BoilerFaultCodesYour boiler has detected a faulty internal temperature sensor, which means it cannot accurately monitor the water temperature and has stopped 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: CH flow NTC sensor defective.
What causes this fault?
This fault occurs when the boiler's internal thermometer, which monitors the water temperature leaving the heat exchanger, fails to provide a correct reading. The most common reason is that the sensor's internal electrical resistance has drifted out of range due to age, or the connection pins have become corroded, preventing the boiler from operating safely.
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.
Gas Safe Register →Protect yourself from future repair bills
A boiler cover plan would cover faults like E2 — no call-out fees, no surprises.
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