High Lockout
E.04 – .01 on Baxi 200 Combi (range)

Your boiler has stopped working because it cannot correctly measure the temperature of the water leaving the unit due to a faulty internal sensor or wiring.

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

Flow temperature sensor short-circuited. Sensor not or badly connected, bad connection or sensor fault.

What causes this fault?

This fault occurs when the boiler's control board receives an impossible electrical signal from the sensor that monitors the hot water leaving the unit. The most common reason is that the internal sensor has suffered an electrical short-circuit or the delicate wiring connecting it to the main computer has become loose or damaged.

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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