BoilerFaultCodesYour boiler's electronic brains are essentially having a communication breakdown and don't recognize each other, causing the unit to stop working 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: Invalid device specific communication (ASIC and main board)
What causes this fault?
This fault occurs when the main control board and the display interface within the boiler fail to identify one another. The most common reason is a memory error or electronic failure after a power surge, though it can also be caused by loose wiring connections between the two boards.
This fault is often triggered during the winter months when power fluctuations or surges are more frequent during stormy weather.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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A boiler cover plan would cover faults like F.70 — no call-out fees, no surprises.
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