BoilerFaultCodesYour boiler is struggling to accurately check the quality of its exhaust gases, which is preventing it from completing its ignition cycle safely.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Flue gas measurement not possible. Flue gas analysis is not currently possible.
What causes this fault?
This fault occurs when the boiler's internal sensors fail to accurately measure the combustion gases during the startup phase. It is often caused by a faulty gas valve or worn electrodes failing to produce a stable flame that the system can verify. Without a reliable reading of these exhaust gases, the boiler enters a safety mode to prevent inefficient or dangerous operation.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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Could it be time for a new boiler?
If repair costs are adding up, a new energy-efficient boiler could be the smarter long-term choice.
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