25 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Replaced by: CDi Classic
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Your boiler has temporarily stopped trying to heat up because it could not safely light the flame.
Your boiler has detected an issue with the automatic air vent, which helps remove trapped air from the system.
Your boiler is struggling to transfer heat between its internal systems, which means it cannot reliably provide hot water or heating.
Your boiler has detected an issue with the internal fan, which is responsible for safely removing harmful exhaust gases outside your home.
Your boiler is failing to ignite the flame needed to produce heat and hot water.
Your boiler's internal gas system is not running correctly, meaning the unit cannot safely ignite to provide heating or hot water.
Your boiler's main control computer has encountered a serious internal error and has safely shut down to prevent damage.
Your boiler is not detecting the correct airflow needed to operate safely, so it has shut itself down to prevent any issues.
Your boiler has detected an issue with the fuel supply or combustion process, meaning it has safely shut itself down to prevent unsafe operation.
Your boiler has detected an issue with the fuel delivery system specifically related to the propane gas supply, preventing it from igniting safely.
Your boiler has identified a problem with how the gas-to-air mixture is being delivered to the burner, which indicates an issue with your fuel supply settings.
Your boiler has temporarily stopped working because it cannot safely detect the burner flame.
Your boiler has lost water pressure, and the internal component used to refill it is likely disconnected or faulty.
Your boiler is unable to regulate the gas supply correctly, which is preventing it from firing up to provide your heating and hot water.
Your boiler has detected an issue with its internal gas supply system which is preventing it from heating your home safely.
Your boiler is not detecting the electrical power it needs to operate safely and properly.
Your boiler has detected an internal electrical problem with its main control unit, meaning it has safely shut down to prevent any further issues.
Your boiler has detected an internal electrical or display error indicated by a fault with the green indicator light.
Your boiler is failing to register or respond when you turn on the central heating.
Your boiler is not turning on when you turn on the hot water tap.
Your boiler has entered a special frost protection mode or is experiencing an internal electronic control issue.
Your boiler has experienced an internal safety lock-out due to a system fault, meaning it has temporarily stopped working to keep your home safe.
Your boiler has registered an unspecified internal safety fault that requires a professional engineer to properly diagnose and resolve.
Your boiler has temporarily shut down because the water inside it has become dangerously hot, which usually points to a blockage in circulation or a faulty pump.
Your boiler has temporarily stopped working because it is getting incorrect temperature readings from its internal components.
BoilerFaultCodes