BoilerFaultCodes.com

Vaillant ecoTEC plus Regular Fault Codes

Regular Natural GasLPG 12-35 kW 2012-present
GC Numbers: 41-044-6441-044-6541-044-6641-044-6741-044-68

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Most common fault codes

D,11
Your boiler is struggling to push hot water through your radiators because the external pump that circulates the water is not working correctly.
Gas Safe engineer required · £180-£350

All 1 fault code

Code Severity Plain English
D,11 High Your boiler is struggling to push hot water through your radiators because the external pump that circulates the water is not working correctly.

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.0 Diagnostic Your boiler is not running at its full heating capacity, meaning it may struggle to keep the house warm because it is stuck on a lower heat setting.
D.1 Diagnostic Your boiler is briefly keeping its internal pump running to safely move heat away from the system after it has finished warming your home.
D.2 Diagnostic Your boiler is taking a short rest to prevent it from switching on and off too frequently, which helps protect the internal components from unnecessary wear.
D.3 Diagnostic Your boiler is simply showing that it is currently preparing or providing hot water to your taps or cylinder.
D.4 Diagnostic Your boiler is displaying a status reading for the warm start sensor temperature rather than an error, which is part of the system's normal operational monitoring.
D.7 Diagnostic Your boiler is displaying a status message indicating the target temperature for the 'warm start' feature, which keeps water inside the unit pre-heated for faster hot water delivery.
D.8 Diagnostic Your boiler is working correctly and is simply indicating that your external thermostat or programmer is asking it to provide heat.
D.9 Diagnostic Your boiler is receiving a specific instruction from an external controller or thermostat telling it exactly what temperature to heat the water to.
D.10 Diagnostic Your boiler's internal pump, which moves water through your radiators, has encountered an electrical or mechanical fault and cannot circulate heat.
D.12 Diagnostic Your boiler is having trouble communicating with the pump that heats your hot water cylinder, meaning you might not have hot water.
D.13 Diagnostic There is a communication problem with the pump that circulates hot water, which usually means your hot water or heating might not work as expected.
D.17 Diagnostic Your boiler is switching from controlling the water temperature based on the outgoing flow to the returning water because it has detected a more stable reading that way.
D.18 Diagnostic Your boiler is currently set to run the pump continuously, which is usually a temporary setting used during maintenance or to prevent freezing.
D.19 Diagnostic Your boiler is currently running a check on its internal pump speeds to ensure it is circulating water as efficiently as possible.
D.20 Diagnostic Your boiler is notifying you that it has reached the maximum temperature allowed for your hot water cylinder.
D.22 Diagnostic This is a normal status message indicating that your boiler is currently working to heat up your hot water cylinder.
D.23 Diagnostic Your boiler is currently in summer mode, meaning it is only prioritising hot water and will not turn on the radiators.
D.25 Diagnostic Your boiler is simply letting you know that your external smart thermostat or system controller has successfully requested hot water.
D.27 Diagnostic Your boiler's internal control board is having trouble communicating with an add-on electrical component that manages your external pumps or heating zones.
D.28 Diagnostic Your boiler has detected a communication problem or a wiring fault with an external control accessory, such as an additional pump or zone valve.
D.30 Diagnostic Your boiler has detected an electrical issue with the parts that control the gas supply, preventing it from lighting safely.
D.33 Diagnostic Your boiler's fan is not reaching the correct speed required to safely clear exhaust gases, preventing the heater from starting up.
D.34 Diagnostic Your boiler is having trouble controlling the speed of its internal fan, which is preventing it from starting up safely.
D.36 Diagnostic Your boiler is having trouble measuring the flow of hot water, which could mean your taps don't get as hot as they should or your hot water fluctuates.
D.40 Diagnostic Your boiler is displaying its current target temperature and is working normally, as this is an information status code rather than a fault.
D.41 Diagnostic Your boiler is displaying the current temperature of the water returning from your radiators rather than indicating a specific fault.
D.44 Diagnostic Your boiler is having trouble managing its flame correctly and has shut down as a safety precaution.
D.47 Diagnostic Your boiler is struggling to accurately measure the temperature outside, which may cause your heating to be less efficient or run at the wrong temperature.
D.50 Diagnostic Your boiler is notifying you of a minor technical calibration adjustment regarding the fan's lowest operating speed.
D.51 Diagnostic Your boiler is signalling a setup issue related to the fan's speed range, meaning it is not operating at its intended maximum performance level.
D.58 Diagnostic Your boiler has paused its own water heating because it detects that your solar panels have already provided enough heat for your hot water cylinder.
D.60 Diagnostic Your boiler is repeatedly shutting itself down as a safety precaution because it is becoming too hot.
D.61 Diagnostic Your boiler is struggling to ignite and has reached its limit of failed attempts to start up.
D.64 Diagnostic Your boiler is taking longer than expected to light the flame, which is currently an advisory warning about its operation.
D.65 Diagnostic Your boiler is struggling to light its internal flame correctly, which might cause it to shut down for safety.
