E5 218 — Flow temperature too high

What does E5 218 mean?

The boiler's flow temperature is too high, or the temperature captured by the flow temperature sensor has exceeded 105°C. This is a critical safety fault.

• Restricted water flow through the heat exchanger.
• Pump malfunction or airlock.
• Faulty flow temperature sensor.
• Over-firing of the burner.

Click steps to track your progress.

1. 1

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

2. 2

   Check the boiler pressure and top up if it is low.

3. 3

   Ensure all radiator valves are fully open to allow water circulation.

4. 4

   Contact a Gas Safe registered engineer to diagnose the cause of the overheating.