BoilerFaultCodesYour boiler has detected an internal sensor failure and has stopped providing hot water or heating to protect the system.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Temperature sensors faulty (DHW or CH NTC)
What causes this fault?
This fault occurs when the boiler's control board can no longer accurately read the temperature because the internal sensors have failed or become disconnected. Over time, these small probes can degrade due to constant heat cycles or moisture, leading them to provide incorrect signals that force the system to shut down for safety.
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 20 — no call-out fees, no surprises.
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