BoilerFaultCodesYour boiler has switched itself off for safety because it detected it was getting too hot.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Red lockout light. Indicates the boiler safety cutoff may have operated, typically due to overheating.
What causes this fault?
This fault occurs when the water inside the boiler reaches an unsafe temperature, triggering a safety switch to kill the power. The most common reasons are a pump failure preventing water from moving or a blockage in the heat exchanger that traps heat inside the unit.
This issue often surfaces when the heating is first turned on in autumn, as pumps can seize up after being inactive over the summer months.
DIY fix possible
Switch the boiler off at the wall socket or fused spurWait approximately 15 minutes for the system to cool downCheck that your radiator valves are open and your water pressure is between 1 and 1.5 barTurn the power back on and press the reset button
Find a Gas Safe engineer
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A boiler cover plan would cover faults like F — no call-out fees, no surprises.
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Glow-worm Compact 75E 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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