BoilerFaultCodesYour boiler has lost its ability to accurately measure temperature, causing it to shut down to prevent overheating.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Control thermistor fault
What causes this fault?
This fault occurs when the internal sensor responsible for monitoring the temperature of the water leaving the boiler fails or provides an unreadable signal. It is usually caused by the sensor's internal electrical resistance failing over time or damage to the wiring connecting it to the main control board. Without accurate temperature data, the boiler cannot safely regulate its heat output and will shut down as a precaution.
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 E1 — no call-out fees, no surprises.
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Could it be time for a new boiler?
If repair costs are adding up, a new energy-efficient boiler could be the smarter long-term choice.
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