Vaillant Boiler Fault Codes
Vaillant Boiler Fault Codes
F.00 - NTC Faults
Faults with the NTC thermistor, which provides temperature readings to the boiler's control system.
F.10, F.11, F.12, F.13, F.14 - Ignition Problems
Failure to ignite. This could be due to a problem with the boiler's ignition, gas supply or a blocked condensate pipe.
F.20 - Safety Switch Off: Low-Water Content
The boiler has shut off due to low water pressure.
F.22 - Dry Fire, Low Water Pressure
The boiler pressure is too low and needs to be repressurised.
F.23 - Safety Switch Off: Temperature Limiter
The boiler has become too hot.
F.24, F.37 - Fault: Water Shortage
The boiler has detected a lack of water in the system.
F.27 - Mains Undervoltage
An issue with the voltage supply.
F.28, F.29 - Failure During Start-Up: Ignition Fault
The boiler has failed to ignite.
F.32 - Fan Speed Variance: Fan Running Too Slow
The boiler's fan is running too slow.
F.49 - eBUS Under Voltage
This indicates a fault with the power supply.
F.61, F.62, F.63, F.64, F.65 - Electronic Faults
These indicate various electronic faults within the boiler.
F.67 - Fluctuation in Mains Voltage
The mains electrical supply to the boiler is fluctuating.
F.70 - Unrecognisable Configuration
This suggests that there's an issue with the configuration of the boiler's settings.
F.71 - Flow NTC Open Circuit
There is a problem with the NTC sensor in the boiler.
F.72 - Flow/Water Pressure
The boiler is experiencing water pressure issues.
F.74 - Flow and Return Sensors
The flow and return sensors are reporting different readings.
F.75 - Pump or Water Shortage
The pump isn't working correctly or there's a lack of water in the system.
F.76 - Overheating Boiler, Heat Exchanger
The boiler or heat exchanger is overheating.
F.77 - Flue or Heat Exchanger Overheating
The flue or heat exchanger is overheating.
F.78 - Flue or Return Sensor Contact
There's a problem with the contact between the flue and the return sensor.
F.83 - Fault in Electronic Main Control
There's an issue with the electronic main control of the boiler.
F.84 - Flow Sensor Contact Fault
The flow sensor has a contact fault.
F.85 - Flow Sensor Fault
The flow sensor is not working correctly.
F.86 - Return Sensor Fault
The return sensor is not working correctly.
F.92 - Coding Resistor Fault
The coding resistor has a fault.
F.93 - Incorrect Configuration Coding
The configuration coding of the boiler is incorrect.
F.94 - Configuration Fault: Gas Family
The boiler's gas family configuration is incorrect.
F.95 - Configuration Fault: Gas Type
The boiler's gas type configuration is incorrect.
F.96 - Configuration Fault: Gas Controller
There's an issue with the configuration of the boiler's gas controller.
F.97 - Configuration Fault: Gas Quality
The boiler's gas quality configuration is incorrect.
F.98 - Configuration Fault: Flue Gas Configuration
There's an issue with the configuration of the boiler's flue gas.
F.99 - System Fault: External
There's an external system fault.
F.A1 - Pump Stuck or Running with Water Shortage
The pump is either stuck or running without enough water.
F.A2 - Pump Overloaded
The pump is overloaded.
F.A3 - Hot Water NTC Open Circuit
There's an open circuit in the hot water NTC
F.A4 - Hot Water NTC Short Circuit
There's a short circuit in the hot water NTC.
F.A5 - Tank NTC Open Circuit
There's an open circuit in the tank NTC.
F.A6 - Tank NTC Short Circuit
There's a short circuit in the tank NTC.
F.A7 - Hot Water NTC Sensor Fault
There's a fault with the hot water NTC sensor.
F.A8 - Break in Communication with IDM
There's been a break in communication with the IDM.
F.A9 - Tank or No Hot Water
There's either an issue with the tank or no hot water.
F.C0 - Unconfigured PCB
The PCB has not been configured properly.
F.C1 - PCB Error
There's an error with the PCB.
F.C7 - Incorrect Flame
The boiler has detected an incorrect flame.
F.d.0, F.d.1, F.d.8 - Service Functions
These codes relate to service functions of the boiler.
Are you interested in replacing your boiler and avoiding recurrent Vaillant Boiler Fault Codes and problems?
As a reliable and experienced plumbing and heating service provider, Xbg Plumbing & Heating has a team of dedicated professionals who are committed to consistently providing high-quality services to our clients.
Don’t let plumbing or heating problems cause stress and inconvenience in your life. Trust the experts at Xbg Plumbing & Heating to provide you with the solutions you need. Contact us today to schedule a consultation or request a quote!
Does my boiler need to be replaced?
We believe in an transparent and honest approach with all our customers, so will always give you the best advice if your boiler needs replacing. There can be a variety of different reasons that will help identify that your boiler may need replacing. The pilot on your pilot light should burn blue, in the event that’s it’s a different colour, then please call us right away.
Additionally, if you notice strange noises from either the boiler or radiators. You may suddenly hear an increase in noise level, this indicates a problem and needs attention by a qualified gas engineer. Finally, and just as important as the other points, any evidence of any leaks or strange smells coming from your boiler, should be treated as urgent. Please call us 01903 536 502, so we can advise you on the next steps.
Boiler Types Explained
Combi boiler
A combination or ‘combi’ boiler is both a high efficiency water heater and a central heating boiler in a single compact unit. Combi boilers heat water directly from the mains when you turn on a tap, so you won’t need a hot water storage cylinder or a cold water storage tank in the roof space.
They are also very cost-effective and energy-efficient as water is heated instantly rather than being heated and then stored in a cylinder. An added benefit is that hot water is delivered at mains pressure, which means that you could get a powerful shower without the need for a separate pump.
System boiler
System boilers require a cylinder for storing hot water, however the major heating and hot water system components are built into the boiler itself, making it quicker and easier to install. In addition, there is no need for a tank in the loft, so it can be an option in a home with little or no loft space or where the space is earmarked for a conversion.
These boilers are also compatible with solar water heating systems, which deliver environmental benefits as well as lower energy bills.
Regular boiler
Regular boilers (sometimes known as traditional, conventional or heat only boilers) are ideally suited to homes that already have a traditional heating and hot water system which is linked to a separate hot water cylinder. These boilers also need a cold water storage tank in the loft to feed the hot water cylinder as well as a tank that maintains the water level of the central heating system.
A regular boiler may be the best option for replacing an existing boiler if the property has an older radiator system, as it might not be able to cope with the higher water pressure that is delivered by system or combi boilers
