BoilerFaultCodes.com

Vaillant ecoTEC plus Fault Codes

CombiSystemRegular Natural GasLPG 12-38 kW 2005-present
GC Numbers: 47-044-3247-044-3347-044-3441-044-4841-044-4941-044-5041-044-5141-044-5247-044-5347-044-5447-044-5541-044-5841-044-5941-044-6041-044-6141-044-6247-044-8247-044-8347-044-8441-044-8541-044-8641-044-8741-044-8841-044-8947-044-9347-044-9447-044-9547-044-9641-044-7641-044-7741-044-7841-044-7941-044-80

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Most common fault codes

con
Your boiler's control panel and its internal computer are not talking to each other, meaning the unit cannot receive instructions to provide heat or hot water.
Gas Safe engineer required · £180-450
F.00
Your boiler has stopped working because it cannot communicate with the sensor that monitors the temperature of the water leaving the unit.
Gas Safe engineer required · £90-160
F.0
Your boiler has stopped working because it cannot accurately measure the temperature of the water leaving the unit due to a sensor or wiring connection fault.
Gas Safe engineer required · £100-£220

All 64 fault codes

Code Severity Plain English
con High Your boiler's control panel and its internal computer are not talking to each other, meaning the unit cannot receive instructions to provide heat or hot water.
F.00 High Your boiler has stopped working because it cannot communicate with the sensor that monitors the temperature of the water leaving the unit.
F.0 High Your boiler has stopped working because it cannot accurately measure the temperature of the water leaving the unit due to a sensor or wiring connection fault.
F.01 High Your boiler has stopped working because it cannot accurately measure the temperature of the water returning to the unit.
F.1 High Your boiler has stopped working because it cannot accurately measure the temperature of the water returning to the unit due to a faulty sensor or wiring.
F.10 High Your boiler has detected an electrical fault with the internal sensor that monitors the water temperature leaving the unit, causing it to shut down for safety.
F.11 High Your boiler has stopped working because it thinks the water returning to the unit is much hotter than it actually is, causing it to shut down for safety.
F.12 High Your boiler has lost the ability to measure the temperature of your hot water cylinder because of a faulty sensor or a wiring issue, meaning it cannot heat your water correctly.
F.13 Medium Your boiler has detected an electrical fault with the sensor that monitors your hot water tank, meaning it cannot accurately tell if your water is hot enough.
F.20 High Your boiler has switched itself off because it has reached an unsafe temperature and needs to cool down.
F.22 High Your boiler has stopped working because the water pressure inside the system has dropped too low to operate safely.
F.23 High Your boiler has shut down because there is a significant difference between the water temperature leaving the boiler and the temperature returning to it, usually caused by a circulation problem.
F.24 High Your boiler has shut down because the internal water temperature is heating up much faster than it can be circulated away, usually meaning the water is stuck or the pump is struggling.
F.25 Emergency Your boiler has shut itself down because the air being pushed out of the chimney pipe has become dangerously hot.
F.27 High Your boiler has sensed a flame when there shouldn't be one, so it has shut down as a safety precaution to prevent damage.
F.28 High Your boiler is trying to light itself to provide heat, but it is failing to create a flame, likely because it is not getting enough gas or the spark isn't catching.
F.29 High Your boiler was working but the flame went out and it cannot manage to light itself back up.
F.32 High Your boiler's fan is unable to spin at the correct speed, which prevents the boiler from safely clearing exhaust fumes and starting the ignition process.
F.49 High Your boiler has lost its ability to communicate with its external controls, such as your thermostat, due to an electrical glitch in the internal data wiring.
F.61 High Your boiler is unable to correctly control the flow of gas, causing it to shut down for safety purposes.
F.62 Emergency Your boiler has detected that the gas valve is not closing as quickly as it should, preventing the unit from shutting down the burner safely.
F.63 High Your boiler's internal computer brain is having trouble reading its memory, causing the system to stop working for safety.
F.64 High Your boiler has detected an internal communication error between its electrical sensors and the main control board, causing it to shut down for safety.
F.65 High Your boiler's internal control board has become too hot and has shut down the system to prevent damage.
F.67 High Your boiler's electronic control board has detected a confusing signal from the flame sensor, causing the system to shut down for safety.
F.68 High Your boiler is struggling to keep its flame burning steadily, causing it to shut down for safety.
F.70 High Your boiler’s control board has lost its identity settings, meaning the internal computer no longer knows which specific model it is supposed to be operating.
F.71 High Your boiler is struggling to accurately measure the water temperature leaving the unit, usually because a sensor has failed or become disconnected.
