BoilerFaultCodesYour boiler is unable to heat your hot water because one of the internal temperature sensors has developed an electrical fault.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: No DHW heating - Cylinder temperature sensor/comfort sensor/loading sensor shorted out
What causes this fault?
This fault occurs when the internal electrical sensors responsible for monitoring your hot water temperature stop sending a valid signal to the boiler’s control board. The most common reason is that the sensor's internal wiring has short-circuited or the electrical connections have corroded over time, preventing the boiler from knowing how hot your water is. Because the system can no longer safely regulate the temperature, it disables the hot water function as a protective measure.
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 50 — no call-out fees, no surprises.
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Viessmann Vitodens 333 is discontinued — time for a new one?
Parts for discontinued models can be hard to find and expensive. A new A-rated boiler could save you money on both repairs and energy bills.
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