BoilerFaultCodesYour boiler has lost its ability to measure the temperature of the water used for your radiators, causing the system to stop working for safety.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Central heating thermistor sensor fault
What causes this fault?
This fault occurs when the sensor responsible for monitoring the heat of the water leaving your boiler has failed or is sending an incorrect signal. The most common reason is that the internal component has simply worn out over time, though it can also be caused by loose or damaged electrical connections between the sensor and the main control board.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
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A boiler cover plan would cover faults like E20 — 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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