Vaillant ecoTEC Plus 836 Fault codes & diagnostics

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.

Your boiler has lost the ability to read the temperature of the water inside it, so it has shut down as a precaution to prevent overheating.

Your boiler has lost its connection to a sensor that measures the temperature of water returning to it, meaning it cannot safely regulate how much it heats your home.

Your boiler is struggling to detect the temperature of your hot water supply because of a faulty connection or sensor, which will likely prevent you from getting hot water.

Your boiler has lost its connection to the sensor that measures water temperature, so it has safely shut down to prevent overheating.

Your boiler has lost its connection to a sensor that measures the temperature of the water coming back into the system, which is preventing it from running safely.

Your boiler is struggling to accurately measure the temperature of the water it is heating for your taps, meaning you likely have no hot water available.

Your boiler has detected that the water pressure inside the system has dropped too low, so it has safely shut itself down to prevent any damage.

Your boiler has stopped working because the water pressure inside the system has dropped too low to operate safely.

Your boiler is struggling because there is trapped air or a blockage preventing water from circulating properly around your heating system.

Your boiler has detected trapped air inside the system, which is causing the water temperature to rise much faster than it safely should.

Your boiler has detected that the exhaust gases are getting much hotter than they should be, or there is an issue with the electrical connection monitoring these temperatures.

Your boiler is failing to light because it cannot detect a flame, meaning you currently have no heating or hot water.

Your boiler has stopped working because it cannot detect a flame, most likely because it is not receiving enough gas to stay lit.

Your boiler has detected that the internal fan responsible for venting exhaust gases safely is not spinning at the correct speed, so it has shut down to prevent unsafe operation.

Your boiler has lost the electrical connection to the part that manages the gas supply, meaning it cannot safely start up and will stop providing heat and hot water.

Your boiler's communication system, which allows it to talk to your thermostat and other controls, is currently experiencing a wiring fault or a connection conflict.

Your boiler has detected a failure in its internal combustion safety system and has shut down to prevent unsafe operation.

Your boiler has detected an internal communication error with the gas control system, which prevents it from safely igniting the burner.

Your boiler's main control computer is experiencing a memory error and can no longer process instructions correctly, meaning the unit will not be able to operate.

Your boiler's electronic control system is unable to read data from one of its internal sensors, causing it to shut down for safety reasons.

Your boiler has detected that its internal computer is getting too hot and has shut itself down to prevent damage to the internal wiring and controls.

Your boiler is confused because it detects a flame when it shouldn't be there, or the sensor that checks for the flame is malfunctioning.

Your boiler's main control unit is struggling to correctly detect or manage the burner flame, meaning it will likely shut down to keep you safe.

Your boiler's computer needs a specific digital code to recognise the new parts that were recently installed.

Your boiler is struggling to read its own internal water temperature accurately, so it has stopped working to prevent any potential damage.

Your boiler has detected that the water temperature readings are inconsistent, which stops it from heating your home safely.

Your boiler is struggling to read how much water is inside the system because the sensor that monitors pressure has lost its electrical connection.

Your boiler is struggling to confirm that water is flowing correctly through the system because a sensor is failing to detect the expected pressure change.

Your boiler has detected that a safety sensor meant to prevent overheating has lost its connection, so it has safely shut down to prevent damage.

Your boiler has detected an issue with the exhaust system that prevents it from safely venting gases, so it has stopped working to protect you.

Your boiler has detected that an electronic component inside the unit is not the correct model or version required for this specific system.

Your boiler has lost the internal electrical connection needed to heat your hot water tank, meaning you likely have no hot water available.

Your boiler is failing to heat up because it cannot detect any water movement or temperature change, which usually indicates that your system pressure has dropped too low.

Your boiler is confused because it is detecting unusual temperature differences between its water pipes, which usually means a sensor is loose, incorrectly fitted, or malfunctioning.

Your boiler's temperature sensors have been swapped or attached to the wrong pipes, meaning the boiler cannot accurately measure how hot the water is.

Your boiler is failing to light because the component responsible for creating the ignition spark is not receiving power or is incorrectly plugged in.

Your boiler has detected that the internal water pump is not the correct type for this specific model, which prevents it from operating correctly.

Your boiler has lost the electronic connection to your hot water tank, meaning it cannot detect or manage your hot water supply.

Your boiler has not been correctly set up to handle the specific type of gas it is receiving, preventing it from operating safely.

Your boiler's internal computer has failed its diagnostic check, meaning it cannot safely control the system.

Your boiler's computer has lost the specific internal calibration settings required to mix the gas and air correctly for combustion.

