BoilerFaultCodesYour boiler’s internal electronics have become too hot and have shut down to prevent damage to the control board.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Electronic system temperature too high
What causes this fault?
This fault occurs when the boiler's internal control center exceeds its safe operating temperature and shuts down to prevent the circuit board from melting or catching fire. It is usually caused by an electrical component failing on the board itself or excessive heat building up inside the boiler casing due to poor ventilation. In some cases, external heat source interference or a maturing electronic component can cause this overheating.
This fault is more common during the summer months or during heatwaves, as high ambient temperatures make it harder for the internal electronics to shed heat.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
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A boiler cover plan would cover faults like F.65 — no call-out fees, no surprises.
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