commonly replaced
- Boiler water temperature sensor (NTC thermistor)
- Wiring harness
Related codes
30:0 Your boiler has detected an issue with the water pump that moves heat around your radiators and taps, meaning it cannot circulate heat effectively.
Your boiler has detected an issue with the water pump that moves heat around your radiators and taps, meaning it cannot circulate heat effectively.
Parts commonly replaced
- Circulation pump
- Pump wiring harness
- Control board
32:0 Your boiler has been forced to shut down its water circulation pumps by an external safety device or a control signal from your heating system's management unit.
Your boiler has been forced to shut down its water circulation pumps by an external safety device or a control signal from your heating system's management unit.
Parts commonly replaced
- External safety interlock
- System control module
- Wiring harness
34:0 Your boiler is receiving a constant request for heat from an external control or thermostat, causing all the pumps to run continuously.
Your boiler is receiving a constant request for heat from an external control or thermostat, causing all the pumps to run continuously.
What to check first
- Check all room thermostats are not set excessively high
- Check if the programmers or timers are stuck on an 'Always On' setting
- Turn the boiler power off and back on at the fused spur to see if the signal resets
Parts commonly replaced
- External Room Thermostat
- Wiring Centre
- Control PCB
Related codes
34:1 Your boiler is receiving a specific signal from an external control or accessory that it doesn't currently know how to handle.
Your boiler is receiving a specific signal from an external control or accessory that it doesn't currently know how to handle.
What to check first
- Locate the reset button on the front control panel.
- Press and hold the reset button for 2 to 3 seconds.
- Wait for the boiler to restart; if the code returns, contact a professional to check the system configuration.
Parts commonly replaced
- None (Coding address adjustment)
- External Pump Controller
- Expansion PCB
Related codes
34:2 Your boiler is receiving a conflicting signal from an external control or accessory that is telling the pumps how to run incorrectly.
Your boiler is receiving a conflicting signal from an external control or accessory that is telling the pumps how to run incorrectly.
Parts commonly replaced
- Extension module
- Wiring harness
- External controller
Related codes
35 Your boiler has failed to ignite or stay lit, meaning your heating and hot water have stopped working.
Your boiler has failed to ignite or stay lit, meaning your heating and hot water have stopped working.
What to check first
- Check if your gas supply is active by testing another gas appliance like a hob.
- Try resetting the boiler using the 'R' or reset button on the control panel.
- Ensure your system pressure is between 1.0 and 1.5 bar on the pressure gauge.
Parts commonly replaced
- Ionisation Electrode
- Ignition Lead
- Gas Valve
- PCB
Related codes
38 Your boiler has stopped working because it can no longer accurately measure the temperature of the water inside the system.
Your boiler has stopped working because it can no longer accurately measure the temperature of the water inside the system.
Parts commonly replaced
- Boiler water temperature sensor (NTC thermistor)
- Connecting cable harness
Related codes
Showing 71–80 of 211
38:0 Your boiler is reporting a normal status update rather than a failure, indicating that the internal burner control system is currently operating correctly.
Your boiler is reporting a normal status update rather than a failure, indicating that the internal burner control system is currently operating correctly.
What to check first
- Check if the display returns to the home screen manually
- Perform a simple reset if the code persists on the display
- Monitor for any other numerical codes that may appear alongside it
40 Your boiler has stopped working because it thinks the hot water tank is dangerously overheating due to a faulty electrical sensor.
Your boiler has stopped working because it thinks the hot water tank is dangerously overheating due to a faulty electrical sensor.
Parts commonly replaced
- Cylinder temperature sensor (NTC)
- Sensor wiring harness
Related codes
48 Your boiler has stopped heating your hot water because it can no longer detect the temperature of your hot water cylinder.
Your boiler has stopped heating your hot water because it can no longer detect the temperature of your hot water cylinder.
Parts commonly replaced
- NTC Cylinder Temperature Sensor
- Wiring Harness
Related codes
50 Your boiler has stopped providing hot water because the internal sensor that measures water temperature has detected a technical fault or a short circuit.
Your boiler has stopped providing hot water because the internal sensor that measures water temperature has detected a technical fault or a short circuit.
Parts commonly replaced
- DHW Temperature Sensor (NTC thermistor)
- Connecting cable harness
Related codes
50:0 Your boiler's computer screen and main control board are having trouble communicating with each other.
Your boiler's computer screen and main control board are having trouble communicating with each other.
Parts commonly replaced
- HMI (Human Machine Interface) Control Unit
- Ribbon Cable Connection
- Electronic Power PCB
Related codes
50:1 Your boiler has detected a short circuit in the sensor that monitors your hot water temperature, meaning it can no longer accurately heat your tap water.
Your boiler has detected a short circuit in the sensor that monitors your hot water temperature, meaning it can no longer accurately heat your tap water.
Parts commonly replaced
- Cylinder temperature sensor
- Wiring harness
Related codes
50:3 Your boiler is struggling to monitor the temperature outside, which is preventing it from adjusting your heating efficiently.
Your boiler is struggling to monitor the temperature outside, which is preventing it from adjusting your heating efficiently.
Parts commonly replaced
- Outside temperature sensor
- Wiring harness
- Control PCB
Related codes
51 Your boiler has stopped working because a sensor that monitors the water temperature has developed an electrical fault.
Your boiler has stopped working because a sensor that monitors the water temperature has developed an electrical fault.
Parts commonly replaced
- Outlet temperature sensor (NTC thermistor)
- Wiring harness
Related codes
52:0 Your boiler is struggling to monitor the temperature of a specific part of your system's pipework, which may cause your heating to run less efficiently or stop working correctly.
Your boiler is struggling to monitor the temperature of a specific part of your system's pipework, which may cause your heating to run less efficiently or stop working correctly.
Parts commonly replaced
- Low loss header temperature sensor (NTC)
- Sensor wiring harness
Related codes
52:1 Your boiler is struggling to accurately measure the water temperature in a specific part of your heating system, which may cause your heating to run inefficiently or not at all.
Your boiler is struggling to accurately measure the water temperature in a specific part of your heating system, which may cause your heating to run inefficiently or not at all.
Parts commonly replaced
- Low loss header temperature sensor (NTC)
- Sensor wiring harness
Related codes
Showing 81–90 of 211
53:0 Your boiler has detected a general internal fault that is preventing it from running properly, often linked to an issue with the main control system or a signal error.
Your boiler has detected a general internal fault that is preventing it from running properly, often linked to an issue with the main control system or a signal error.
Parts commonly replaced
- Electronic Control Unit (PCB)
- Communication module
- Internal wiring harness
Related codes
53:1 Your boiler has detected a communication problem with the pump that circulates hot water around your taps, which may cause delays in getting hot water or stop it altogether.
Your boiler has detected a communication problem with the pump that circulates hot water around your taps, which may cause delays in getting hot water or stop it altogether.
Parts commonly replaced
- Internal Extension H1 or H2
- DHW Circulation Pump
- Wiring Harness
Related codes
53:2 Your boiler is having trouble communicating with the external pump that circulates hot water to your radiators, meaning your heating may not turn on correctly.
Your boiler is having trouble communicating with the external pump that circulates hot water to your radiators, meaning your heating may not turn on correctly.
