BoilerFaultCodesYour boiler has detected an internal communication or airflow issue that has caused it to shut down for safety.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Code plug missing or failed. CH or DHW Sensor fault or out of position. Air pressure switch fault or condense in tubes. Fan fail or stiff. Blocked flue. Faulty harness. Board fault.
What causes this fault?
This fault occurs when the boiler's internal computer loses communication with its key safety components or senses that air isn't moving through the system correctly. It often signifies that the fan cannot spin properly or the sensors responsible for monitoring heat and airflow have detected an unsafe operating condition. These sensors act as a safety net, shutting the system down to prevent damage or the release of exhaust gases into the home.
This issue is more frequent during periods of heavy rain or high humidity, as moisture can build up within the air pressure tubes and disrupt the signal required for the boiler to fire.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
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A boiler cover plan would cover faults like Flash 4 times per second — no call-out fees, no surprises.
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Parts for discontinued models can be hard to find and expensive. A new A-rated boiler could save you money on both repairs and energy bills.
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