Discover the most common boiler fault codes.
Our experienced engineers are on hand to diagnose
and fix your boiler and central heating issues
throughout South London.
Boiler Fault Codes
Having an issue with your boiler?
We're always on hand to help with any repairs and always recommend if you do think your boiler is showing any of these fault codes, a Gas Safe engineer should examine and determine the fault.
Vaillant
Vaillant Fault Codes
| Fault Code | Possible Cause | |
| F.00 / F.0 | Flow temperature sensor interruption | |
| F.01 / F.1 | Return temperature sensor interruption | |
| F.10 | Flow NTC short circuit | |
| F.11 | Return NTC short circuit | |
| F.20 | Safety switch off temperature limiter | |
| F.22 | Safety switch off low water pressure | |
| F.23 | Safety switch off temperature difference too great | |
| F.24 | Safety switch off temperature is rising to fast | |
| F.25 | Safety switch off flue gas temperature too high | |
| F.26 | Error with gas valve – possible no function | |
| F.27 | Safety switch off flame simulation | |
| F.28 | Failure during start up – ignition unsuccessful to start | |
| F.29 | Failure during operation – re-ignition unsuccessful | |
| F.32 | Fan error | |
| F.49 | eBUS error – possible short circuit | |
| F.61 | Error with gas valve regulation | |
| F.62 | Error with gas valve – switch off delay | |
| F.63 | EEPROM error | |
| F.64 | Electronics / NTC error | |
| F.65 | Electronic temperature error could be overheating due to external influences | |
| F.67 | Electronics flame signal error | |
| F.68 | Unstable flame signal error air in gas | |
| F.70 | Invalid device specific number (DSN) | |
| F.71 | Flow NTC error – flow temperature sensor signal constant value | |
| F.72 | Flow return NTC error – temperature difference too great | |
| F.73 | Water pressure sensor signal in the wrong range, it is too low | |
| F.74 | Water pressure sensor signal outside correct range, the sensor signal is too high | |
| F.75 | Error with pressure – no pressure change detection when starting the pump | |
| F.76 | Overheating protection on – primary heat exchanger has responded | |
| F.77 | Flue non return flap condensate pump error | |
| F.78 | Interruption to DHW outlet sensor at external controller | |
| F.83 | Flow and or return temperature sensor error | |
| F.84 | Error with flow/return temperature sensor temperature changing error | |
| F.85 | Error with flow and return temperature, sensor incorrectly fitted | |
| CONNECTION | No communication with the PCB |
| Fault Code | Possible Cause | |
| F.1 | Lack of gas, a fault with the ignition or flue – may need to adjust the gas valve or replace a defective electrode lead. | |
| F.4 | Ignition fault. | |
| F.5 | The system has suffered a fault due to overheating. | |
| F.6 | Your flow NTC has developed a fault. | |
| F.17 | Check the polarity of your system. | |
| F.24 | Pump-related faults – the pump could have failed, it may have over run or there could be an issue with the airlock |
| Fault Code | Possible Cause | |
| F.00 | NTC Faults | |
| F.04 | NTC Faults | |
| F.05 | NTC Faults | |
| F.10 | NTC Faults | |
| F.14 | NTC Faults | |
| F.15 | NTC Faults | |
| F.21 | The pilot flame has failed. | |
| F.22 | There is insufficient water in your system. | |
| F.11 | A blockage in the appliance is preventing the system from flowing as it should. | |
| F.12 | A blockage in the appliance is affecting the system’s pressure. | |
| F.13 | The appliance is blocked because of a water deficiency. |
| Fault Code | Possible Cause | |
| F.00 | NTC Faults | |
| F.01 | NTC Faults | |
| F.10 | NTC Faults | |
| F.11 | NTC Faults | |
| F.13 | NTC Faults | |
| F.20 | Boiler has exceeded the maximum temperature and needs to cool down | |
| F.22 | Dry fire / Low water in system / Overheat | |
| F.24 | Low water / Pump Failure / Blockage | |
| F.28 | Either insufficient gas in the system, a defective electrode, ignition lead or electronic ignitor | |
| F.29 | Flame extinguished | |
| F.60 | Gas valve control defective | |
| F.61 | Gas valve control defective | |
| F.62 | Defective gas valve closure mechanism | |