Parts commonly replaced
- External circulation pump
- Wiring harness
- Internal PCB
Related codes
53:3 Your boiler is having trouble communicating with the pump that fills your external hot water tank, meaning your hot water supply may be affected.
Your boiler is having trouble communicating with the pump that fills your external hot water tank, meaning your hot water supply may be affected.
Parts commonly replaced
- External cylinder loading pump
- Relay 2 control module
- Wiring harness
Related codes
54:0 Your boiler is confused because it thinks it should be connected to a solar heating system that it cannot find.
Your boiler is confused because it thinks it should be connected to a solar heating system that it cannot find.
What to check first
- Locate the 'OK' and 'Menu' buttons (or the touchscreen menu).
- Navigate to the 'Service' or 'Settings' sub-menu.
- Restart the boiler using the main power switch to see if it clears the communication error.
Parts commonly replaced
- None (Software reconfiguration)
- Communication module
Related codes
54:1 Your solar heating system is experiencing a communication error or fault, which may affect how efficiently your water is heated.
Your solar heating system is experiencing a communication error or fault, which may affect how efficiently your water is heated.
Parts commonly replaced
- Communication cable
- Solar controller module
- Sensor
Related codes
54:2 Your boiler is having trouble communicating with the solar heating control module during its automatic setup process.
Your boiler is having trouble communicating with the solar heating control module during its automatic setup process.
Parts commonly replaced
- Vitosolic 200 module
- Communication cable
- Solar circuit sensor
Related codes
56:0 Your boiler is experiencing an issue where it cannot properly monitor or control the temperature of your hot water.
Your boiler is experiencing an issue where it cannot properly monitor or control the temperature of your hot water.
Parts commonly replaced
- DHW cylinder temperature sensor
- Wiring harness
- Sensor NTC lead
Related codes
56:1 Your boiler's hot water sensor is reporting an unusually high temperature range, which may prevent your hot water from heating correctly.
Your boiler's hot water sensor is reporting an unusually high temperature range, which may prevent your hot water from heating correctly.
Parts commonly replaced
- DHW cylinder temperature sensor
- NTC thermistor
- Wiring harness
Related codes
58 Your boiler has stopped providing hot water because the internal sensor that measures water temperature is broken or disconnected.
Your boiler has stopped providing hot water because the internal sensor that measures water temperature is broken or disconnected.
Parts commonly replaced
- Domestic Hot Water (DHW) temperature sensor
- Wiring harness
Related codes
Showing 91–100 of 211
58:0 Your boiler is struggling to heat your hot water tank because it cannot detect or communicate with a required external sensor or control module.
Your boiler is struggling to heat your hot water tank because it cannot detect or communicate with a required external sensor or control module.
Parts commonly replaced
- Cylinder temperature sensor
- NTC thermistor
- Extension module (internal wiring)
Related codes
58:1 to 58:95 Your boiler is notifying you that a specific setting for your hot water temperature has been manually adjusted or requested.
Your boiler is notifying you that a specific setting for your hot water temperature has been manually adjusted or requested.
What to check first
- Check your hot water temperature settings on the boiler control panel or app
- Ensure the temperature is set to a comfortable level (typically 50-60°C)
- Restart the boiler to clear the notification if the setting was adjusted by mistake
Related codes
59 Your boiler has stopped working because it cannot accurately measure the temperature of the water leaving the unit, usually due to a fault in a sensor or its wiring.
Your boiler has stopped working because it cannot accurately measure the temperature of the water leaving the unit, usually due to a fault in a sensor or its wiring.
Parts commonly replaced
- Outlet temperature sensor
- NTC thermistor
- Wiring harness
Related codes
59:0 Your boiler has detected an issue with the sensors that monitor the temperature of your hot water cylinder, which may lead to inconsistent water temperatures.
Your boiler has detected an issue with the sensors that monitor the temperature of your hot water cylinder, which may lead to inconsistent water temperatures.
Parts commonly replaced
- Cylinder temperature sensor
- NTC thermistor
- Wiring harness
Related codes
59:1 to 59:10 Your boiler has detected a minor internal setting inconsistency regarding when it should start heating, but it is unlikely to stop your hot water or heating from working.
Your boiler has detected a minor internal setting inconsistency regarding when it should start heating, but it is unlikely to stop your hot water or heating from working.
What to check first
- Press the 'Reset' button on the control panel
- Turn the boiler off and back on at the fused spur switch
- Monitor the display to see if the code clears after a restart
Parts commonly replaced
- Control PCB
- NTC Sensor
Related codes
60:5 to 60:25 Your boiler is struggling to reach the temperature requested for your hot water because the internal settings are set too high or a sensor is misreading.
Your boiler is struggling to reach the temperature requested for your hot water because the internal settings are set too high or a sensor is misreading.
Parts commonly replaced
- NTC temperature sensor
- DHW plate heat exchanger
Related codes
60:10 Your boiler is getting much hotter than it should while trying to heat your water, which usually means the heat isn't transferring correctly to your tank.
Your boiler is getting much hotter than it should while trying to heat your water, which usually means the heat isn't transferring correctly to your tank.
Parts commonly replaced
- Plate heat exchanger
- Diverter valve
- DHW temperature sensor
- External pump
Related codes
60:20 Your boiler is getting too hot while trying to heat your water, which usually means the heat isn't being transferred to your hot water tank quickly enough.
Your boiler is getting too hot while trying to heat your water, which usually means the heat isn't being transferred to your hot water tank quickly enough.
Parts commonly replaced
- Plate heat exchanger
- Diverter valve
- Temperature sensor
- Secondary pump
Related codes
62:0 Your boiler's internal pump is failing to stay on long enough to safely dissipate heat after the burner turns off, which can cause the system to overheat.
Your boiler's internal pump is failing to stay on long enough to safely dissipate heat after the burner turns off, which can cause the system to overheat.
Parts commonly replaced
- Internal circulation pump
- Control PCB
Related codes
62:1 to 62:15 Your boiler's pump is set to run for a specific amount of time after the heating switches off to help the system cool down safely.
Your boiler's pump is set to run for a specific amount of time after the heating switches off to help the system cool down safely.
What to check first
- Check your user manual to see if the run-on time is set to your preference
- Monitor the boiler to ensure it shuts down correctly after the timed period
- No action is required if the heating and hot water are functioning normally
Related codes
Showing 101–110 of 211
62:2 Your boiler has detected an issue with the internal pump's operation, causing it to run for a short safety cooling period before pausing.
Your boiler has detected an issue with the internal pump's operation, causing it to run for a short safety cooling period before pausing.
Parts commonly replaced
- Circulation pump
- Internal wiring harness
- Control PCB
Related codes
63:0 Your boiler is failing to communicate properly with the equipment used to heat your hot water tank, meaning you may lose hot water.
Your boiler is failing to communicate properly with the equipment used to heat your hot water tank, meaning you may lose hot water.
Parts commonly replaced
- KM-Bus Communication Module
- DHW Cylinder Sensor
- Internal Wiring Harness
63:1 Your boiler is performing a routine daily check to ensure the internal pump and components are not seized up.
Your boiler is performing a routine daily check to ensure the internal pump and components are not seized up.
What to check first
- No action required; this is a normal operating status message rather than a breakdown.
