Atag Q 25S Fault codes & diagnostics

Your boiler is struggling to light or stay lit properly, meaning it cannot produce heat or hot water reliably.

Your boiler has detected an electrical fault in its low-voltage control system, causing it to shut down to prevent damage.

Your boiler has attempted to start but is unable to ignite a flame, meaning it cannot produce any heat or hot water.

Your boiler has detected an issue with its internal settings or configuration that prevents it from starting correctly.

Your boiler has lost its internal electrical power supply, which means it will stop working until the protection fuse is replaced.

Your boiler has detected that the water inside the system has become dangerously hot and has shut itself down to prevent damage.

Your boiler has detected that the water returning to it from your radiators is getting too hot, so it has shut itself down to prevent damage.

Your boiler's internal fan is failing to communicate with the control board, meaning the system cannot safely vent exhaust gases and will not start.

Your boiler's screen is blank or showing incorrect information, meaning the system's control brain cannot communicate with you or function correctly.

Your boiler has stopped working because it cannot detect the safety sensor that monitors the temperature of the exhaust fumes.

Your boiler has detected a faulty reading from the internal temperature sensor for the exhaust system and has shut down to keep itself safe.

Your boiler’s internal computer has lost the correct settings for how much power it should use, causing it to stop working to protect itself.

Your boiler has automatically paused its operation because the exhaust fumes inside the unit have become too hot, and it will try to start again once it has cooled down sufficiently.

Your boiler has detected that a key safety sensor measuring exhaust gases has become unplugged, so it has safely shut itself down to prevent operation.

Your boiler has detected a faulty sensor reading in the exhaust system and has safely shut down to prevent incorrect operation.

Your boiler is failing to light the internal flame needed to produce heat and hot water.

Your boiler has detected an electrical fault in its internal control system that is preventing it from operating safely.

Your boiler is failing to light the internal burner, meaning it cannot produce any heat or hot water.

Your boiler has detected an issue with its power supply or an internal electrical signal fluctuation, which has caused it to stop working for safety reasons.

Your boiler is having difficulty correctly adjusting its internal gas and air settings to run efficiently.

Your boiler has stopped working because a protective electrical fuse inside the main control board has blown, preventing the system from powering up safely.

Your boiler has detected that the water inside the system has become dangerously hot and has shut itself down to prevent damage.

Your boiler has detected that the water returning from your radiators is getting too hot, so it has shut itself down to prevent any damage.

Your boiler is unable to confirm that the internal fan is spinning correctly, so it has safely shut down to prevent overheating.

Your boiler's electronic control panel is not receiving power or cannot communicate properly, meaning the screen is blank or showing scrambled information.

Your boiler has detected that the exhaust gases are becoming dangerously hot and has shut down to prevent damage or overheating.

Your boiler has detected that the water pressure in your heating system is too high and has shut itself down to prevent damage.