BoilerFaultCodes.com

Vaillant ecoTEC Fault Codes

CombiSystemRegular Natural GasLPG 12-38 kW 2005-present

All 60 fault codes

Code Severity Plain English
D,11 High Your boiler is struggling to push hot water around your radiators because an external pump is not responding correctly.
D.0 Low Your boiler is currently restricted to a lower power setting for heating, meaning your radiators might take longer to warm up or may not get as hot as they should.
D.1 Low Your boiler is not broken; it is simply continuing to run the internal pump for a few minutes to safely cool down the heat exchanger after providing heating or hot water.
D.2 Low Your boiler is temporarily resting because it has reached its target temperature and is waiting for a short period before restarting to prevent unnecessary wear and tear.
D.3 Low Your boiler is currently showing you the live temperature of the hot water it is producing, which is a normal status message rather than an error.
D.4 Low Your boiler is currently showing the live temperature reading of the sensor responsible for keeping your hot water pre-heated.
D.5 Low Your boiler is displaying a status message to show the temperature it is currently trying to reach for your heating or hot water, rather than being a functional fault code.
D.7 Low Your boiler is displaying an information code to show that the pre-heated water feature for your taps is currently active.
D.8 Low Your boiler is receiving a signal from your thermostat or external controls asking for heat, and it is operating as it should.
D.9 Low Your boiler is receiving a instruction to heat water to a specific temperature from an external thermostat or smart heating control.
D.10 High Your boiler's internal pump is having trouble circulating water through the system, which is preventing your heating from working.
D.12 High Your boiler is having trouble communicating with the pump that heats your hot water cylinder, meaning you may experience a lack of hot water.
D.13 High Your boiler is having trouble moving hot water through the internal pipes, which usually means the circulation pump cannot start or is stuck.
D.14 Medium Your boiler is struggling to control the speed of its internal pump, meaning water may not be circulating through your radiators efficiently.
D.15 Low Your boiler is displaying an information code because the pump that moves water around your pipes is spinning at a different speed than expected.
D.17 Low Your boiler has switched its control method to the return pipe because it is detecting a potential issue with the main flow sensor.
D.18 Low Your boiler is currently set to run the pump continuously, which is usually a configuration setting rather than a breakdown.
D.20 Low Your boiler has reached the maximum allowed temperature for heating your hot water cylinder and is pausing operation as a standard safety limit.
D.22 Low Your boiler is currently providing hot water to your taps or shower, which is a normal status message rather than an actual fault.
D.23 Low Your boiler is currently set to summer mode, which means it is only heating your tap water and has temporarily turned off the central heating.
D.24 Medium Your boiler is struggling with water flow, likely due to a build-up of debris or air in the system which is preventing the heat from circulating properly.
D.25 Low Your boiler is currently busy heating your hot water because your smart thermostat or external controller has told it to do so.
D.26 High Your boiler's internal control board is unable to communicate with an optional secondary accessory or pump, causing the system to stop running as a safety precaution.
D.27 Medium Your boiler's internal control board is having trouble communicating with an external part or accessory, which may prevent the system from starting up correctly.
D.28 Medium Your boiler is having trouble communicating with an external control or smart home accessory, which might prevent your heating or hot water from turning on correctly.
D.30 High Your boiler is struggling to send the correct message to its gas supply valves, which usually means it cannot light safely.
D.33 Medium Your boiler is struggling to match the correct fan speed needed to safely clear exhaust gases, which may lead to the system pausing for safety.
D.34 High Your boiler is struggling to accurately measure how fast its internal fan is spinning, which is preventing the system from heating correctly.
D.35 Low Your boiler is currently switching over between its heating and hot water functions.
D.40 Low Your boiler is displaying the temperature it is currently aiming for rather than a fault, which is a normal status message and not a breakdown.
D.41 Low Your boiler is displaying the current temperature of the water returning from your radiators rather than indicating a fault.
D.44 Medium Your boiler's electronic system is struggling to correctly detect the flame signal, which could lead to it locking out for safety.
D.47 Low Your boiler's outside temperature sensor is either giving an incorrect reading or has lost communication with the main control system.
D.50 Low This is a technical status message indicating the boiler is adjusting its fan speed settings and is not usually a hardware fault.
D.51 Low Your boiler is flagging a minor technical adjustment error regarding its internal fan speed settings.
D.60 High Your boiler has shut down multiple times because it reached a dangerously high temperature and is recording how often this safety limit has been triggered.
D.61 High Your boiler is recording that it has repeatedly failed to light or stay on, leading to multiple safety shutdowns.
D.64 Low Your boiler is taking longer than usual to light, though it is still currently working.
D.65 High Your boiler is struggling to spark or light the gas correctly, which is a safety mechanism preventing it from trying to ignite for too long.
D.67 Low Your boiler is simply taking a short, programmed break between heating cycles to protect its internal parts and operate more efficiently.
D.68 Medium Your boiler is struggling to light its flame on the first try, though it may eventually start after several attempts.
D.69 High Your boiler has failed to light the flame twice in a row, which means the system has stopped working for your safety.
D.70 Low Your boiler is currently stuck in a diagnostic test mode that overrides its normal settings, which usually happens during a service or repair.
D.71 Low Your boiler is currently set to run at its maximum possible heating temperature, meaning it is working as hard as it can to heat your radiators.
D.72 Low Your boiler is continuing to run its internal pump for a short period after heating your water to ensure it cools down safely and efficiently.
D.75 Medium Your boiler is taking longer than expected to heat up your hot water tank, causing the system to stop as a precaution.
D.76 Low Your boiler is taking a short, programmed break to prevent itself from turning on and off too frequently, which protects the internal components from unnecessary wear.
D.77 Low Your boiler is temporarily reducing its power while heating your hot water cylinder because it is reaching its temperature limit too quickly.
D.78 Low Your boiler is limiting the temperature of the water being sent to your hot water cylinder, which typically means the water won't get as hot as usual.
D.80 Low This is not a fault; it is simply a diagnostic screen displaying how many hours your boiler has spent running the central heating.
D.81 Low This is an information code rather than a fault, showing you the total number of hours your boiler has spent heating up your water.
D.82 Low Your boiler is currently checking its systems and preparing to fire up the burner to provide central heating.
D.83 Low Your boiler is providing a status update to show it is currently heating up the water for your taps.
D.84 Low Your boiler is simply letting you know that it is due for its routine annual service soon.
D.90 Low Your boiler is currently waiting for the digital control system to finish communicating, which usually means it is temporarily busy rather than broken.
D.91 Low Your boiler is checking for a radio signal to automatically set the time and date using an outdoor weather sensor.
D.93 High Your boiler's internal computer has lost its identity settings and doesn't know which specific model it is supposed to be.
D.96 High Your boiler has reverted to its original factory settings and needs its specific configuration data entered to work correctly with your heating system.
D.97 Low Your boiler is currently showing a hidden menu used by engineers for advanced system analysis, but it does not represent an actual mechanical fault.
D.98 Low This is a prompt or status message indicating that the boiler requires professional maintenance or has reached a specific service interval that needs an engineer's attention.

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