- Monitor the display to ensure it returns to the standard temperature reading automatically.
- If the code stays on the screen permanently, try a simple reset.
63:2 to 63:14 Your boiler is notifying you that a specific pre-set service interval or scheduled maintenance time has elapsed and a routine check-up is now required.
Your boiler is notifying you that a specific pre-set service interval or scheduled maintenance time has elapsed and a routine check-up is now required.
Parts commonly replaced
- No parts required (Service interval reset)
- Burner gasket (during routine service)
- Ionisation probe (preventative)
63:15 Your boiler has detected an internal electronic error that suggests the main control unit is beginning to fail, which may cause your heating and hot water to become unreliable.
Your boiler has detected an internal electronic error that suggests the main control unit is beginning to fail, which may cause your heating and hot water to become unreliable.
Parts commonly replaced
- Main PCB (Control Unit)
Related codes
65:0 Your boiler has lost communication with the internal valve that directs heated water to either your radiators or your hot water tank, meaning your system cannot function correctly.
Your boiler has lost communication with the internal valve that directs heated water to either your radiators or your hot water tank, meaning your system cannot function correctly.
Parts commonly replaced
- Diverter valve motor
- Wiring harness
- Internal electronic control board
Related codes
65:1 Your boiler is having trouble directing water to the right place, meaning you might not have any heating or hot water until it is fixed.
Your boiler is having trouble directing water to the right place, meaning you might not have any heating or hot water until it is fixed.
Parts commonly replaced
- Diverter valve motor
- Complete diverter valve assembly
Related codes
65:2 Your boiler is having trouble directing hot water between your taps and radiators due to a mechanical issue with a internal valve.
Your boiler is having trouble directing hot water between your taps and radiators due to a mechanical issue with a internal valve.
Parts commonly replaced
- Diverter valve motor
- Complete diverter valve assembly
Related codes
65:3 Your boiler is struggling to switch the flow of heated water between your radiators and your hot water taps because of an internal valve malfunction.
Your boiler is struggling to switch the flow of heated water between your radiators and your hot water taps because of an internal valve malfunction.
Parts commonly replaced
- 3-way diverter valve motor
- Diverter valve cartridge
- Wiring harness
Related codes
67:0 to 67:60 Your boiler has likely detected an internal configuration issue or a fault with the control board that manages your hot water settings.
Your boiler has likely detected an internal configuration issue or a fault with the control board that manages your hot water settings.
Parts commonly replaced
- Electronic Control Unit (PCB)
- Communication Module
Related codes
Showing 111–120 of 211
67:40 Your boiler is having trouble communicating with the solar heating controls, which may prevent your hot water from reaching the desired temperature.
Your boiler is having trouble communicating with the solar heating controls, which may prevent your hot water from reaching the desired temperature.
What to check first
- Locate your boiler's power switch and turn it off
- Wait for 30 seconds
- Turn the power back on to see if the communication fault clears
Parts commonly replaced
- Communication cable
- Vitosolic control module
- Temperature sensor
Related codes
71:0 Your boiler is notifying you that your hot water circulation pump is currently active based on its programmed schedule, which may be an advisory rather than a breakdown.
Your boiler is notifying you that your hot water circulation pump is currently active based on its programmed schedule, which may be an advisory rather than a breakdown.
What to check first
- Check your hot water time program settings on the control panel
- Ensure the pump is not running during hours when it is not needed to save energy
- Reset the boiler to see if the advisory message clears
Parts commonly replaced
- None (Settings adjustment)
- DHW Circulation Pump
Related codes
71:1 Your boiler is switching itself off because it is struggling to reach the correct temperature while trying to heat your hot water tank.
Your boiler is switching itself off because it is struggling to reach the correct temperature while trying to heat your hot water tank.
Parts commonly replaced
- Cylinder temperature sensor
- Diverter valve motor
- Plate heat exchanger
Related codes
71:2 Your boiler is having trouble heating your hot water cylinder because a sensor has detected an unusually high temperature or a fault during the heating process.
Your boiler is having trouble heating your hot water cylinder because a sensor has detected an unusually high temperature or a fault during the heating process.
Parts commonly replaced
- Cylinder temperature sensor
- Diverter valve
- Plate heat exchanger
Related codes
72:0 Your boiler is notifying you that the hot water circulation pump is currently active based on its set schedule, though it may indicate a minor communication lag with the sensor.
Your boiler is notifying you that the hot water circulation pump is currently active based on its set schedule, though it may indicate a minor communication lag with the sensor.
What to check first
- Check your hot water time program settings to ensure the 'On' period is intentional
- Turn the boiler off at the main isolation switch for 30 seconds and restart it
- Monitor the display to see if the code clears once the scheduled period ends
Parts commonly replaced
- None
- DHW pump cable
Related codes
72:1 Your boiler is switching itself off unexpectedly while trying to heat your hot water tank because a temperature sensor is detecting an unusual reading.
Your boiler is switching itself off unexpectedly while trying to heat your hot water tank because a temperature sensor is detecting an unusual reading.
Parts commonly replaced
- Cylinder temperature sensor
- NTC thermistor
- Wiring harness
Related codes
72:2 Your boiler has detected that hot water is being heated when it shouldn't be, which is usually caused by a faulty sensor or a sticking internal valve.
Your boiler has detected that hot water is being heated when it shouldn't be, which is usually caused by a faulty sensor or a sticking internal valve.
Parts commonly replaced
- Cylinder temperature sensor
- NTC thermistor
- Diverter valve
Related codes
73:0 Your boiler's hot water circulation pump is currently active based on its programmed timer settings.
Your boiler's hot water circulation pump is currently active based on its programmed timer settings.
What to check first
- Check the hot water time program settings on your control panel
- Adjust the 'Circulation Pump' schedule if the pump is running when you do not need it
- Monitor the boiler to ensure it returns to standby once the scheduled period ends
73:1 to 73:6 Your boiler is notifying you that the hot water cylinder's circulation pump is running on a preset timed cycle to prevent legionella or keep the water warm, rather than responding to a specific heating demand.
Your boiler is notifying you that the hot water cylinder's circulation pump is running on a preset timed cycle to prevent legionella or keep the water warm, rather than responding to a specific heating demand.
What to check first
- This is often a status notification rather than a breakdown.
- Check your hot water time program settings on the control panel.
- Ensure your legionella protection or DHW circulation pump settings match your daily needs.
Parts commonly replaced
- None (Settings adjustment)
- Circulation pump (if failing)
Related codes
73:7 Your boiler communication module has a permanent fault that is preventing the system from talking to its controls correctly.
Your boiler communication module has a permanent fault that is preventing the system from talking to its controls correctly.
Parts commonly replaced
- Communication module (LON)
- Electronic control PCB
Related codes
Showing 121–130 of 211
76:0 Your boiler's internal communication system is failing to connect with other smart controls or external heating modules.
Your boiler's internal communication system is failing to connect with other smart controls or external heating modules.
Parts commonly replaced
- LON Communication Module
- Internal Ribbon Cable
- Electronic Control Board
Related codes
76:1 Your boiler is having difficulty communicating with its internal smart connection module, usually meaning there is a minor electronic glitch or a connection has come loose.
Your boiler is having difficulty communicating with its internal smart connection module, usually meaning there is a minor electronic glitch or a connection has come loose.
