BoilerFaultCodesThe 6 most common faults
Your boiler has stopped working because it cannot detect water moving through the system to keep it running safely.
Why it happens: This fault occurs when the boiler's internal sensors do not detect any water movement after the pump has started. The most common cause is a seized or failing circulation pump that is no longer able to push water through the heat exchanger, but it can also be triggered by severe air locks or a total blockage in the heating circuit.
Check that your external heating valves or isolation valves are fully open.Ensure your radiator valves (TRVs) are turned up and not all closed.Check the boiler pressure gauge and top it up to 1.5 bar if it is too low.Gently bleed your radiators to remove any trapped air pockets.
Your boiler has become too hot and has shut itself down as a safety precaution to prevent damage.
Why it happens: This fault occurs when the water inside the boiler reaches an unsafe temperature, triggering a safety sensor to cut the power. The most common reasons are a pump failure preventing water from moving through the system or a blockage caused by a build-up of debris and sludge.
Check that all radiator valves are fully open to allow water to circulate.Ensure there is enough pressure in the system by checking the pressure gauge (aim for 1.5 bar).Press the 'Reset' button on the front of the boiler panel once the unit has cooled down.
Your boiler is failing to light the gas to create heat, so the system has shut itself down for safety.
Why it happens: This fault occurs when the boiler tries to light the gas but fails to detect a flame after several attempts. The most common reasons are a lack of gas supply to the unit, a worn-out spark plug that can no longer create a flame, or a faulty internal component that controls the gas flow.
Check if other gas appliances, like a cooker, are working to confirm gas supply.If it is freezing outside, check if the white plastic condensate pipe leading outdoors is frozen.Press the 'Reset' button on the boiler control panel once.
Your boiler has detected that there is not enough water pressure or water is not moving through the system properly to operate safely.
Why it happens: This fault occurs when the boiler's internal sensors detect that water isn't moving through the unit, which risks the heat exchanger overheating. The most common reasons are a seized internal pump, a build-up of sludge blocking the pipes, or a faulty pressure sensor that is incorrectly reporting a lack of water.
Check the pressure gauge on the front of the boiler; it should be between 1 and 1.5 bar.If the pressure is low, use the filling loop handles underneath the boiler to top it up until the needle reaches the green zone.Ensure all radiator valves and isolation valves under the boiler are fully open.Reset the boiler by turning the control knob to 'RE' or pressing the reset button.
Your boiler is failing to keep its flame lit, which means it cannot heat your home or water.
Why it happens: This fault occurs when the boiler successfully lights a flame but then loses the signal needed to keep it running. The most common reason is that the internal sensors are dirty or worn out and can no longer 'see' the flame, or the gas valve is failing to maintain a steady flow of fuel.
Check if other gas appliances in your home, like a hob, are working correctlyEnsure your gas meter has credit if you use a pre-payment meterRestart the boiler by pressing the 'Reset' button
Your boiler is not providing central heating even though it may still be providing hot water.
Why it happens: This fault occurs when the boiler is receiving a signal to provide hot water but is failing to recognize or act on the command to heat your radiators. The most common reason is a failure in the communication between your external room thermostat and the boiler, or a mechanical failure of the internal valve that directs heat to the central heating circuit.
Check that your room thermostat or programmer is set higher than the current room temperatureEnsure the heating mode is active on the boiler displayCheck that the radiator valves are open and not turned to zero
on the Ideal Logic Max Heat
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
Avoid the next call-out bill
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