High Lockout
Ad on Worcester Bosch WR325 RSF

Your boiler is having trouble communicating with the sensor that monitors the temperature of your hot water cylinder.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Call an engineer soon

Book a Gas Safe engineer within 24 to 48 hours. Your boiler may be unsafe or could break down completely if left.

Technical description

Cylinder temperature sensor (NTC) not recognized

What causes this fault?

This fault occurs when the boiler's main control board loses the electrical connection to the sensor responsible for monitoring your hot water tank’s temperature. The most common reason is that the sensor itself has developed an internal fault or the wiring connecting it to the boiler has become loose or damaged over time.

Engineer required

This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Related fault codes

A7View →E9View →

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