How much does it cost to fix Worcester Bosch error code 40?

Typical repair cost for the Worcester Bosch 40 fault is £100-£200 including labour.

40 Low

Worcester Bosch 40 Fault Code

Q: What does the Worcester Bosch 40 fault code mean?

Your boiler is displaying a status code indicating its current operational output level rather than a fault, meaning the system is likely functioning normally.

The Worcester Bosch 40 fault code means: your boiler is displaying a status code indicating its current operational output level rather than a fault, meaning the system is likely functioning normally.. It appears on 1 Worcester Bosch model in our database.

Technical description: Heat output 12.1 kW / Heat input 12.2 kW (RD532i L.P.G) or Heat output 14.9 kW / Heat input 15.0 kW (RD537i L.P.G)

Typical repair cost £100-£200 (including labour)

DIY fix possible

Check if the display is flashing or solid; if solid, the boiler is operating normally.Observe if the boiler proceeds to heat the system after a few moments.If the code persists and the boiler fails to fire, try pressing the Reset button once.

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Worcester Bosch models that show the 40 fault code

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

537i Repair: £100-£200

Source

Worcester Bosch 40 fault code information on this page is sourced and cross-checked against the official Worcester Bosch service / installation manuals for each affected model.

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