Your boiler has detected an internal electrical failure which is preventing it from powering up correctly, meaning it cannot provide heating or hot water.

Your boiler is struggling because it is not receiving enough electricity from your home's mains power supply.

Your boiler has detected an unstable electricity supply that is higher than the safe limit, causing it to shut down to protect its internal electronics.

Your boiler is struggling to switch between heating your radiators and heating your hot water because the internal valve that directs the water flow is not receiving an electrical signal.

Your boiler's water pump is struggling to circulate water because it is blocked by debris or sludge, which will prevent your heating and hot water from working.

Your boiler's water circulation pump has stopped working, which means the system cannot push hot water to your radiators or taps.

Your boiler's water pump has detected it is getting too hot and has automatically shut down to prevent damage.

Your boiler has trapped air inside its main water circulation system, which is preventing the pump from moving water effectively to provide heat or hot water.

Your boiler has lost its connection to the internal water pump, which means it cannot circulate water to provide you with heating or hot water.

Your boiler is unable to move water around your heating system because the internal pump is stuck or not spinning correctly.

Your boiler is struggling to switch between heating your radiators and heating your hot water because a key internal valve is stuck or failing.

Your boiler has detected that the water pump, which is essential for circulating heat around your home, is failing to start correctly.

Your boiler's computer system has lost the specific settings that tell it how your exhaust pipe is configured, preventing it from starting up safely.

Your boiler has detected that the air intake or exhaust setup does not match its internal settings, meaning it cannot operate safely and has shut down to prevent damage.

Your boiler has detected that the flue attachment used to vent exhaust gases does not correctly match the internal configuration of your specific heater model.

Your boiler's internal settings do not match the way it is connected to its flue pipe, causing it to stop working to prevent unsafe operation.

Your boiler is struggling to push the right amount of air through its system to burn gas safely, so it has stopped working to prevent any potential danger.

Your boiler has lost the connection to the internal sensor that measures the air flow needed for safe combustion, causing the unit to stop working as a precaution.

Your boiler has lost the digital settings it needs to safely control the flame, meaning it cannot operate until these are reset or the internal hardware is replaced.

Your boiler has detected water pooling inside the internal combustion area, which prevents it from firing up safely to protect the system.

Your boiler's computer screen or main control board is having trouble saving and reading its internal settings, which means the boiler cannot safely operate.

Your boiler's control panel has lost its connection to the internal brain, meaning the system cannot communicate or operate safely.

Your boiler has detected an electrical fault in its internal communication system, causing it to shut down to prevent further damage.

Your boiler has lost its flame while running at a low heat setting, causing it to shut down for safety.

Your boiler has detected that there is not enough water flowing through the heating system to operate safely.

Your boiler is struggling to accurately detect the flow of water circulating through your heating system, which means it may prevent the heating or hot water from turning on to protect itself.

Your boiler's gas control mechanism is struggling to adjust correctly, meaning it cannot reliably maintain the flame required to heat your home.

Your boiler has detected an issue with the internal gas control mechanism, preventing it from starting up safely.

Your boiler is struggling to remove trapped air from the system, which is preventing it from starting up correctly.

Your boiler is struggling to detect the flame needed to heat your water and home, so it has shut down as a safety precaution.

Your boiler's main control system has detected a power failure on its internal circuit board, meaning it cannot operate safely and has shut down.

Your boiler has detected an unstable or too-high electrical voltage coming from your home's mains power supply, causing it to shut down to protect its internal electronics.

Your boiler's water pump is struggling to spin, likely due to debris or inactivity, so the system is currently trying to clear itself to get your heating and hot water back on.

Your boiler has detected that the water circulation pump is getting too hot and has stopped working to protect itself, which means you currently have no heating or hot water.

Your boiler has detected an issue with how it measures the amount of air flowing through its internal system, which prevents it from operating safely.

Your boiler is struggling to detect the flow of water because of trapped air or a faulty sensor, meaning it cannot reliably heat your home or water.

Your boiler has identified that the internal water pump currently installed is the wrong model for your specific heater, preventing it from starting up correctly.

Your boiler is struggling to receive enough gas to heat your home properly and has reached its safety limit trying to compensate.

Your boiler's main electronic control board is failing to receive the power it needs to function, which means the system cannot operate.

Your boiler is struggling to circulate water properly because an internal valve is blocked with debris, which may stop your heating or hot water from working effectively.

Your boiler has lost its connection to the water pump, which means it cannot circulate water to provide you with heating or hot water.

Your boiler's air sensor is disconnected or faulty, which prevents it from correctly measuring the air flow needed to burn fuel safely.