What to check first
- Switch off the power to the boiler at the main fused spur
- Wait for 30 seconds
- Switch the power back on and wait for the system to reboot
- Check if the fault code cleared; if it persists, contact a heating engineer
Parts commonly replaced
- LON communication module
- Internal ribbon cable
- Main PCB
Related codes
76:2 Your boiler is having trouble communicating with its internal control modules or multiple boiler system systems, which may stop it from operating correctly.
Your boiler is having trouble communicating with its internal control modules or multiple boiler system systems, which may stop it from operating correctly.
Parts commonly replaced
- KMBUS Communication Module
- Electronic Control PCB
- Wiring harness
Related codes
77:1 Your boiler's internal communication system has detected an issue or a duplicate identity on its data network, which can sometimes happen after a power cut or part change.
Your boiler's internal communication system has detected an issue or a duplicate identity on its data network, which can sometimes happen after a power cut or part change.
What to check first
- Locate the 'Reset' button or menu option on the control panel.
- Perform a full system reset as per the user manual.
- Turn the power off at the fused spur switch for 30 seconds, then turn it back on.
Parts commonly replaced
- LON communication module
- PCB (Main control board)
Related codes
77:2 to 77:99 Your boiler's internal communication system has identified an addressing conflict between different control units on the network.
Your boiler's internal communication system has identified an addressing conflict between different control units on the network.
Parts commonly replaced
- LON communication module
- Vitotronic control board
Related codes
79:0 Your boiler's internal control panel is having a communication error and is struggling to coordinate with other linked components in the system.
Your boiler's internal control panel is having a communication error and is struggling to coordinate with other linked components in the system.
What to check first
- Locate the main power switch for the boiler and turn it off.
- Wait for approximately 60 seconds.
- Turn the power back on and press the 'Reset' button on the front control panel.
Parts commonly replaced
- Electronic Control Unit (PCB)
- HMI Control Module
- Bus Communication Cable
Related codes
79:1 Your boiler's main control unit has detected an internal communication error and is struggling to manage the various components of the heating system.
Your boiler's main control unit has detected an internal communication error and is struggling to manage the various components of the heating system.
Parts commonly replaced
- Electronic control board (PCB)
- Wiring harness
- Bus communication module
Related codes
80:0 Your boiler is experiencing a communication error between its control system and the temperature sensors, meaning it cannot accurately monitor the water temperature.
Your boiler is experiencing a communication error between its control system and the temperature sensors, meaning it cannot accurately monitor the water temperature.
Parts commonly replaced
- NTC temperature sensor
- Wiring harness
- Main PCB
Related codes
80:1 Your boiler has detected a communication error with its internal sensors or control unit that has lasted for more than five seconds.
Your boiler has detected a communication error with its internal sensors or control unit that has lasted for more than five seconds.
Parts commonly replaced
- Flow temperature sensor
- Wiring harness
- Control PCB
Related codes
80:2 to 80:199 Your boiler is pausing temporarily to prevent it from switching on and off too frequently, which helps protect the internal components.
Your boiler is pausing temporarily to prevent it from switching on and off too frequently, which helps protect the internal components.
What to check first
- Check if the display returns to normal operation after 15 minutes
- Ensure your thermostat is set to a temperature that requires heat
- Monitor the boiler to see if the code reappears frequently, which may indicate a settings adjustment is needed
Parts commonly replaced
- None (parameter adjustment only)
Showing 131–140 of 211
81:0 Your boiler has been manually switched to a mode where it only provides hot water and has turned the central heating off for the season.
Your boiler has been manually switched to a mode where it only provides hot water and has turned the central heating off for the season.
What to check first
- Locate the control panel on the front of the boiler
- Access the menu settings to find 'Heating and Hot Water' mode
- Switch the setting from 'Summer mode' back to 'Heating and Hot Water' to re-enable your radiators
81:1 Your boiler is notifying you that it has automatically switched between summer and winter mode based on the external temperature.
Your boiler is notifying you that it has automatically switched between summer and winter mode based on the external temperature.
What to check first
- Check your external temperature sensor for any obstructions or damage
- Review your heating settings if the boiler switched modes at an unexpected time
- No action is required if your heating and hot water are working as desired
Related codes
81:2 Your boiler is having trouble communicating with its external radio clock module, meaning it may not know the correct time or date for your heating schedule.
Your boiler is having trouble communicating with its external radio clock module, meaning it may not know the correct time or date for your heating schedule.
What to check first
- Locate the radio clock module (usually a small white box near the boiler) and ensure it is not blocked by metal objects.
- Restart the boiler using the power switch to trigger a fresh search for the signal.
- Access the 'Time and Date' settings via the control panel to manually set the time if the signal cannot be found.
Parts commonly replaced
- Radio clock receiver module
- Communication cable
Related codes
81:3 Your boiler is having trouble synchronizing its clock with other connected parts of your heating system.
Your boiler is having trouble synchronizing its clock with other connected parts of your heating system.
What to check first
- Navigate to the 'Settings' or 'Menu' on your control panel
- Look for the 'Time' and 'Date' settings
- Manually update the time and date then save the settings to clear the notification
Parts commonly replaced
- None - usually a settings configuration
- LON communication module (rare)
Related codes
88:0 Your boiler is operating normally, but the display settings have been changed or reset to show temperatures in Celsius.
Your boiler is operating normally, but the display settings have been changed or reset to show temperatures in Celsius.
What to check first
- Navigate to the display settings menu
- Select the temperature unit option
- Confirm your preferred unit (°C or °F) to clear the status message
88:1 Your boiler is simply displaying the temperature in Fahrenheit instead of Celsius due to a settings change.
Your boiler is simply displaying the temperature in Fahrenheit instead of Celsius due to a settings change.
What to check first
- Navigate to the main menu on the control panel
- Select 'Settings'
- Change the temperature unit from '°F' back to '°C'
90:0 to 90:199 Your boiler is struggling to adjust the heating temperature correctly in response to changes in the weather outside.
Your boiler is struggling to adjust the heating temperature correctly in response to changes in the weather outside.
Parts commonly replaced
- Outside temperature sensor
- Wiring connections
- Control PCB
Related codes
90:128 Your boiler is receiving an unusual signal from the outdoor temperature sensor, likely due to a minor communication error or a faulty sensor outside your home.
Your boiler is receiving an unusual signal from the outdoor temperature sensor, likely due to a minor communication error or a faulty sensor outside your home.
Parts commonly replaced
- Outdoor temperature sensor
- External sensor wiring
Related codes
91:0 Your boiler is having trouble communicating with an external control accessory, meaning some remote settings or external commands might not be working as expected.
Your boiler is having trouble communicating with an external control accessory, meaning some remote settings or external commands might not be working as expected.
What to check first
- Locate your boiler's power switch and turn it off for 30 seconds, then turn it back on to reset the communication.
- Check if any external smart home controllers or extensions are unplugged or have lost power.
- Confirm that your thermostat or external control unit is displaying information and has fresh batteries if applicable.
Parts commonly replaced
- H5 Extension module
- OpenTherm interface
- Communication wiring
Related codes
91:1 Your boiler has detected an external control conflict where a heating setting is trying to communicate with a part of the system that isn't configured to receive it.
