Your boiler's computer brain has encountered a communication error or internal failure related to how it monitors system pressure.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Boiler Control Assembly (Use with ‘Huba’pressure transmitter only)
What causes this fault?
This fault occurs when the boiler's main control board loses communication with the digital pressure sensor or detects an internal electronic failure. It is often caused by a malfunctioning circuit board that can no longer process signals correctly, or a sensor that has failed and is sending unreadable data. Essentially, the boiler shuts down because it can no longer safely verify if there is enough water pressure to operate.
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 H00266 — no call-out fees, no surprises.
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