| F.63 | EEPROM (Electrically Erasable Programmable Read-Only Memory) error | |
| F.64 | Electronic system or sensor fault | |
| F.65 | Electronic system temperature too high | |
| F.67 | Electronic fault in the flame system |
Vaillant Status Codes
| Status Code | Possible Cause | |
| S.0 | Heating issue, no heat demand | |
| S.1 | Fan start-up error | |
| S.2 | Pump flow error | |
| S.3 | Heating mode error – ignition problem | |
| S.4 | Heat mode – burner on error | |
| S.6 | Heating mode – fan overrun error | |
| S.7 | Heating mode – pump overrun error | |
| S.8 | Heating remaining cut off for X amount of time | |
| S.31 | No heat demand summer operating mode | |
| S.34 | Heating mode frost protection error | |
| S.20 | Hot water requirement error | |
| S.22 | Hot water handling pump flow error | |
| S.24 | Hot water operation burner is on | |
| S.85 | Service message quantity of circulation water |
| S.00 | Heating mode error – no heat demand | |
| S.01 | Heating mode fan start-up | |
| S.02 | Heating mode error – water pump running | |
| S.03 | Heating mode – ignition sequence error | |
| S.04 | Heating mode – burner ignited | |
| S.06 | Heating mode – fan overrun error | |
| S.07 | Heating mode – pump overrun error | |
| S.08 | Heating remaining cut off time X minutes | |
| S.10 | Hot water demand via impeller sensor | |
| S.11 | DHW mode fan start up error | |
| S13 | DHW mode ignition error | |
| S.14 | Hot water demand via fan sensor error | |
| S.15 | DHW mode pump and fan overrun | |
| S.16 | DHW mode – fan overrun error | |
| S.17 | DHW mode – pump overrun error | |
| S.20 | DHW mode – burner on error | |
| S.21 | DHW mode – fan start up error | |
| S.22 | DHW demand – error pump running | |
| S.23 | DHW ignition error | |
| S.24 | DHW mode – burner error | |
| S.25 | DHW mode – pump or fan overrun error | |
| S.26 | DHW mode – fan overrun | |
| S.27 | DHW mode – pump overrun | |
| S.28 | Hot water burner anti-cycling time | |
| S.30 | Room thermostat is blocking heating mode | |
| S.31 | No heat demand boiler in summer operating mode | |
| S.32 | Waiting period because of fan speed deviation | |
| S.34 | Heating mode frost protection error | |
| S.39 | Burner off contact has been triggered this could be because of contact thermostat or condensate pump | |
| S.40 | Comfort safety mode active | |
| S.41 | Water pressure > 2.8 bar | |
| S.42 | Flue non return flap return signal blocks burner operation | |
| S.46 | Comfort safety mode flame loss at minimum load | |
| S.53 | Boiler is in waiting period of modulation f block function due to water shortage | |
| S.54 | Boiler is in waiting period of operation, blocking function as a result | |
| S.57 | Waiting period comfort safety mode | |
| S.58 | Modulation limitation due to noise / wind error | |
| S.61 | Gas family check unsuccessful |
Vaillant Demand Codes
| Demand Code | Possible Cause | |
| D.0 | Heating part load error | |
| D.1 | Water pump overrun – time for heat mode | |
| D.2 | Max burner anti-cycling period at 20c flow temperature | |
| D.3 | Hot water flow temperature reading | |
| D.4 | Current temperature for warm stat sensor | |
| D.5 | Set value of flow temperature or target value of return | |
| D.7 | Warm start temperature target value | |
| D.8 | External controls heat demand | |
| D.9 | Flow target temperature from external analogue regulator terminal | |
| D.10 | Status internal heating pump error | |
| D.11 | Status external heating pump error | |
| D.12 | Cylinder charging pump via accessory module | |
| D.13 | Hot water circulation pump | |
| D.15 | Pump speed actual value | |
| D.22 | Hot water demand | |
| D.23 | Summer/Winter function | |
| D.24 | Not relevant | |
| D.25 | Hot water activation via eBus control | |
| D.30 | Control signal for both gas valves | |
| D.33 | Fan speed target value | |
| D.34 | Fan speed actual value | |
| D.35 | Not relevant | |
| D.40 | Flow temperature target value | |
| D.41 | Return temperature actual value | |
| D.44 | Digitised ionisation – potential error | |
| D.47 | Outside temperature with weather compensator – Vaillant controller only | |
