284 High

Worcester Bosch 284 Fault Code

The Worcester Bosch 284 fault code means: your boiler is struggling to deliver the correct mix of air and gas required to light the burner safely.. It appears on 21 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?

This fault occurs when the boiler's internal computer is unable to communicate with or control the valve that regulates the flow of gas into the burner. It signifies a hardware failure where the gas valve remains closed or unresponsive, preventing the boiler from creating a flame to provide heating or hot water. The most common reasons include a faulty electronic control board, a loose wiring connection, or a mechanical failure within the gas valve itself.

Typical repair cost £180-350 (including labour)

Engineer required

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

Find a Gas Safe engineer

Search the official register for a qualified engineer in your area.

Gas Safe Register →

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 27 April 2026