High Lockout
é2 on Remeha Avanta 18V

Your boiler has detected that water is returning to the unit hotter than when it left, which usually indicates the internal sensors are confused or there is a problem with the way water is circulating.

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

Return temperature is higher than the flow temperature

What causes this fault?

This fault occurs when the boiler's internal sensors detect that the water coming back from your radiators is hotter than the water being sent out, which is physically impossible under normal conditions. The most common reason is that one of the temperature sensors has failed or is sending the wrong information to the control board. It can also happen if the pump is moving water in the wrong direction or if there is a significant blockage in the system's pipework.

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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