BoilerFaultCodesYour boiler is struggling to accurately measure the temperature of your hot water, which usually means your taps aren't getting hot enough or stay cold.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Cylinder charging or hot water temperature sensor faulty
What causes this fault?
This fault occurs when the boiler's internal computer stops receiving a reliable signal from the sensors that monitor your hot water temperature. The most common reason is that the sensor has either worn out internally or a connection in the wiring has become loose or corroded, preventing the boiler from knowing when to fire up to heat your water.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
Find a Gas Safe engineer
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A boiler cover plan would cover faults like 1021 — 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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