Understanding Worcester Bosch Gas and LPG Boiler Error Codes

Your Worcester Bosch boiler is a reliable heating system, but like any complex appliance, it can develop faults. When your boiler displays an error code, it’s the system’s way of alerting you to a problem. Understanding what these codes mean can help you decide whether it’s a simple fix you can handle or a job for a Gas Safe registered engineer.

What Are Worcester Bosch Boiler Error Codes?

Worcester Bosch boilers use error codes to indicate specific issues within the system. These codes are usually displayed on the boiler’s digital screen, or in older models, via flashing lights. The codes are different for gas and LPG boilers in some cases, though many are shared across both fuel types.

Common Gas Boiler Error Codes

Gas boilers can display a wide range of error codes. Some of the most frequent include:

• EA – No flame detected: The boiler tried to ignite but failed. Causes can include a blocked gas supply, faulty ignition electrodes, or air in the gas line.
• A7 – Hot water temperature sensor fault: Indicates a problem with the temperature sensor, affecting hot water performance.
• CE – Air pressure switch issue: Often caused by a blocked flue or fan problem.
• E9 – Overheating detected: The system has detected a flow temperature that is too high, possibly due to a blocked pump or radiator valve.
• D1 – Pump or wiring fault: This code appears if the pump isn’t operating correctly or there’s an electrical issue.

LPG Boiler Error Codes

LPG boilers share many of the same codes as gas boilers, but fuel differences can make some issues more common:

• EA – No flame detected: LPG boilers are more sensitive to low gas pressure or incorrect regulator settings.
• F7 – Flame detected unexpectedly: Often related to incorrect combustion settings for LPG.
• CE – Air pressure switch fault: Can occur if the flue or fan isn’t correctly configured for LPG.
• E9 / E5 – Overheating or high temperature: Common if there’s restricted flow or incorrect combustion adjustments.
• A7 – Hot water sensor fault: Same as with gas boilers, but check LPG-specific flow settings.

What to Do When You See a Boiler Error Code

Before calling an engineer, you can perform a few simple checks:

• Ensure the boiler has power and the timer or thermostat is set correctly.
• Check gas or LPG supply and confirm the tank isn’t empty (for LPG).
• Inspect for obvious blockages or obstructions near the flue or air intake.
• Try a single boiler reset using the manufacturer’s instructions. Avoid repeated resets.

If the error persists, it’s important to contact a Gas Safe registered engineer for gas boilers or a certified LPG engineer for LPG systems such as Matt Grange. Attempting repairs without proper training can be dangerous.

Preventing Boiler Errors

Regular maintenance is the best way to prevent error codes. Consider:

• Annual servicing by a Gas Safe or OFTEC registered engineer
• Bleeding radiators and checking pressure levels regularly
• Keeping flues, vents, and airways clear
• Replacing worn components such as pumps, sensors, or ignition electrodes promptly

Need Help With Your Worcester Bosch Boiler?

Whether your boiler is running on gas or LPG, understanding error codes can help you identify issues faster. For any persistent faults, our Gas Safe registered engineers are ready to diagnose and repair your system safely and efficiently. Contact us today to schedule a service and keep your home warm and worry-free.