How much does it cost to fix Worcester Bosch error code 90?

Typical repair cost for the Worcester Bosch 90 fault is £150-300 including labour.

90 High

Worcester Bosch 90 Fault Code

Q: What does the Worcester Bosch 90 fault code mean?

Your boiler has detected that it is not operating according to its expected energy settings, which typically indicates an issue with the internal electronics or the gas-to-air ratio setup.

The Worcester Bosch 90 fault code means: your boiler has detected that it is not operating according to its expected energy settings, which typically indicates an issue with the internal electronics or the gas-to-air ratio setup.. It appears on 1 Worcester Bosch model in our database.

Technical description: Heat output 27.2 kW / Heat input 27.5 kW (RD532i L.P.G) or Heat output 33.4 kW / Heat input 33.8 kW (RD537i L.P.G)

Typical repair cost £150-300 (including labour)

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Worcester Bosch models that show the 90 fault code

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

537i Repair: £150-300

Source

Worcester Bosch 90 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