Medium Lockout
10 on Potterton Performa 24 Eco HE

Your boiler's temperature sensor for hot water has stopped working correctly, meaning your taps might not get warm or the temperature could be inconsistent.

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

Fault on Hot Water Sensor

What causes this fault?

This fault occurs when the internal sensor responsible for monitoring your tap water temperature fails to send a reliable signal to the main control board. The most common reason is that the sensor's internal components have degraded over time due to constant heating and cooling cycles, or the electrical connection has become corroded. Because the boiler no longer knows how hot the water is, it stays off as a safety precaution to prevent scalding.

Engineer required

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

Find a Gas Safe engineer
Search the official register →

Related guides you might find useful

No hot water but heating works

Almost always a stuck diverter valve on combis.

Read →

Boiler keeps cutting out

Lockout fault with a reset-needed pattern.

Read →

Yellow or orange flame — CO safety

Safety-critical — turn off, read this.

Read →