How much does it cost to fix Baxi error code E.04 – .06?

Typical repair cost for the Baxi E.04 – .06 fault is £120-£350 including labour.

E.04 – .06 High

Baxi E.04 – .06 Fault Code

Q: What does the Baxi E.04 – .06 fault code mean?

Your boiler has shut down because it is getting too hot inside, likely due to a lack of water flow or a faulty sensor safety check.

Also written as E0406 — same fault.

The Baxi E.04 – .06 fault code means: your boiler has shut down because it is getting too hot inside, likely due to a lack of water flow or a faulty sensor safety check.. It appears on 24 Baxi models in our database.

Technical description: Permanent fault. Critical flue gas temperature value reached, no circulation or sensor fault.

What causes the Baxi E.04 – .06 fault?

This fault occurs when the boiler's internal components reach a dangerously high temperature, triggering a safety shutdown to prevent damage. The most common reason is that water isn't moving through the system quickly enough to carry heat away, often due to a pump failure or a blockage. It can also be caused by a faulty sensor sending an incorrect temperature reading to the boiler's computer.

This fault is more common in autumn when heating systems are first turned back on after summer, as circulation pumps can seize up during long periods of inactivity.

Typical repair cost £120-£350 (including labour)

DIY fix possible

Check if your central heating valves are openEnsure your radiator valves (TRVs) are turned upCheck the boiler pressure gauge and top up to 1.5 bar if lowReset the boiler by turning the selector switch to 'R' for five seconds

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Baxi models that show the E.04 – .06 fault code

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

Source

Baxi E.04 – .06 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