E.01 – .12 High

Baxi E.01 – .12 Fault Code

Also written as E0112 — same fault.

The Baxi E.01 – .12 fault code means: your boiler has stopped working because it believes the water returning to the unit is hotter than the water leaving it, which usually indicates a circulation problem or a sensor error.. It appears on 24 Baxi models in our database.

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: Requires reset – temperature measured by return sensor greater than flow temperature.

What causes the Baxi E.01 – .12 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 contradicts the laws of physics in a standard heating cycle. The most common reason is a lack of water flow caused by a failing pump or a blockage, but it can also be triggered if one of the temperature sensors has become faulty and is sending incorrect data to the control board.

This issue often surfaces during the first cold spell of autumn when the heating system is turned on after being dormant all summer, which can cause the internal pump to seize.

Typical repair cost £90-180 (including labour)

DIY fix possible

Check that all radiator valves are fully openEnsure the boiler pressure is between 1.0 and 1.5 bar on the gaugePress and hold the 'R' or Reset button for five seconds

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Baxi models that show the E.01 – .12 fault code

Click a model for the full fault code list and model-specific repair notes.

Source

Baxi E.01 – .12 fault code information on this page is sourced and cross-checked against the official Baxi service / installation manuals for each affected model.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026