20 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Replaced by: iC System
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Your boiler has stopped because an external safety device, such as a fire alarm or frost thermostat, has told the system to shut down for safety reasons.
Your boiler has paused the heating because the water is not circulating fast enough between the appliance and your radiators, causing a heat buildup inside the unit.
Your boiler has detected that the water is not flowing through the system as efficiently as it should while heating your hot water, causing it to temporarily pause that function to protect itself.
Your boiler’s internal computer has lost the correct settings for how much power it should use, causing it to stop working to protect itself.
Your boiler has detected that water is circulating unexpectedly while it is trying to stay idle, so it has paused itself to prevent damage until the temperature settles.
Your boiler has automatically paused its operation because the exhaust fumes inside the unit have become too hot, and it will try to start again once it has cooled down sufficiently.
Your boiler has detected that a key safety sensor measuring exhaust gases has become unplugged, so it has safely shut itself down to prevent operation.
Your boiler has detected a faulty sensor reading in the exhaust system and has safely shut down to prevent incorrect operation.
Your boiler is currently unable to sense water moving through it, so it is running an automatic internal process to clear out any trapped air bubbles before it will allow the heating to start again.
Your boiler is failing to light the internal flame needed to produce heat and hot water.
Your boiler has detected an electrical fault in its internal control system that is preventing it from operating safely.
Your boiler is failing to light the internal burner, meaning it cannot produce any heat or hot water.
Your boiler has detected an issue with its power supply or an internal electrical signal fluctuation, which has caused it to stop working for safety reasons.
Your boiler is having difficulty correctly adjusting its internal gas and air settings to run efficiently.
Your boiler has stopped working because a protective electrical fuse inside the main control board has blown, preventing the system from powering up safely.
Your boiler has detected that the water inside the system has become dangerously hot and has shut itself down to prevent damage.
Your boiler has detected that the water returning from your radiators is getting too hot, so it has shut itself down to prevent any damage.
Your boiler is unable to confirm that the internal fan is spinning correctly, so it has safely shut down to prevent overheating.
Your boiler's electronic control panel is not receiving power or cannot communicate properly, meaning the screen is blank or showing scrambled information.
Your boiler has detected that the exhaust gases are becoming dangerously hot and has shut down to prevent damage or overheating.
Not faults — these are normal operating states. Tap to expand.
BoilerFaultCodes