BoilerFaultCodesThe 3 most common faults
Your boiler has stopped working because water is not moving through the system properly, which is causing it to overheat and shut down for safety.
Why it happens: This fault occurs when the water inside the boiler gets too hot because it isn't being moved away quickly enough to the radiators. The most common reason is a failing internal pump that has stopped spinning, or a blockage of debris and sludge that is restricting the flow of water. It can also be caused by air trapped inside the unit which prevents the pump from working effectively.
Check that your system pressure is between 1.0 and 1.5 bar on the pressure gaugeEnsure all radiator valves and isolation valves under the boiler are fully openBleed your radiators to remove any trapped air that might be blocking circulationPress the reset button to see if the boiler restarts
Your boiler has detected a fault with the sensor that monitors exhaust gases, and as a safety precaution, it will not operate until this is fixed.
Why it happens: This fault occurs when the internal sensor responsible for monitoring the temperature of the exhaust gases becomes faulty or disconnected. The most common reason is natural wear and tear or heat damage to the sensor's thermistor, which prevents it from sending an accurate reading to the main control board. As a safety measure, the boiler shuts down to prevent any risk of the flue system overheating.
Full guide for E23Your boiler has detected a problem with the sensor that monitors the water temperature returning from your radiators, preventing the system from operating correctly.
Why it happens: This fault occurs when the boiler's control system receives an incorrect or missing signal from the sensor that monitors water returning from your radiators. The most common reason is that the internal components of the sensor have degraded over time or the electrical connection between the sensor and the main control board has become loose or damaged.
Full guide for E24on the Ravenheat CSI 85
Based on parts cited in our fault code database. Your engineer will confirm what's actually needed after diagnosis.
Call a Gas Safe engineer if…
- You can smell gas or see signs of a leak
- The Ravenheat shows an Emergency or High severity code
- The boiler keeps locking out after repeated resets
- You've tried the DIY checks and the fault hasn't cleared
- There's visible water leaking from the boiler
- The flame is yellow or orange instead of blue