| D.76 | Remaining burner anti-cycling time in min | |
| D.90 | Digital regulator status | |
| D.91 | DCF status with connected external probe | |
| D.97 | Activation of the second diagnostic level | |
| D.98 | Telephone a heating engineer | |
| D.14 | Pump speed target value | |
| D.17 | Heating flow return regulation | |
| D.18 | Pump operating mode | |
| D.20 | Maximum set value for target cylinder | |
| D.26 | Additional relay control ecoTec | |
| D.27 | Switching accessory relay 1 | |
| D.28 | Switching accessory relay 2 | |
| D.50 | Offset for minimum speed | |
| D.51 | Offset for maximum speed | |
| D.60 | Number of safety temperature cut offs | |
| D.61 | Number of unsuccessful lockouts | |
| D.64 | Average ignition times | |
| D.65 | Maximum ignition time | |
| D.67 | Remaining burner anti-cycling time | |
| D.68 | Unsuccessful ignitions in the first attempt | |
| D.69 | Unsuccessful ignition for the second time | |
| D.70 | Set diverter valve position | |
| D.71 | Maximum setting of heater control knob | |
| D.72 | Pump overrun time after warm start | |
| D.75 | Maximum charging time for a storage without own controller | |
| D.77 | Limitation of cylinder charging in output in kW | |
| D.78 | Limitation of cylinder charging temperature in celsius | |
| D.80 | Operating hours heating | |
| D.81 | Operating hours hot water generation | |
| D.82 | Burner start up in heating mode | |
| D.83 | Burner start up in hot water mode | |
| D.84 | Maintenance indicator – number of hours until the next maintenance | |
| D.93 | DSN appliance variant setting | |
| D.96 | Factory setting |
| Status Code | Possible Cause | |
| S.0 | Heating issue, no heat demand | |
| S.1 | Fan start-up error | |
| S.2 | Pump flow error | |
| S.3 | Heating mode error – ignition problem | |
| S.4 | Heat mode – burner on error | |
| S.6 | Heating mode – fan overrun error | |
| S.7 | Heating mode – pump overrun error | |
| S.8 | Heating remaining cut off for X amount of time | |
| S.31 | No heat demand summer operating mode | |
| S.34 | Heating mode frost protection error | |
| S.20 | Hot water requirement error | |
| S.22 | Hot water handling pump flow error | |
| S.24 | Hot water operation burner is on | |
| S.85 | Service message quantity of circulation water |
| Fault Code | Possible Cause | |
| F.00 / F.0 | Flow temperature sensor interruption | |
| F.01 / F.1 | Return temperature sensor interruption | |
| F.10 | Flow NTC short circuit | |
| F.11 | Return NTC short circuit | |
| F.20 | Safety switch off temperature limiter | |
| F.22 | Safety switch off low water pressure | |
| F.23 | Safety switch off temperature difference too great | |
| F.24 | Safety switch off temperature is rising to fast | |
| F.25 | Safety switch off flue gas temperature too high | |
| F.26 | Error with gas valve – possible no function | |
| F.27 | Safety switch off flame simulation | |
| F.28 | Failure during start up – ignition unsuccessful to start | |
| F.29 | Failure during operation – re-ignition unsuccessful | |
| F.32 | Fan error | |
| F.49 | eBUS error – possible short circuit | |
| F.61 | Error with gas valve regulation | |
| F.62 | Error with gas valve – switch off delay | |
| F.63 | EEPROM error | |
| F.64 | Electronics / NTC error | |
| F.65 | Electronic temperature error could be overheating due to external influences | |
| F.67 | Electronics flame signal error | |
| F.68 | Unstable flame signal error air in gas | |
| F.70 | Invalid device specific number (DSN) | |
| F.71 | Flow NTC error – flow temperature sensor signal constant value | |
| F.72 | Flow return NTC error – temperature difference too great | |
| F.73 | Water pressure sensor signal in the wrong range, it is too low | |
| F.74 | Water pressure sensor signal outside correct range, the sensor signal is too high | |
| F.75 | Error with pressure – no pressure change detection when starting the pump | |
| F.76 | Overheating protection on – primary heat exchanger has responded | |
| F.77 | Flue non return flap condensate pump error | |
| F.78 | Interruption to DHW outlet sensor at external controller | |
| F.83 | Flow and or return temperature sensor error | |
