284 High

Worcester Bosch 284 Fault Code

The Worcester Bosch 284 fault code means: your boiler is having trouble managing the balance of air and gas required for safe combustion and has locked itself out to prevent potential issues.. It appears on 11 Worcester Bosch 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: Opening air/gas ratio control valve/oil solenoid valves

What causes the Worcester Bosch 284 fault?

Valve operation sequence

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 284 fault code

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

Source

Worcester Bosch 284 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 31 August 2026