BoilerFaultCodesYour boiler has lost the ability to monitor the water temperature in your hot water cylinder due to an electrical connection fault.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Short circuit: Cylinder temperature sensor. NTC sensor defective, short circuit in the cable harness, cable/housing
What causes this fault?
This fault occurs when the electrical signal from the hot water cylinder’s temperature probe is interrupted or corrupted. The most common reason is that the internal wiring of the sensor has failed or become damaged, causing a short circuit that prevents the boiler from knowing how hot your water is. In some cases, moisture ingress or loose connections at the sensor housing are the physical culprits.
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 F.91 — 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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