| F.84 | Error with flow/return temperature sensor temperature changing error | |
| F.85 | Error with flow and return temperature, sensor incorrectly fitted | |
| CONNECTION | No communication with the PCB | |
| S.00 | Heating mode error – no heat demand | |
| S.01 | Heating mode fan start-up | |
| S.02 | Heating mode error – water pump running | |
| S.03 | Heating mode – ignition sequence error | |
| S.04 | Heating mode – burner ignited | |
| S.06 | Heating mode – fan overrun error | |
| S.07 | Heating mode – pump overrun error | |
| S.08 | Heating remaining cut off time X minutes | |
| S.10 | Hot water demand via impeller sensor | |
| S.11 | DHW mode fan start up error | |
| S13 | DHW mode ignition error | |
| S.14 | Hot water demand via fan sensor error | |
| S.15 | DHW mode pump and fan overrun | |
| S.16 | DHW mode – fan overrun error | |
| S.17 | DHW mode – pump overrun error | |
| S.20 | DHW mode – burner on error | |
| S.21 | DHW mode – fan start up error | |
| S.22 | DHW demand – error pump running | |
| S.23 | DHW ignition error | |
| S.24 | DHW mode – burner error | |
| S.25 | DHW mode – pump or fan overrun error | |
| S.26 | DHW mode – fan overrun | |
| S.27 | DHW mode – pump overrun | |
| S.28 | Hot water burner anti-cycling time | |
| S.30 | Room thermostat is blocking heating mode | |
| S.31 | No heat demand boiler in summer operating mode | |
| S.32 | Waiting period because of fan speed deviation | |
| S.34 | Heating mode frost protection error | |
| S.39 | Burner off contact has been triggered this could be because of contact thermostat or condensate pump | |
| S.40 | Comfort safety mode active | |
| S.41 | Water pressure > 2.8 bar | |
| S.42 | Flue non return flap return signal blocks burner operation | |
| S.46 | Comfort safety mode flame loss at minimum load | |
| S.53 | Boiler is in waiting period of modulation f block function due to water shortage | |
| S.54 | Boiler is in waiting period of operation, blocking function as a result | |
| S.57 | Waiting period comfort safety mode | |
| S.58 | Modulation limitation due to noise / wind error | |
| S.61 | Gas family check unsuccessful |
| Demand Code | Possible Cause | |
| D.0 | Heating part load error | |
| D.1 | Water pump overrun – time for heat mode | |
| D.2 | Max burner anti-cycling period at 20c flow temperature | |
| D.3 | Hot water flow temperature reading | |
| D.4 | Current temperature for warm stat sensor | |
| D.5 | Set value of flow temperature or target value of return | |
| D.7 | Warm start temperature target value | |
| D.8 | External controls heat demand | |
| D.9 | Flow target temperature from external analogue regulator terminal | |
| D.10 | Status internal heating pump error | |
| D.11 | Status external heating pump error | |
| D.12 | Cylinder charging pump via accessory module | |
| D.13 | Hot water circulation pump | |
| D.15 | Pump speed actual value | |
| D.22 | Hot water demand | |
| D.23 | Summer/Winter function | |
| D.24 | Not relevant | |
| D.25 | Hot water activation via eBus control | |
| D.30 | Control signal for both gas valves | |
| D.33 | Fan speed target value | |
| D.34 | Fan speed actual value | |
| D.35 | Not relevant | |
| D.40 | Flow temperature target value | |
| D.41 | Return temperature actual value | |
| D.44 | Digitised ionisation – potential error | |
| D.47 | Outside temperature with weather compensator – Vaillant controller only | |
| D.76 | Remaining burner anti-cycling time in min | |
| D.90 | Digital regulator status | |
| D.91 | DCF status with connected external probe | |
| D.97 | Activation of the second diagnostic level | |
| D.98 | Telephone a heating engineer | |
| D.14 | Pump speed target value | |
| D.17 | Heating flow return regulation | |
| D.18 | Pump operating mode | |
| D.20 | Maximum set value for target cylinder | |
| D.26 | Additional relay control ecoTec | |
| D.27 | Switching accessory relay 1 | |
| D.28 | Switching accessory relay 2 | |
| D.50 | Offset for minimum speed | |
| D.51 | Offset for maximum speed | |
| D.60 | Number of safety temperature cut offs | |
| D.61 | Number of unsuccessful lockouts | |
