BoilerFaultCodesYour boiler has lost its ability to accurately measure the temperature of the water used to heat your radiators, meaning your heating will likely stop working.
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 negative temperature coefficient (NTC) fault
What causes this fault?
This fault occurs when the internal sensor responsible for monitoring your heating temperatures becomes damaged or fails to send a clear signal back to the main control board. The most common reason is that the sensor has physically degraded over time or developed an electrical short, preventing the boiler from knowing how hot the water is. As a safety precaution, the boiler will stop firing to prevent overheating.
This fault is often noticed during the first cold spell of autumn when the heating system is turned on after being dormant all summer.
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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