BoilerFaultCodesYour boiler has stopped heating your hot water because it can no longer detect the temperature of your hot water cylinder.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Burner blocked. Lead break - cylinder temperature sensor (system boiler).
What causes this fault?
This fault occurs when the communication link between your boiler and the hot water tank is broken, meaning the boiler no longer knows how hot your water is. The most common reason is that the internal wiring of the temperature sensor has become brittle or snapped, or the sensor itself has suffered an electrical failure. Because the boiler cannot safely monitor the temperature to prevent overheating, it stops providing hot water as a safety precaution.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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If repair costs are adding up, a new energy-efficient boiler could be the smarter long-term choice.
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