| D.64 | Average ignition times | |
| D.65 | Maximum ignition time | |
| D.67 | Remaining burner anti-cycling time | |
| D.68 | Unsuccessful ignitions in the first attempt | |
| D.69 | Unsuccessful ignition for the second time | |
| D.70 | Set diverter valve position | |
| D.71 | Maximum setting of heater control knob | |
| D.72 | Pump overrun time after warm start | |
| D.75 | Maximum charging time for a storage without own controller | |
| D.77 | Limitation of cylinder charging in output in kW | |
| D.78 | Limitation of cylinder charging temperature in celsius | |
| D.80 | Operating hours heating | |
| D.81 | Operating hours hot water generation | |
| D.82 | Burner start up in heating mode | |
| D.83 | Burner start up in hot water mode | |
| D.84 | Maintenance indicator – number of hours until the next maintenance | |
| D.93 | DSN appliance variant setting | |
| D.96 | Factory setting |
| Fault Code | Possible Cause | |
| F.1 | Lack of gas, a fault with the ignition or flue – may need to adjust the gas valve or replace a defective electrode lead. | |
| F.4 | Ignition fault. | |
| F.5 | The system has suffered a fault due to overheating. | |
| F.6 | Your flow NTC has developed a fault. | |
| F.17 | Check the polarity of your system. | |
| F.24 | Pump-related faults – the pump could have failed, it may have over run or there could be an issue with the airlock |
| Fault Code | Possible Cause | |
| F.00 | NTC Faults | |
| F.04 | NTC Faults | |
| F.05 | NTC Faults | |
| F.10 | NTC Faults | |
| F.14 | NTC Faults | |
| F.15 | NTC Faults | |
| F.21 | The pilot flame has failed. | |
| F.22 | There is insufficient water in your system. | |
| F.11 | A blockage in the appliance is preventing the system from flowing as it should. | |
| F.12 | A blockage in the appliance is affecting the system’s pressure. | |
| F.13 | The appliance is blocked because of a water deficiency. |
| Fault Code | Possible Cause | |
| F.00 | NTC Faults | |
| F.01 | NTC Faults | |
| F.10 | NTC Faults | |
| F.11 | NTC Faults | |
| F.13 | NTC Faults | |
| F.20 | Boiler has exceeded the maximum temperature and needs to cool down | |
| F.22 | Dry fire / Low water in system / Overheat | |
| F.24 | Low water / Pump Failure / Blockage | |
| F.28 | Either insufficient gas in the system, a defective electrode, ignition lead or electronic ignitor | |
| F.29 | Flame extinguished | |
| F.60 | Gas valve control defective | |
| F.61 | Gas valve control defective | |
| F.62 | Defective gas valve closure mechanism | |
| F.63 | EEPROM (Electrically Erasable Programmable Read-Only Memory) error | |
| F.64 | Electronic system or sensor fault | |
| F.65 | Electronic system temperature too high | |
| F.67 | Electronic fault in the flame system |
Worcester Bosch
The Worcester Bosch Ri range can display a blue flashing light when there's no gas being supplied to the boiler.
You can determine whether there is a fault with the boiler or your gas supply by checking any other gas appliances you have in your home, such as a gas hob.
If they are in working order then the issue is likely to be with the boiler.
Over time boilers can lose pressure and when they get too low, they can affect your heating system.
As well as the blue flashing light and the CE 207 error code, you can see if the pressure is low by checking whether the pressure gauge is below 1.
If it is below 1, the pressure will need to be increased.
A flue blockage can affect your boiler from igniting.
Flue guards are added to prevent debris and waste falling into them however if you don't have one fitted or it's been damaged, a Gas Safe registered engineer can fit or repair them.
If you can hear your boiler making banging noises, it could be a sign of kettling, a build up of limescale.
A Gas Safe registered heating engineer can offer a powerflush to remove any debris, sludge and limescale allowing clean water to flow through your system once again without any banging noises.
All condensing boilers have a condensate pipe that sends water waste out to a drain.
These pipes can then become blocked and often freeze during the winter months, leading to blockages.
