BoilerFaultCodesYour boiler has become too hot and has shut down as a safety precaution to prevent damage.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Over temperature on primary water circuit
What causes this fault?
This fault occurs when the water inside the boiler exceeds a safe temperature limit, causing the system to shut down to protect its internal components. The most common reasons are a failed pump that isn't moving water away from the heat exchanger quickly enough, or a blockage in the pipework restricting flow.
This issue is frequently seen during the first cold spell of autumn when pumps that have been idle all summer seize up upon being restarted.
DIY fix possible
Check that your radiator valves are open to allow water to flow.Ensure there is enough pressure in the system by checking the gauge (it should be around 1.5 bar).Gently bleed your radiators to remove any trapped air that might be blocking circulation.
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A boiler cover plan would cover faults like 14 — no call-out fees, no surprises.
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Glow-worm 18si 24ci 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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