Medium Warning
E321 on Potterton Assure Combi / System

Your boiler has detected an issue with the sensor that monitors the temperature of your hot water, meaning your taps may not get warm.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Book a service

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

Hot water fault

What causes this fault?

This fault occurs when the sensor responsible for measuring the temperature of your hot water fails or sends an incorrect signal. The most common reason is that the internal component has worn out over time or the electrical connection between the sensor and the main control board has become loose or damaged.

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Related fault codes

E20View →E110View →

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