Frozen condensate pipes can sometimes be thawed by pouring hot water on the blockage however if you're unsure, a Gas Safe registered engineer can be hired to examine and help clear any blockages.
If you're boiler is leaking, it's more than likely coming from a broken part inside the boiler.
If you do notice your boiler is leaking, turn off your water supply and contact a Gas Safe registered engineer to examine and determine the issue.
Ideal
Rotate all knobs fully clockwise
Turn the boiler off
Turn the boiler back on and then press restart
Reset the boiler
If this does not fix the problem, please contact us quoting error code L4 as this will require a visit from an engineer.
The boiler has been reset too many times in 15 minutes.
Turn the power to the boiler on and off again to reset
Please contact us as this will require a visit from an engineer.
The flow and return differential is wrong and may have been installed correctly / possible crossed pipes.
Please contact us as this will require a visit from an engineer.
There difference between the water flow and return is too high (more than 50⁰)
Turn the boiler off and bleed/let out the air of your radiators. Ensure the boiler pressure is still at 1 to 1.5 BAR and turn the boiler back on.
Possible blockage, please contact us quoting error code FU (we won't take offence) as this will require a visit from an engineer.
View our video on how to top up your boiler pressure:
Turn the boiler off and bleed/let out the air of your radiators. Ensure the boiler pressure is still at 1 to 1.5 BAR and turn the boiler back on.
Your central heating pump may not be running. Gently touch it and if it's working properly, there should be a gentle vibration and it should also be warm
If you believe the central heating pump is NOT running, contact your installer.
If you believe the central heating pump is running, please contact us quoting error code FA as this will require a visit from an engineer.
View our video on how to top up your boiler pressure:
Reset the boiler
If this does not fix the problem, please contact us quoting error code C0 as this will require a visit from an engineer.
Reset the boiler
If this does not fix the problem, please contact us quoting error code C2 as this will require a visit from an engineer.
Reset the boiler
If this does not fix the problem, please contact us quoting error code F0 as this will require a visit from an engineer.
Voltage to the boiler may be too low
Contact a local electrician to inspect the electrics of your property
Reset the boiler
If this does not fix the problem, please contact us quoting error code F6 as this will require a visit from an engineer.
Reset the boiler
If this does not fix the problem, please contact us quoting error code F5 as this will require a visit from an engineer.
Reset the boiler
If this does not fix the problem, please contact us quoting error code F4 as this will require a visit from an engineer.
Reset the boiler
If this does not fix the problem, please contact us quoting error code F3 as this will require a visit from an engineer.
Reset the boiler
If your gas meter is pay-as-you-go, check there is credit available
Check other gas powered items in your home, if these are also not working, you should contact a local gas engineer
Check that the yellow gas isolation valve under the boiler hasn't been turned off. If it is on, the handle/knob will be in pointing in the direction of the pipe.
If the boiler is making a gurgling/garglign noise whilst trying to fire, please contact your installer as there may be a blockage
If this does not fix the problem, call us quoting Error Code F2
Water pressure is too low in the system and will require topping up to between 1 and 1.5 BAR
View our video on how to top up your boiler pressure:
Reset the boiler
If this does not fix the problem, please contact us quoting error code L6 as this will require a visit from an engineer.
The boiler has been reset too many times in 15 minutes.
Turn the power to the boiler on and off again to reset
Check that the water pressure to the boiler is at 1 to 1.5 BAR.
Check that the yellow gas isolation valve under the boiler hasn't been turned off. If it is on, the handle/knob will be in pointing in the direction of the pipe
Turn the boiler off and bleed/let out the air of your radiatiors. Ensure the boiler pressur is still at 1 to 1.5 BAR and turn the boiler back on
Press the reset button
If this does not fix the problem, please contact us quoting error code L3
View our video on how to top up your boiler pressure:
Reset the boiler
If your gas meter is pay-as-you-go, check there is credit available
Check other gas powered items in your home, if these are also not working, you should contact a local gas engineer
Check that the yellow gas isolation valve under the boiler hasn't been turned off. If it is on, the handle/knob will be in pointing in the direction of the pipe.
If the boiler is making a gurgling/gargling noise whilst trying to fire, please contact your installer as there may be a blockage
If this does not fix the problem, call us quoting Error Code L2
Ensure that all radiator valves are open Check that the water pressure to the boiler is at 1 to 1.5 BAR.