F.72 High Your boiler has detected that the sensors measuring water temperature going in and out are giving conflicting readings, so it has shut down as a safety precaution.
F.73 High Your boiler is struggling to read how much water is in the system because of a sensor issue, which has caused it to stop working for your safety.
F.74 High Your boiler's internal sensor has detected that the water pressure is too high or the sensor itself is sending an incorrect reading.
F.75 High Your boiler is unable to sense water moving or pressure building when it tries to start up, which has caused it to shut down for safety.
F.76 High Your boiler's safety sensor has detected that the main heating component is getting too hot, so the system has shut itself down to prevent damage.
F.77 High Your boiler is struggling to push waste gases out through the flue or is unable to clear internal condensation water properly.
F.78 High Your boiler is having trouble communicating with an external hot water control component, meaning it doesn't know the temperature of the water heading to your taps.
F.83 High Your boiler is firing up, but it doesn't detect the water getting hotter quickly enough, so it has shut down to prevent itself from overheating.
F.84 High Your boiler is confused because its internal thermometers are giving conflicting readings and don't agree on how hot the water actually is.
F.85 High Your boiler has stopped working because its internal thermometers are giving conflicting readings and believe they have been fitted to the wrong pipes.
F.86 High Your boiler has stopped providing heat because a safety limit switch for your underfloor heating has been triggered or disconnected.
F.87 High Your boiler has detected a problem with the internal ignition components, meaning it cannot safely light the burner to provide heat or hot water.
F.88 High Your boiler has detected an electrical connection issue with the gas valve, meaning it cannot safely ignite to provide heating or hot water.
F.89 High Your boiler's main internal pump is not speaking correctly to the control board, preventing the system from circulating heat.
F.91 High Your boiler has lost the ability to monitor the water temperature in your hot water cylinder due to an electrical connection fault.
F.92 High Your boiler's internal computer is receiving the wrong information about its own identity, preventing it from running safely.
F.97 High Your boiler's internal computer has failed a self-test and is no longer able to communicate with the rest of the system.
F.XX-F.XX Low This code isn't an active fault but rather a menu view showing the history of past errors your boiler has experienced.
F70 High Your boiler's computer brains are not talking to each other correctly because a security code needs to be re-entered after a repair.
P.00 Low Your boiler is currently running an automatic program to remove trapped air from the system, which usually happens during startup or after maintenance.
P.0 Low Your boiler is currently running a self-cleaning routine to remove trapped air bubbles from the system.
P.01 Medium Your boiler has failed while running a specific test used for commissioning or high-power performance checks.
P.1 Low Your boiler is simply running a routine internal test to check it can operate at its maximum power level after starting up.
P.02 Low Your boiler is not in a fault state; it is simply running a pre-programmed test to check how it performs at its lowest power setting.
P.2 Low Your boiler is currently running a background self-test to check it can operate safely at its lowest power setting.
P.3 Low Your boiler is undergoing a temporary calibration process where it checks its heating settings; it is not a fault, but a normal status message.
P.4 Low Your boiler is currently running a safety program to remove trapped air from the internal pipes and heat exchanger.
P.5 Low Your boiler is running a specialized internal test to ensure its safety sensor correctly shuts the system down if it gets too hot.
P.06 Low Your boiler is currently running a self-check program to fill the heating system with water and is not experiencing a permanent fault.
P.6 Low Your boiler is currently running a self-diagnostic test to check the water pressure and fill level as it prepares to start up.
T.02 High Your boiler is struggling to switch between providing hot water and heating your radiators because an internal valve is stuck or malfunctioning.
T.03 High Your boiler's fan is struggling to start or run at the correct speed, which is preventing the boiler from firing up for safety.
T.04 High Your boiler is struggling to move heated water to your hot water cylinder, which means you may not have any hot water.
T.05 High Your boiler's internal pump is having trouble moving water through the system, which is preventing it from providing heating or hot water.
T.06 High Your boiler is struggling to push water around your radiators because an external pump is not working as expected.
T.08 Low Your boiler is currently completing a routine check of its burner system while it is in the process of starting up.

Status & diagnostic codes

These codes indicate your boiler's operating state or a diagnostic reading — not necessarily a fault. Status codes (S.) mean normal operation; diagnostic codes (D.) are informational readings used by engineers.

