How much does it cost to fix Baxi error code 25?

Typical repair cost for the Baxi 25 fault is £120-250 including labour.

25 High

Baxi 25 Fault Code

Q: What does the Baxi 25 fault code mean?

Your boiler is struggling to circulate water properly, likely because the pressure inside your heating system has dropped too low or the internal pump is stuck.

The Baxi 25 fault code means: your boiler is struggling to circulate water properly, likely because the pressure inside your heating system has dropped too low or the internal pump is stuck.. It appears on 7 Baxi models in our database.

Technical description: Safety Thermostat Activated (Boiler or Flue)

Typical repair cost £120-250 (including labour)

DIY fix possible

Check the pressure gauge on the front of the boiler; if it is below 1 bar, locate the filling loop (usually a silver lever or flexible hose underneath).Slowly open the filling loop to let water into the system until the gauge reads between 1 and 1.5 bar.Close the filling loop firmly once the needle is in the green zone and restart the boiler.

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Baxi models that show the 25 fault code

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

Source

Baxi 25 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