BoilerFaultCodesThe 6 most common faults
Your boiler has become too hot or water is not moving through the system properly, causing the unit to shut down for safety.
Why it happens: This fault occurs when the water inside your boiler reaches a temperature that is too high for safe operation. It is usually caused by a blockage in the pipework or a mechanical failure in the pump, which prevents water from moving away from the heat source quickly enough. In some cases, a buildup of debris or sludge in the system can restrict flow and trigger this safety shutdown.
Check that your radiator valves are fully openEnsure your boiler pressure is between 1.0 and 1.5 barBleed your radiators to remove any trapped air
Your boiler's internal memory card has developed a communication fault, meaning the control system cannot verify the specific settings for your model.
Why it happens: This fault occurs when the boiler's main control board loses its connection with the small memory chip that stores your appliance's specific tuning profile. The most common reason is that the chip card has vibrated loose, failed electronically, or the main circuit board itself can no longer read the data required to operate safely.
Full guide for C2Your boiler thinks a flame is present when it should be off, which is a safety lockout preventing the unit from starting.
Why it happens: This fault occurs when the boiler's internal sensors detect a flame after the burner should have switched off. The most common reason is a faulty sensing electrode sending a false signal, or a gas valve that is slightly sticking and allowing a tiny amount of gas to leak through when it shouldn't.
Full guide for L6Your boiler has stopped working because the amount of water inside your heating system has dropped below the required level.
Locate the filling loop, which is usually a flexible silver hose connected between two valves near your boiler.Gradually open the valves to let water into the system until the pressure gauge needle sits between 1 and 1.5 bar.Close both valves tightly and check the boiler display to see if the error code has cleared.
Your boiler's computer memory card is not reading correctly, which prevents the system from starting up safely.
Full guide for 81Your boiler has lost all power and is completely unresponsive, meaning it cannot provide any heating or hot water.
Full guide for 84on the Ideal Logic+
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
Monthly cover means no unexpected bills when your boiler breaks down.
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