Your boiler has detected an external control conflict where a heating setting is trying to communicate with a part of the system that isn't configured to receive it.
What to check first
- Check any external heating controllers or smart thermostats for conflicting schedule settings.
- Perform a simple reset of the boiler using the power button to clear the communication glitch.
- Verify if any external 'party mode' or 'holiday mode' switches have been accidentally toggled.
Parts commonly replaced
- External controller
- Wiring harness
Related codes
Showing 141–150 of 211
91:2 Your boiler is experiencing a communication issue with the accessory that controls different temperature zones in your home, often caused by a temporary wiring hitch or a sensor problem.
Your boiler is experiencing a communication issue with the accessory that controls different temperature zones in your home, often caused by a temporary wiring hitch or a sensor problem.
Parts commonly replaced
- Mixer module
- Connection cable
- External sensor
Related codes
91:3 Your boiler's control system is receiving conflicting instructions regarding how your heating cycles should run across your different radiators or zones.
Your boiler's control system is receiving conflicting instructions regarding how your heating cycles should run across your different radiators or zones.
What to check first
- Check your external thermostat or heating app for conflicting schedule settings
- Ensure all external controls are calling for heat correctly
- Reset the boiler using the power button to clear temporary communication glitches
Parts commonly replaced
- External programmer
- Wiring harness
- Control PCB
Related codes
92 Your solar heating system has a faulty sensor or a wiring problem that is preventing it from correctly monitoring the temperature of the roof panels.
Your solar heating system has a faulty sensor or a wiring problem that is preventing it from correctly monitoring the temperature of the roof panels.
Parts commonly replaced
- Solar collector temperature sensor (NTC)
- Sensor wiring harness
Related codes
93 Your boiler has detected a technical fault with a sensor in your solar heating system, which may affect its ability to heat your water using solar energy.
Your boiler has detected a technical fault with a sensor in your solar heating system, which may affect its ability to heat your water using solar energy.
Parts commonly replaced
- Solar cylinder temperature sensor
- Sensor wiring harness
Related codes
94 Your boiler has lost communication with the temperature sensor in your hot water tank because of an electrical fault, meaning it cannot accurately monitor your solar heated water.
Your boiler has lost communication with the temperature sensor in your hot water tank because of an electrical fault, meaning it cannot accurately monitor your solar heated water.
Parts commonly replaced
- Cylinder temperature sensor (NTC)
- Sensor wiring harness
Related codes
95:0 Your boiler is trying to connect to a remote control accessory that it cannot find or which has lost power.
Your boiler is trying to connect to a remote control accessory that it cannot find or which has lost power.
What to check first
- Check if your Vitocom internet gateway or remote control hub is plugged in and powered on
- Check your home internet router is working correctly
- Press the Reset button on the boiler control panel
Parts commonly replaced
- Vitocom 100 communication module
- Connecting cables/ribbons
Related codes
95:1 Your boiler has detected an issue communicating with its remote control or internet connection module during the initial setup process.
Your boiler has detected an issue communicating with its remote control or internet connection module during the initial setup process.
What to check first
- Check that your internet router is switched on and working
- Ensure all cables connecting the Vitocom module to the boiler are firmly plugged in
- Turn the boiler power off and back on again to trigger a fresh automatic search
Parts commonly replaced
- Vitocom 100 communication module
- Connecting cable harness
Related codes
97:0 Your boiler is noting a change in how it reads the outside temperature, but it is typically just an internal setting update and should not stop your heating.
Your boiler is noting a change in how it reads the outside temperature, but it is typically just an internal setting update and should not stop your heating.
What to check first
- Press the 'OK' or 'Reset' button on the control panel to clear the notification
- Check for any other fault codes that might be appearing alongside it
- Monitor the boiler to ensure it is still providing heating and hot water as normal
Parts commonly replaced
- None (Software logic adjustment)
- Outside temperature sensor
Related codes
97:1 Your boiler is receiving the outdoor weather information from another connected device on your home network rather than its own direct sensor.
Your boiler is receiving the outdoor weather information from another connected device on your home network rather than its own direct sensor.
What to check first
- Check if any other connected heating controls or smart home devices have been recently updated or restarted
- Press the 'Reset' button on the boiler control panel
- Monitor the boiler display; if your heating is working normally, no further action is required
Parts commonly replaced
- None (Software communication update)
- LON communication module
Related codes
97:2 Your boiler is having trouble communicating with the outdoor temperature sensor, which helps the system run more efficiently based on the weather.
Your boiler is having trouble communicating with the outdoor temperature sensor, which helps the system run more efficiently based on the weather.
Parts commonly replaced
- Outdoor temperature sensor
- LON communication module
- Sensor wiring
Related codes
Showing 151–160 of 211
98:1 Your boiler is experiencing a communication error with an external remote monitoring system, meaning the central hub cannot correctly read your heating data.
Your boiler is experiencing a communication error with an external remote monitoring system, meaning the central hub cannot correctly read your heating data.
What to check first
- Check the power supply to the Vitocom 300 communication module
- Ensure the LAN or internet cable is securely plugged into the module
- Reset the communication module by turning it off and back on again
Parts commonly replaced
- Vitocom 300 Communication Module
- Communication cables
- Internal coding plug
98:1 to 98:5 Your boiler is confused because it doesn't know which type of heating system it is supposed to be controlling.
Your boiler is confused because it doesn't know which type of heating system it is supposed to be controlling.
Parts commonly replaced
- Main PCB (Control Unit)
- Coding Plug
Related codes
A0:0 Your boiler has lost communication with its external thermostat or control unit, meaning it may not know when to turn your heating on or off.
Your boiler has lost communication with its external thermostat or control unit, meaning it may not know when to turn your heating on or off.
What to check first
- Check if your wireless thermostat has run out of batteries and replace them if necessary.
- Ensure the thermostat or remote control unit is within range of the boiler.
- Restart the boiler using the power button to see if it re-establishes a connection.
Parts commonly replaced
- Thermostat batteries
- Wireless receiver
- External room thermostat
Related codes
A0:1 Your boiler has lost communication with its remote control thermostat, meaning it cannot receive temperature instructions.
Your boiler has lost communication with its remote control thermostat, meaning it cannot receive temperature instructions.
What to check first
- Check that the Vitotrol remote unit is properly docked in its wall base.
- Inspect the wiring between the remote and the boiler for any loose connections or damage.
- Restart the boiler to trigger a new automatic recognition scan.
Parts commonly replaced
- Vitotrol 200 Remote Control
- Communication cable
- Internal boiler interface module
Related codes
A0:2 Your boiler is having trouble communicating with the wall-mounted room controller and may need a simple reset to re-establish the connection.
Your boiler is having trouble communicating with the wall-mounted room controller and may need a simple reset to re-establish the connection.
What to check first
- Check that the Vitotrol unit is securely clicked into its wall docking station
- Switch the boiler power off at the main isolation switch for 30 seconds, then back on
- Ensure the wiring to the wall controller has not been accidentally damaged or disconnected
Parts commonly replaced
- Vitotrol 300 Remote Control
- KM-BUS Communication Module
Related codes
A2 Your boiler has sensed that the internal pump is malfunctioning or water is not circulating correctly, which has caused the system to stop as a safety precaution.
