Medium Lockout
E50 on Potterton Assure Combi / System

Your boiler's temperature sensor for hot water has developed a fault or a loose connection, meaning the system cannot accurately measure how hot the water is.

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

Domestic hot water (DHW) negative temperature coefficient (NTC) sensor (tank boiler) (s.c) or DHW NTC sensor (tank boiler) (o.c.) Fault

What causes this fault?

This fault occurs when the sensor responsible for measuring your hot water temperature becomes faulty, either by burning out internally or suffering from a loose electrical connection. Without an accurate reading from this sensor, the boiler's computer cannot safely determine how hard to fire the burner, causing it to stop heating your water.

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 →E28View →E110View →

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