BoilerFaultCodesThe 6 most common faults
Your boiler’s internal computer has encountered a critical error and needs a professional to reset or replace the main control board.
Why it happens: This fault occurs when the boiler's main control board experiences a software crash or a hardware failure within its internal circuitry. It is often caused by a voltage spike in the electrical supply or simply due to components on the board wearing out over time. Because the 'brain' of the boiler can no longer safely monitor operations, it shuts the system down as a precaution.
Full guide for 410Your boiler has detected that the temperature sensors monitoring the water going out and coming back are swapped or wired incorrectly, preventing it from heating safely.
Why it happens: This fault occurs when the boiler detects that the pipe meant to be getting hot is staying cool, while the return pipe is heating up instead. It is usually caused by the temperature sensors being clipped onto the wrong pipes during a repair or a fault in the internal wiring harness that confuses the control board.
Full guide for 424Your boiler's computer control board has developed an internal electrical fault and is unable to communicate properly with the system.
Why it happens: This fault occurs when the boiler's internal computer brain suffers a hardware failure or a breakdown in its electrical circuitry. The most common reason is age-related wear on the circuit board's components or a sudden voltage spike that has damaged the delicate electronics, preventing the boiler from sending signals to the burner or pump.
Full guide for 460Your boiler has stopped working because the water pressure inside your heating system has dropped too low.
Locate the external filling loop (a silver flexi-hose) near the boiler.Open the valves at both ends of the loop to allow water into the system.Monitor the pressure gauge on the front of the boiler until it reaches 1.5 bar, then firmly close both valves.
Your boiler has stopped working because the internal fan, which clears exhaust gases, is failing to spin as it should.
Full guide for 82Your boiler's internal electrical control unit is failing to communicate with the fan, which means the system cannot safely start the heating process.
Full guide for 83on the Ideal Response SE
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 Ideal 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