Your boiler has sensed that the internal pump is malfunctioning or water is not circulating correctly, which has caused the system to stop as a safety precaution.
Parts commonly replaced
- Circulation pump
- Internal pump head
- Control PCB
Related codes
A2:0 Your boiler is currently ignoring the standard priority for hot water and is attempting to provide heating and hot water at the same time, which may result in lukewarm water or poor heating performance.
Your boiler is currently ignoring the standard priority for hot water and is attempting to provide heating and hot water at the same time, which may result in lukewarm water or poor heating performance.
Parts commonly replaced
- Diverter Valve Motor
- NTC Cylinder Temperature Sensor
- PCB
Related codes
A2:1 Your boiler is currently focused on heating your hot water tank, so it has temporarily paused the central heating to ensure you have enough hot water.
Your boiler is currently focused on heating your hot water tank, so it has temporarily paused the central heating to ensure you have enough hot water.
What to check first
- Wait for the hot water tank to reach its target temperature
- Check if the hot water timer or 'boost' function is active
- Once the water is hot, the heating should automatically restart
Related codes
A2:2 Your boiler is likely experiencing a communication or pump error where it is struggling to switch between heating your house and heating your hot water tank.
Your boiler is likely experiencing a communication or pump error where it is struggling to switch between heating your house and heating your hot water tank.
Parts commonly replaced
- Circulation pump
- KM-Bus connection cable
- Logic PCB
Related codes
A3:-9 to A3:15 Your boiler is automatically managing its pump based on the outdoor temperature to prevent your pipes from freezing.
Your boiler is automatically managing its pump based on the outdoor temperature to prevent your pipes from freezing.
What to check first
- Check if your outdoor sensor is covered by snow or debris
- Monitor your radiators to ensure they are getting warm as expected
- No action is required as this is a normal frost protection function
Showing 161–170 of 211
A5 Your boiler has detected that the water pump is likely stuck or not moving water correctly, which means the system cannot heat up safely.
Your boiler has detected that the water pump is likely stuck or not moving water correctly, which means the system cannot heat up safely.
Parts commonly replaced
- Internal circulation pump
- Pump motor head
- Main PCB
Related codes
A5:0 Your boiler has detected that the water pump responsible for circulating heat to your radiators is not behaving as expected, which may result in your heating not working correctly.
Your boiler has detected that the water pump responsible for circulating heat to your radiators is not behaving as expected, which may result in your heating not working correctly.
Parts commonly replaced
- Circulation pump
- Pump control cable/wiring harness
- PCB
A5:5 Your boiler has temporarily stopped the heating pump to prevent it from running unnecessarily, which is a normal part of its energy-saving settings.
Your boiler has temporarily stopped the heating pump to prevent it from running unnecessarily, which is a normal part of its energy-saving settings.
Related codes
A7 Your boiler's control panel has developed a communication fault and is unable to send or receive correctly.
Your boiler's control panel has developed a communication fault and is unable to send or receive correctly.
Parts commonly replaced
- Programming unit
- User interface (HMI)
- Control PCB
Related codes
A8 Your boiler's main internal computer has lost touch with the display panel, meaning the controls cannot talk to the heating unit.
Your boiler's main internal computer has lost touch with the display panel, meaning the controls cannot talk to the heating unit.
Parts commonly replaced
- Control Unit PCB
- HMU Programming Unit
- Internal Ribbon Cable
Related codes
A9 Your boiler is having trouble 'talking' to your thermostat, which means it might not know when to turn your heating on or off.
Your boiler is having trouble 'talking' to your thermostat, which means it might not know when to turn your heating on or off.
What to check first
- Check that your thermostat is powered on and has fresh batteries if applicable.
- Restart the boiler using the power switch or reset button to refresh the connection.
- Ensure the thermostat wiring is securely plugged into its base if it is a wall-mounted unit.
Parts commonly replaced
- OpenTherm Thermostat
- Communication Module
- Wiring harness
Related codes
b0 Your boiler has detected an electrical fault with the sensor that monitors the temperature of the exhaust gases, causing the system to shut down for safety.
Your boiler has detected an electrical fault with the sensor that monitors the temperature of the exhaust gases, causing the system to shut down for safety.
Parts commonly replaced
- Flude gas temperature sensor (NTC)
- Wiring harness
Related codes
b1 Your boiler's main control panel is having trouble talking to its own internal computer, meaning you cannot change settings or control the heating properly.
Your boiler's main control panel is having trouble talking to its own internal computer, meaning you cannot change settings or control the heating properly.
What to check first
- Locate the main power switch for the boiler (usually a fused spur on the wall).
- Turn the power off, wait for 60 seconds, and turn it back on to reboot the system.
- Ensure the control panel is pushed firmly into its housing if it is a removable type.
Parts commonly replaced
- Programming unit
- Main PCB (Control board)
- Wiring harness
Related codes
b4 Your boiler has encountered an internal electronic communication error that is preventing it from monitoring its own performance correctly.
Your boiler has encountered an internal electronic communication error that is preventing it from monitoring its own performance correctly.
Parts commonly replaced
- Printed Circuit Board (PCB)
- Electronic Control Box
Related codes
b5 Your boiler has experienced an internal communication error or processor glitch that is preventing it from running properly.
Your boiler has experienced an internal communication error or processor glitch that is preventing it from running properly.
What to check first
- Locate the power switch or fused spur for the boiler
- Turn the power off, wait for 30 seconds, and turn it back on
- Press the 'Reset' button on the boiler control panel once
Parts commonly replaced
- Electronic Control Unit (PCB)
- Wiring harness
Related codes
Showing 171–180 of 211
b7 Your boiler's internal computer chip has been disconnected or has developed a communication fault, meaning the system doesn't know which settings to use.
Your boiler's internal computer chip has been disconnected or has developed a communication fault, meaning the system doesn't know which settings to use.
Parts commonly replaced
- Boiler Coding Card
- Ignition Control Circuit Board
Related codes
b8 Your boiler has detected a broken connection or a fault with the sensor that monitors the temperature of the exhaust gases, causing the system to stop working for safety.
Your boiler has detected a broken connection or a fault with the sensor that monitors the temperature of the exhaust gases, causing the system to stop working for safety.
Parts commonly replaced
- Flue gas temperature sensor
- Wiring harness
- Sensor clip
Related codes
bA Your boiler is having trouble communicating with the control box that manages your second heating zone, meaning that specific area may not heat up correctly.
Your boiler is having trouble communicating with the control box that manages your second heating zone, meaning that specific area may not heat up correctly.
Parts commonly replaced
- Mixer extension kit electronics
- KM-BUS communication cable
- Mixer motor
Related codes
bc Your boiler has lost its connection with the remote control unit used to manage your primary heating circuit.
Your boiler has lost its connection with the remote control unit used to manage your primary heating circuit.
What to check first
- Check if the batteries in your Vitotrol unit need replacing
- Ensure the remote control is correctly docked in its wall bracket
- Turn the boiler power off and back on at the fused spur to reset the connection
Parts commonly replaced
- Vitotrol 200/300 Remote Control unit
- Communication wiring
- Bus communication module
Related codes
bd Your boiler has lost connection with the remote control unit that manages your second heating zone, meaning you cannot adjust the temperature for that specific area.
