BoilerFaultCodesYour boiler has lost communication with the temperature sensor on your hot water cylinder, meaning it cannot tell how hot your water is.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Tank NTC fault
What causes this fault?
This fault occurs when the boiler can no longer receive an electrical signal from the temperature probe attached to your hot water tank. The most common cause is a failure of the sensor's internal components or a loose connection in the wiring that links the cylinder to the boiler's 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 F13 — no call-out fees, no surprises.
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