BoilerFaultCodesYour boiler's internal thermometer for the central heating system has stopped working correctly, which means the system cannot monitor or control the water temperature.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Failed heating sensor – issue with heating sensor and could need replacing
What causes this fault?
This fault occurs when the boiler's central heating sensor either develops an electrical short or stops communicating with the main control board. The most common reason is that the internal thermistor has reached the end of its lifespan or has been damaged by constant temperature fluctuations, preventing the boiler from safely monitoring heat levels.
This fault is frequently seen in autumn when the heating system is first turned back on after being dormant all summer, putting sudden thermal stress on the aging sensor.
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 12 — no call-out fees, no surprises.
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Ravenheat CSI 120 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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