E9 210 — Flue gas sensor temperature too high and open

What does E9 210 mean?

The temperature measured by the flue gas sensor is too high, and the sensor circuit is open. This is a critical safety fault indicating excessive flue gas temperatures.

• Blocked or restricted flue.
• Faulty flue gas temperature sensor.
• Overheating of the combustion chamber.
• Incorrect burner settings.

Click steps to track your progress.

1. 1

   Turn off the boiler immediately and allow it to cool down.

2. 2

   Check the flue terminal outside your property for any obstructions.

3. 3

   Reset the boiler. If the error reoccurs, contact a Gas Safe registered engineer for immediate inspection of the flue and combustion system.