View our video on how to top up your boiler pressure here.
Reset the boiler
If this does not fix the problem, please contact us
Baxi
Temporary Fault - Temporary loss of communication between gas valve and boiler board. Fault in air/gas unit.
Loose connection to gas valve.
Temporary Fault - Maximum difference between the flow and return temperature exceeded. Non-existent or insufficient circulation. Sensor error.
Temporary Fault - Flow temperature increasing too fast in heating mode. Non-existent or insufficient circulation.
Sensor error.
Temporary Fault - Maximum flow temperature value exceeded. Non-existent or insufficient circulation. Non-existent or insufficient circulation.
Temporary Fault - No circulation of water. Non-existent or insufficient circulation. Sensor error.
Temporary Fault - Flow temperature increasing too fast in DHW mode. Non-existent or insufficient circulation. Sensor error.
Temporary Fault - No input of parameters C1/C2. PCB not configured.
Temporary Fault- Incorrect configuration settings C1/C2.
Temporary Fault - Parameter error. Incorrect parameters.
Temporary Fault - System water pressure. Water leak on boiler. Water leak on system.
Temporary Fault - Communication error with NTC flue sensor. Sensor not, or badly connected. Bad connection. Sensor fault.
Temporary Fault - Communication error with the HMI PCB. HMI not connected.
Temporary Fault - No flame during operation. No ionization current.
Permanent Fault - Return temperature sensor open-circuit. Sensor not or badly connected. Bad connection. Sensor fault.
Permanent Fault - Return temperature sensor open-circuit. Sensor not or badly connected. Bad connection. Sensor fault.
Permanent Fault - Temperature measured by return sensor greater than flow sensor. Bad connection. Sensor fault. Sensor not or badly connected.
Permanent Fault - Loss of flame detected 5 times in 24 hours (With burner on). No ionization current.
Permanent Fault Requiring Reset - Incorrect fan speed. External draught over the boiler. Defective gas/air unit.
Permanent Fault Requiring Reset - Temperature measured by return sensor greater than flow temperature.
Permanent Fault Requiring Reset - No circulation. Sensor not or badly connected. Sensor fault.
Permanent Fault - Maximum flue gas temperature value reached (>140 Deg C). No circulation. Sensor fault.
Permanent Fault - Boiler reset in progress. Reset button has been pressed.
No or low system water pressure. Low system pressure (less than 0.5bar) boiler will not function.
Permanent Fault - On board CSU time-out. Check PCB for damage.
Permanent Fault - Permanent loss of communication between gas valve and boiler PCB. Fault in air/gas unit. Loose connection to gas valve.
Permanent Fault - Jumper 1 changed. Check position of jumper 1.
Permanent Fault - Jumper 2 changed. Check position of jumper 2.
Permanent Fault - Jumper 3 changed. Check position of jumper 3.
Permanent Fault - Connection to external device unsuccessful. Check wiring to external device.
Permanent Fault - Configuration to external device unsuccessful. Check pairing to external.
Permanent Fault - Gas valve fault. Gas valve not detected.
Permanent Fault - Flow temperature sensor short-circuited. Sensor not or badly connected. Bad connection. Sensor fault.
Permanent Fault - Flow temperature sensor open-circuited. Sensor not or badly connected. Bad connection. Sensor fault.
Permanent Fault - Critical flow temperature reached. Non-existent or insufficient circulation.
Permanent Fault - Flue temperature sensor short-circuited. Sensor not or badly connected. Bad connection. Sensor fault.
Permanent Fault - Flue temperature sensor open-circuited. Sensor not or badly connected. Bad connection. Sensor fault.
Permanent Fault - Critical flue gas temperature value reached. No circulation. Sensor fault.
Permanent Fault - Maximum safe temperature value reached. (Safety thermostat open-circuited). No circulation. Sensor not or badly connected. Bad connection. Sensor fault.
Failure to light (could be gas supply issue).
Permanent Fault - False flame signal. Short-term fluctuation of the mains. Ionization current present even though there is no flame. The burner remains very hot (CO2 too high). Defective gas/air unit.
Permanent Fault - Fan rotor blocked. Fan seized. Wiring to fan damaged.
Permanent Fault - Problem with gas valve. Defective gas/air unit.