BoilerFaultCodesYour boiler's internal computer has overheated, likely due to an electrical fault or a failing circuit board.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: PCB processor temperature too high | Check earth connection or electronics defect
What causes this fault?
This fault occurs when the boiler's central control board becomes dangerously hot, often due to an internal electrical short or a failing component on the circuit board itself. The boiler shuts down immediately to protect the sensitive electronics from melting or causing further damage. The most common reason is that the motherboard has simply reached the end of its lifespan and can no longer regulate its own temperature.
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.65 — no call-out fees, no surprises.
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Vaillant Thermocompact is discontinued — time for a new one?
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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