Your boiler has lost connection with the remote control unit that manages your second heating zone, meaning you cannot adjust the temperature for that specific area.
What to check first
- Check if the Vitotrol remote unit is properly seated on its wall base
- Switch the boiler off at the fused spur, wait 30 seconds, and switch it back on to reset the connection
- Inspect the remote unit batteries (if applicable) or check for visible damage to the wiring leading to the unit
Parts commonly replaced
- Vitotrol 200/300 Remote Control unit
- Low voltage communication wiring
- LON communication module
Related codes
be Your boiler is having trouble communicating with the wall-mounted thermostat control because of a setup or configuration error.
Your boiler is having trouble communicating with the wall-mounted thermostat control because of a setup or configuration error.
Parts commonly replaced
- Vitotrol 200/300 Remote Control
- Control Unit PCB
- Communication Cable
Related codes
bF Your boiler is currently stuck in an automated filling process and cannot continue until this is resolved.
Your boiler is currently stuck in an automated filling process and cannot continue until this is resolved.
Parts commonly replaced
- External Filling Loop Valve
- Boiler Control Unit (PCB)
- Electronic Pressure Sensor
Related codes
C2 Your boiler is having trouble 'talking' to your solar panels or an additional heating control part, which might prevent those specific systems from working correctly.
Your boiler is having trouble 'talking' to your solar panels or an additional heating control part, which might prevent those specific systems from working correctly.
What to check first
- Locate the power switch (fused spur) for the boiler.
- Turn the power off, wait for 30 seconds, and turn it back on to see if the connection resets.
- Check if any external solar controllers or expansion boxes have lost power or been unplugged.
Parts commonly replaced
- KM-Bus connection cable
- SM1 Solar Control Module
- Internal expansion PCB
Related codes
C5 Your boiler is having trouble communicating with its internal pump, which means it cannot properly move heated water around your system.
Your boiler is having trouble communicating with its internal pump, which means it cannot properly move heated water around your system.
Parts commonly replaced
- Internal circulation pump
- Pump communication cable
- Main PCB
Related codes
C5:20 Your boiler has detected that the water temperature is currently lower than its minimum safety setting and is pausing to protect the system.
Your boiler has detected that the water temperature is currently lower than its minimum safety setting and is pausing to protect the system.
Parts commonly replaced
- Flow temperature sensor
- NTC sensor
Showing 181–190 of 211
C6 Your boiler is having trouble communicating with the internal pump that moves hot water around your heating system.
Your boiler is having trouble communicating with the internal pump that moves hot water around your heating system.
Parts commonly replaced
- Variable speed pump
- Pump communication cable
- Main PCB
Related codes
C6:75 Your boiler has detected that the water temperature is too hot and has automatically limited it to prevent damage to your heating system.
Your boiler has detected that the water temperature is too hot and has automatically limited it to prevent damage to your heating system.
Parts commonly replaced
- Flow temperature sensor
- Heat exchanger
- PCB
C7 Your boiler is having trouble communicating with the internal pump that moves hot water through your radiators, which may prevent your heating from working correctly.
Your boiler is having trouble communicating with the internal pump that moves hot water through your radiators, which may prevent your heating from working correctly.
Parts commonly replaced
- Internal circulation pump
- Wiring harness
- Main PCB
Related codes
Cd Your boiler has lost its connection to the remote control or internet monitoring system, so you may not be able to adjust settings via your app or external thermostat.
Your boiler has lost its connection to the remote control or internet monitoring system, so you may not be able to adjust settings via your app or external thermostat.
What to check first
- Check that your internet router is switched on and working
- Ensure the Vitocom 100 communication module is firmly plugged into the boiler
- Turn the boiler power off and back on again to restart the communication link
Parts commonly replaced
- Vitocom 100 LAN/WLAN module
- Connecting cable
Related codes
CE Your boiler is having trouble communicating with an add-on control or an external smart home accessory, which may affect its ability to run efficiently.
Your boiler is having trouble communicating with an add-on control or an external smart home accessory, which may affect its ability to run efficiently.
What to check first
- Check if any external smart thermostats or controllers are turned on and have battery power.
- Restart the boiler by turning the power off and back on at the fused spur switch.
- Ensure any wireless hubs or range extenders nearby are plugged in and working.
Parts commonly replaced
- External extension module (H5)
- Wiring harness
- OpenTherm gateway
Related codes
CF Your boiler is having trouble 'talking' to its internal Wi-Fi or internet connection module, which may prevent you from controlling it via apps or external thermostats.
Your boiler is having trouble 'talking' to its internal Wi-Fi or internet connection module, which may prevent you from controlling it via apps or external thermostats.
What to check first
- Turn the boiler off at the main power switch for 30 seconds, then turn it back on to reboot the electronics.
- Check your home internet router is working correctly and within range of the boiler.
- Verify that any external smart thermostats or bridges are powered on and connected.
Parts commonly replaced
- Communication module (WiFi/LAN)
- Electronic controller (PCB)
Related codes
d3:14
This code is simply an information display showing the current heating settings rather than an actual fault with your boiler.
d4:0 Your boiler's heating control settings have been reset to zero, meaning it does not currently know it needs to provide heating to your home.
Your boiler's heating control settings have been reset to zero, meaning it does not currently know it needs to provide heating to your home.
What to check first
- Access the boiler control panel menu
- Navigate to the Heating Curve settings
- Adjust the 'Level' or 'Shift' parameter to your desired comfort setting to reactivate the heating schedule
dA Your boiler has lost its connection to the indoor temperature sensor for your main heating area, meaning it cannot accurately tell how warm your rooms are.
Your boiler has lost its connection to the indoor temperature sensor for your main heating area, meaning it cannot accurately tell how warm your rooms are.
Parts commonly replaced
- Room temperature sensor
- Wiring harness
- NTC thermistor
Related codes
db Your boiler has lost the ability to monitor the temperature in your second heating zone because a sensor has developed an electrical fault.
Your boiler has lost the ability to monitor the temperature in your second heating zone because a sensor has developed an electrical fault.
Parts commonly replaced
- Room temperature sensor (NTC)
- Sensor wiring harness
Related codes
Showing 191–200 of 211
dE Your boiler has lost connection with the temperature sensor that controls your second heating zone, meaning it cannot properly regulate the temperature for that part of your home.
Your boiler has lost connection with the temperature sensor that controls your second heating zone, meaning it cannot properly regulate the temperature for that part of your home.
Parts commonly replaced
- Room temperature sensor (NTC)
- Sensor wiring harness
- M2 extension module
Related codes
E4 Your boiler has stopped working because it is not receiving the correct electrical power or an internal fuse has blown.
Your boiler has stopped working because it is not receiving the correct electrical power or an internal fuse has blown.
Parts commonly replaced
- Internal Fuses
- Electronic Control PCB
- Ignition Transformer
Related codes
E5 Your boiler has stopped working because it cannot confirm that a flame is burning safely, leading to a complete shutdown for your protection.
Your boiler has stopped working because it cannot confirm that a flame is burning safely, leading to a complete shutdown for your protection.
Parts commonly replaced
- Ionisation electrode
- Ignition lead
- Burner control unit
- Gas valve
Related codes
E6 Your boiler has stopped working because there is not enough water flowing through the system to keep it running safely.
