BoilerFaultCodesYour boiler's internal thermometer that monitors water temperature has stopped working correctly, causing the system to shut down 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: CH flow NTC sensor defective or incorrectly fitted
What causes this fault?
This fault occurs when the sensor responsible for measuring the temperature of the water leaving the boiler fails to send a reliable signal to the main control board. The most common reason is that the internal components of the sensor have degraded over time, or the electrical connection has become loose or corroded. Because the boiler no longer knows how hot the water is, it shuts down to prevent the unit from overheating.
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 E2 — no call-out fees, no surprises.
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