Your boiler is struggling to correctly measure the temperature of your hot water, which usually means your taps will only provide lukewarm or cold water.
This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.
Technical description: Fault on Hot Water Sensor
What causes this fault?
This fault occurs when the boiler's internal computer stops receiving a reliable signal from the sensor that monitors your tap water temperature. The most common reason is that the sensor has physically degraded or developed an electrical short, preventing it from telling the boiler to turn the burner on for hot water.
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 27 — no call-out fees, no surprises.
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