Your boiler has stopped working because there is not enough water flowing through the system to keep it running safely.
What to check first
- Check the pressure gauge on the front of the boiler; if it is below 1.0 bar, top it up using the filling loop.
- Ensure all radiator valves are fully open to allow water to circulate.
- Gently bleed air from your radiators using a radiator key.
Parts commonly replaced
- Circulation pump
- Heat exchanger
- Flow sensor
Related codes
EL Your boiler is currently running an automatic air-purging program to remove air bubbles from the system and does not require a repair.
Your boiler is currently running an automatic air-purging program to remove air bubbles from the system and does not require a repair.
What to check first
- Wait approximately 20 minutes for the automated venting process to complete
- Check that the system water pressure is between 1.0 and 1.5 bar
- The code should disappear and be replaced by the normal temperature display once finished
Related codes
F0 Your boiler has experienced a serious internal brain failure and the main control board likely needs to be replaced.
Your boiler has experienced a serious internal brain failure and the main control board likely needs to be replaced.
Parts commonly replaced
- Main PCB (Control Unit)
- Wiring Harness
Related codes
F1 Your boiler has switched itself off because it has reached a dangerously high temperature, likely due to a lack of water or poor circulation.
Your boiler has switched itself off because it has reached a dangerously high temperature, likely due to a lack of water or poor circulation.
What to check first
- Check the pressure gauge and top up the water if it is below 1.5 bar
- Bleed all radiators to remove trapped air from the system
- Ensure all radiator valves and isolation valves are fully open
- Reset the boiler after checking water levels
Parts commonly replaced
- Circulation pump
- Flue gas temperature sensor
- Heat exchanger (flushing service)
Related codes
F2 Your boiler has shut down because it has detected it is getting too hot, which is usually caused by a lack of water or a circulation problem.
Your boiler has shut down because it has detected it is getting too hot, which is usually caused by a lack of water or a circulation problem.
What to check first
- Check the pressure gauge on your boiler and top up the water if it is below 1.5 bar
- Ensure all your radiator valves are open and not switched off
- Once the boiler has cooled down, press the 'Reset' button to see if the fault clears
Parts commonly replaced
- Circulation Pump
- Temperature Limiter (Overheat Thermostat)
- Wiring harness
Related codes
F3 Your boiler is detecting a flame when there shouldn't be one, so it has shut down for safety purposes to prevent a malfunction.
Your boiler is detecting a flame when there shouldn't be one, so it has shut down for safety purposes to prevent a malfunction.
Parts commonly replaced
- Ionisation electrode
- Ignition lead
- Burner control unit (PCB)
Related codes
F4 Your boiler has failed to light the flame, which means it cannot provide any heating or hot water until the issue is resolved.
Your boiler has failed to light the flame, which means it cannot provide any heating or hot water until the issue is resolved.
What to check first
- Check if other gas appliances in your home, like a hob, are working to confirm your gas supply is active.
- Ensure your gas meter has credit if you use a prepay meter.
- Press the Reset button on the boiler control panel once to see if the fault clears.
Parts commonly replaced
- Ignition Electrode
- Ionisation Lead
- Gas Valve
- Ignition Module
Related codes
Showing 201–210 of 211
F5 Your boiler has identified a problem with the ventilation system and has shut down as a safety precaution because it cannot confirm that exhaust fumes are being cleared correctly.
Your boiler has identified a problem with the ventilation system and has shut down as a safety precaution because it cannot confirm that exhaust fumes are being cleared correctly.
Parts commonly replaced
- Air pressure switch
- Fan assembly
- Venturi tubes
Related codes
F7 Your boiler has stopped working because it cannot correctly detect the water pressure, causing the system to shut down for safety.
Your boiler has stopped working because it cannot correctly detect the water pressure, causing the system to shut down for safety.
Parts commonly replaced
- Water pressure sensor
- Pressure sensor wiring harness
Related codes
F8 Your boiler has detected a problem with the gas valve not closing correctly, so it has shut down the burner for safety.
Your boiler has detected a problem with the gas valve not closing correctly, so it has shut down the burner for safety.
Parts commonly replaced
- Gas valve assembly
- Cables and wire harness
- Control PCB
Related codes
F9 Your boiler has stopped working because the internal fan isn't spinning fast enough to safely start the heating process.
Your boiler has stopped working because the internal fan isn't spinning fast enough to safely start the heating process.
Parts commonly replaced
- Fan assembly
- Fan wiring harness
- PCB (Control board)
Related codes
FA Your boiler has failed to start properly and the fan is running constantly to clear out the system, preventing the heater from firing up.
Your boiler has failed to start properly and the fan is running constantly to clear out the system, preventing the heater from firing up.
Parts commonly replaced
- Fan motor
- Fan wiring harness
- Main control PCB
Related codes
FC Your boiler has shut down because it cannot correctly control the flow of gas needed to stay alight.
Your boiler has shut down because it cannot correctly control the flow of gas needed to stay alight.
Parts commonly replaced
- Gas valve
- Modulation coil
- Electronic control PCB
Related codes
Fd Your boiler's internal computer has crashed due to an ignition failure or electrical interference, preventing it from starting the burner.
Your boiler's internal computer has crashed due to an ignition failure or electrical interference, preventing it from starting the burner.
What to check first
- Press the reset button or turn the boiler off and back on at the fused spur switch
- Ensure large electronic devices or powerful wireless routers are not sitting directly next to the boiler
- Check if other gas appliances in your home are working to ensure gas is reaching the property
Parts commonly replaced
- Ignition electrodes
- Ignition leads
- Electronic control unit (PCB)
Related codes
FE Your boiler's internal computer has encountered a critical error or is having trouble communicating with its electronic security card, causing the system to shut down for safety.
Your boiler's internal computer has encountered a critical error or is having trouble communicating with its electronic security card, causing the system to shut down for safety.
Parts commonly replaced
- Coding Card
- Printed Circuit Board (PCB)
- Control Unit
Related codes
Filling Your boiler is currently in the process of being filled with water, and the control system is waiting for the pressure to reach the correct level before it can start working again.
Your boiler is currently in the process of being filled with water, and the control system is waiting for the pressure to reach the correct level before it can start working again.
What to check first
- Locate the filling loop (a flexible silver hose) underneath your boiler or near your pipework.
- Gradually open the valves on the filling loop to allow water into the system.
- Monitor the pressure gauge on the front of the boiler until it reaches the green zone (typically between 1.0 and 1.5 bar).
- Close both valves firmly once the pressure is correct.
nF1 Your boiler has detected trapped air inside it which is preventing it from starting up safely.
Your boiler has detected trapped air inside it which is preventing it from starting up safely.
What to check first
- Check that the radiator valves are open and the system is fully topped up with water to the correct pressure (usually 1.5 bar).
- Bleed all radiators in the house to remove any trapped air pockets.
- Restart the boiler to trigger the automatic venting program.
Parts commonly replaced
- Automatic Air Vent
- System Pump
Related codes
Showing 211–211 of 211
Venting
Your boiler is currently running a routine automated process to clear trapped air from its internal system.
Status & diagnostic codes 2 operating states & engineer diagnostics
Not faults — these are normal operating states. Tap to expand.
2 operating states & engineer diagnostics
Not faults — these are normal operating states. Tap to expand.