BoilerFaultCodesYour boiler’s temperature sensors are giving conflicting readings, causing the system to shut down to prevent overheating.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Flow and/or return NTC fault | Flow and/or return NTC is defective (tolerances too big)
What causes this fault?
This fault occurs when the boiler's internal computer notices that the flow and return temperature sensors are reporting values that are too far apart or inconsistent with each other. The most common reason is that one of these sensors has drifted out of calibration or failed entirely, meaning the boiler can no longer safely monitor how hot the water is. To prevent the system from overheating, the boiler shuts down as a safety precaution.
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.72 — 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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