BoilerFaultCodesYour boiler has stopped working because its internal sensors or control system are struggling to talk to each other correctly.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Temporary error with communication, negative temperature coefficient thermostat (NTC) or flue sensor. Sensor could also be unconnected or have a bad connection.
What causes this fault?
This fault happens when the boiler's main control board loses touch with the sensors that monitor heat levels. It is usually caused by a faulty temperature sensor providing an impossible reading or a loose wire preventing the components from 'talking' to each other. When the brain of the boiler isn't sure how hot the water or exhaust gases are, it shuts down as a safety precaution.
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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Gas Safe Register →Protect yourself from future repair bills
A boiler cover plan would cover faults like H.03 -.00 — no call-out fees, no surprises.
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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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