Code Type Description
D.000 Diagnostic Your boiler is currently set to run at a lower power level than its maximum capacity to save energy or match your home's heat demand.
d.18 Diagnostic Your boiler is simply showing its current pump setting status rather than a fault; it indicates whether the pump is running constantly or only when needed.
S.0 Status Your boiler is working perfectly fine and is simply in standby mode because your thermostat is not currently asking for the heating to be turned on.
S.01 Status Your boiler is performing a normal startup procedure by clearing out the combustion chamber before it begins heating your home.
S.1 Status Your boiler is preparing to ignite but is stuck at the stage where the internal fan is spinning up to clear the combustion chamber.
S.02 Status Your boiler is simply preparing its internal pump before starting the heating process, which is a normal part of its operation.
S.2 Status Your boiler is currently moving water through the system after a heating or hot water cycle to cool down the internal components safely.
S.03 Status Your boiler is currently busy performing its normal start-up sequence to fire up the burner for heating.
S.3 Status Your boiler is currently trying to light the flame to start provide heating or hot water, and this is a normal status message rather than a permanent error.
S.04 Status Your boiler is currently working perfectly and is simply telling you that it is busy heating your radiators.
S.4 Status Your boiler is operating normally and is currently in the process of starting up the burner to provide heat or hot water.
S.05 Status Your boiler is briefly keeping the internal fan and pump running to safely cool down the heat exchanger after a heating cycle.
S.5 Status Your boiler is pausing during its startup sequence while it waits for a signal that the fire has safely lit.
S.06 Status Your boiler is temporarily running the internal fan to cool the system down after the heating has switched off.
S.6 Status Your boiler's fan is continuing to run for longer than expected after the heating or hot water has finished.
S.07 Status Your boiler is briefly running the pump after heating your radiators to safely move residual heat away from the unit.
S.7 Status Your boiler is briefly keeping the internal pump running to safely circulate and dissipate leftover heat after you have finished using your heating or hot water.
S.08 Status Your boiler is taking a short, normal break after finishing a heating cycle to prevent overheating and ensure everything cools down properly.
S.8 Status Your boiler has reached the correct temperature and is taking a short, planned break to prevent it from switching on and off too frequently.
S.20 Status Your boiler is not broken; it is simply letting you know that it has received a request to provide hot water and is currently preparing to deliver it.
S.21 Status Your boiler is briefly checking its fan and clearing the system before it starts heating your hot water.
S.22 Status Your boiler is not broken; it is simply performing a routine preparation step to ensure everything is ready before it begins heating your water.
S.23 Status Your boiler is currently preparing the burner to provide hot water, which is a normal part of its operation.
S.24 Status Your boiler is working normally and is currently heating up your hot water.
S.25 Status Your boiler is briefly cooling itself down after providing hot water and will resume normal operation in a few moments.
S.26 Status Your boiler is simply running its internal fan for a short period to cool down after you have finished using hot water.
S.27 Status Your boiler is briefly running the internal pump after providing hot water to help cool down the internal components.
S.28 Status Your boiler has temporarily stopped the burner because it has reached the required temperature for hot water and is taking a short break to prevent overheating.
S.30 Status Your boiler is working fine, but your external room thermostat or timer is telling it not to turn the heating on right now.
S.31 Status Your boiler is working correctly but is currently ignoring heating requests because it is either set to summer mode or is waiting for a command from your external thermostat.
S.32 Status Your boiler is struggling to start because the internal fan is not spinning at the correct speed required for a safe ignition.
S.34 Status Your boiler has sensed the temperature is very cold and is automatically running to prevent the internal pipes from freezing.
S.36 Status Your boiler is working fine, but your external thermostat or heating controls aren't telling it to turn on.
S.39 Status Your boiler has received a signal from your underfloor heating system to stop running, likely because a safety thermostat has triggered to prevent the floor from getting too hot.
S.41 Status Your boiler has detected that there is too much water in the system, which puts extra stress on the pipes and components.
S.42 Status Your boiler has detected that a safety flap in the flue pipe is stuck closed, preventing exhaust gases from escaping.
S.46 Status Your boiler has detected very cold temperatures and has automatically turned itself on at a low setting to prevent the internal pipes from freezing.
S.53 Status Your boiler has temporarily stopped working because it has detected that water is the not moving through the system quickly enough to safely carry heat away.
S.54 Status Your boiler has paused because it detects that water is not circulating quickly enough, often due to low pressure or an air pocket.
S.88 Status Your boiler is currently running an automatic program to clear air bubbles out of the internal pipework and does not require a repair.
S.91 Status Your boiler is currently set to a 'showroom' mode which allows the display to work for demonstration purposes but prevents the burner from actually firing to provide heating or hot water.
S.96 Status Your boiler is temporarily paused because it is running a self-diagnostic check on its internal temperature sensors to ensure they are working correctly.
S.98 Status Your boiler is temporarily paused because it has detected a potential issue with its internal sensors while performing a self-test.
S.99 Status Your boiler is temporarily running a self-diagnostic check to ensure everything is working correctly and will resume normal operation shortly.
S.108 Status Your boiler is currently performing a routine self-cleaning cycle to clear any fumes from the system before it attempts to ignite.
S.109 Status Your boiler has temporarily stopped working because it has entered a standby mode, usually while it waits for a signal from your thermostat or because it needs to take a short break before restarting.

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