What it means
Shown as EA with 234 under it on Si, CDi and i System Compact ErP boilers, and as 234 on its own on the Greenstar 4000, 8000 Life and 8000+.
What to check, in order
- Check you have gas
Do your other gas appliances work, and does a prepayment meter have credit?
- Reset the boiler once
Press the reset button briefly.
When to call a Gas Safe engineer
If it comes back, call a Gas Safe registered engineer. Worcester's manuals list a drop in gas supply pressure, loose gas valve connections, a faulty wiring harness, water on the valve connections, or a faulty gas valve or control board.
A repair visit will usually check the gas supply, the ignition electrode and the flame sensor.
- Note the model and serial number. They're on a label on the data badge, usually under the boiler or behind the front cover.
- Write down the exact code, and what the appliance was doing when it appeared.
- Check whether it's still under warranty. If it is, the repair may cost you nothing.
Quick answers
What does the Worcester Bosch EA 234 fault code mean?
The boiler has found an electrical problem with its gas valve, such as a coil that's disconnected, so it has locked out. Shown as EA with 234 under it on Si, CDi and i System Compact ErP boilers, and as 234 on its own on the Greenstar 4000, 8000 Life and 8000+.
Can I fix Worcester Bosch EA 234 myself?
Engineer only (about 5 minutes to reset). Start with: check you have gas; reset the boiler once. If it comes back, call a Gas Safe registered engineer. Worcester's manuals list a drop in gas supply pressure, loose gas valve connections, a faulty wiring harness, water on the valve connections, or a faulty gas valve or control board.
Is Worcester Bosch EA 234 worth repairing?
Get a quote first. A loose connection is a quick fix, but a new gas valve or control board costs more, so ask for a price first.
Checked against
- Worcester Bosch Greenstar Si Compact ErP installation and servicing instructions (PDF)
- Worcester Bosch installation and servicing instructions, document 6720891161 (PDF)
Last reviewed October 2026. Manufacturers update their pages, and your manual is the final word. Spotted a mistake? Email contact@appliance-error-codes.com.