Medium Lockout
27 on Potterton Performa 28i

Your boiler is struggling to correctly measure the temperature of your hot water, which may lead to lukewarm water or no hot water at all.

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 boiler's internal computer can no longer read a reliable signal from the sensor responsible for monitoring your tap water temperature. The most common reason is that the sensor has either suffered water damage from a small leak or has simply worn out over years of constant heating and cooling.

Engineer required

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

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