D.68 Diagnostic Your boiler is struggling to light its flame on the first try, which could cause it to lock out if it fails repeatedly.
D.69 Diagnostic Your boiler has failed to light the flame twice in a row, which means the system has stopped providing heating and hot water for safety.
D.70 Diagnostic Your boiler is currently stuck between modes and is trying to decide whether to send heat to your radiators or your hot water tank.
D.71 Diagnostic Your boiler is notifying you that its central heating temperature has been set to its maximum possible level.
D.72 Diagnostic Your boiler is continuing to run the pump for a short period to move heat away from the system after it has finished heating your water.
D.73 Diagnostic Your boiler is notifying you that it has adjusted the temperature settings for its pre-heat function to ensure hot water is ready when needed.
D.75 Diagnostic Your boiler has timed out because it has been trying to heat your hot water cylinder for too long without reaching the required temperature.
D.76 Diagnostic Your boiler is taking a temporary, normal breather to prevent the burner from turning on and off too quickly, which helps save energy and protect the components.
D.77 Diagnostic Your boiler is intentionally limiting the amount of power it uses to heat your hot water cylinder, which may result in your water taking longer to heat up than usual.
D.78 Diagnostic Your boiler is limiting the temperature it uses to heat your hot water tank to prevent it from getting too hot.
D.80 Diagnostic This is not a fault, but simply an informational status screen showing the total number of hours your boiler has spent in heating mode.
D.81 Diagnostic This is an advisory message showing you how many hours your boiler has spent heating your hot water cylinder.
D.82 Diagnostic Your boiler is currently preparing to fire up the burner to provide heating for your home and is not an actual error code.
D.83 Diagnostic Your boiler is notifying you that it has started heating up to provide hot water to your taps or cylinder.
D.84 Diagnostic Your boiler is simply reminding you that it is due for its routine annual service soon.
D.90 Diagnostic Your boiler is currently waiting for a signal from an external smart control or thermostat, meaning it is in a standby or communication phase rather than a fault.
D.91 Diagnostic Your boiler is providing a status update about its connection to an outdoor temperature sensor used for the radio clock signal.
D.93 Diagnostic Your boiler’s computer is confused about which specific model it is supposed to be, usually happening after a major part has been replaced.
D.96 Diagnostic Your boiler has lost its unique configuration settings and currently thinks it is a blank unit from the factory.
D.97 Diagnostic Your boiler is currently in an advanced settings mode used by engineers and does not indicate a mechanical fault with the heating system.
S.20 Status Your boiler is perfectly healthy and is simply letting you know that it is currently preparing or providing heat to your radiators or hot water cylinder.
S.21 Status Your boiler is performing a routine initial check of its internal air fan before it attempts to ignite the burner.
S.22 Status Your boiler is currently moving water through the system to prepare for heating or to cool itself down after use.
S.23 Status Your boiler is currently going through the normal steps to light the flame and start heating your home.
S.24 Status Your boiler is currently firing up and heating normally; this is a status update rather than a fault code.
S.25 Status Your boiler is busy prepping for a heating cycle by checking its internal sensors and clearing the flue, but if it stays stuck on this display, it may be failing to light.
S.26 Status Your boiler's internal cooling fan is staying on longer than expected after a heating cycle to ensure any remaining gases are cleared.
S.27 Status Your boiler is temporarily running the pump to circulate water and cool down the engine after it has finished heating.
S.28 Status Your boiler has temporarily paused to prevent it from turning on and off too frequently, which helps save energy and protect the internal components.
S.30 Status Your boiler is working fine, but your thermostat or external timer is not currently telling it to turn the heating on.
S.31 Status Your boiler is not providing heating because the central heating control knob on the front panel has been turned to the 'off' position.
S.32 Status Your boiler has paused to prevent itself from freezing because it has detected a problem with the fan speed, likely caused by a blocked or frozen flue pipe.
S.34 Status Your boiler has detected very cold temperatures and has automatically turned itself on to prevent the internal pipes from freezing.
S.36 Status Your boiler is currently waiting for a signal from your thermostat and isn't receiving a request to turn the heating on.
S.41 Status Your boiler has detected that the water pressure inside the system is too high, which could cause leaks or damage if not reduced.
S.42 Status Your boiler has stopped working because its internal safety system detected that wastewater cannot be pumped away or an add-on component is unresponsive.
S.53 Status Your boiler has temporarily stopped working because it cannot detect enough water flowing through the system to operate safely.
S.54 Status Your boiler has temporarily stopped working because it cannot detect enough water circulating through the system to operate safely.
S.96 Status Your boiler has detected an issue with the sensor that monitors water returning from your radiators, which may stop it from heating efficiently or starting up.
S.98 Status Your boiler is temporarily pausing because it has noticed an unusual temperature difference between two internal sensors and is performing a self-check to ensure everything is working correctly.

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