BoilerFaultCodesThe 6 most common faults
Your boiler has switched itself off because the water temperature is rising too quickly, usually due to poor water flow through the system.
Why it happens: This fault occurs when water cannot move through the boiler fast enough to carry heat away, causing a rapid temperature spike. The most common reasons are a failing water pump, a blockage caused by sludge in the pipework, or air trapped within the heat exchanger.
Check that all radiator valves are fully openEnsure the central heating pump is running and hasn't seizedCheck that any external bypass valves are open
Your boiler has stopped working because it cannot correctly measure the temperature of the water returning to the unit.
Why it happens: This fault occurs when the internal electronic sensor responsible for monitoring the water coming back into the boiler becomes damaged or loses its connection. Over time, heat stress or moisture can cause the sensor to degrade, preventing it from sending a reliable signal to the main control board. Without this vital temperature data, the boiler shuts down as a safety precaution to prevent internal overheating.
Full guide for 37Your boiler is currently trying to start up but is failing to detect a flame, meaning it cannot ignite to provide heat or hot water.
Why it happens: This fault occurs when the boiler's internal sensors detect that the water returning from your radiators is hotter than the water leaving the boiler. This usually means the water is physically being pushed the wrong way through the system or a sensor has failed and is sending incorrect data to the control board. It is often triggered by a failing pump or a blockage that has forced the water to circulate in reverse.
Full guide for 2$Your boiler is failing to start because it cannot successfully ignite the burner, so it is shutting itself down as a safety precaution.
Why it happens: This fault occurs when the boiler's control system attempts to start the fan to clear out gases, but detects no rotation or movement. It is usually caused by the fan motor burning out after years of use, or a loose connection in the wiring harness that prevents the signal from reaching the motor. Without the fan spinning at the correct speed, the boiler cannot safely ignite and will shut down as a precaution.
Full guide for 2*Your boiler is currently trying to light its flame but is failing to do so after a few seconds of attempting.
Why it happens: This fault occurs when the boiler's brain and the fan stop talking to each other properly. It is usually caused by the fan motor wearing out and spinning at the wrong speed, or a failure in the electronic control board that sends instructions to the fan. Without a reliable signal from the fan, the boiler shuts down as a safety precaution to ensure exhaust gases are properly cleared.
Full guide for 2(Your boiler’s internal computer has developed a serious electronic fault and can no longer control the heating safely.
Why it happens: This fault occurs when the boiler's internal processor or memory chips suffer an electronic component failure, meaning the motherboard can no longer process data or safety instructions. The most common reason is natural electrical wear and tear over time, though it can also be triggered by a sudden power surge or moisture getting into the casing.
Full guide for 10on the Remeha Quinta 30
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 Remeha 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