D4 213 — Flow/return temperature sensor rising too quickly

What does D4 213 mean?

The actual temperature recorded by the flow or return temperature sensor is rising too quickly. This indicates a potential overheating issue or sensor malfunction.

• Restricted water flow in the system.
• Faulty temperature sensor.
• Pump malfunction.
• Control board error.

Click steps to track your progress.

1. 1

   Check the boiler's pressure gauge and ensure it is within the recommended range; top up if low.

2. 2

   Ensure all radiator valves are open, especially on the return side, to allow proper water circulation.

3. 3

   Reset the boiler. If the rapid temperature rise continues, contact a qualified heating engineer.