E20 — Central Heating sensor Fault

What does E20 mean?

This code indicates a fault with the Central Heating NTC (Negative Temperature Coefficient) sensor, which measures the heating water temperature. The boiler display will show 'E' alternating with '20'. This usually means the sensor itself or its wiring is defective.

• Faulty Central Heating NTC sensor.
• Damaged wiring to the NTC sensor.
• Loose connection at the NTC sensor.

Click steps to track your progress.

1. 1

   Note the error code E20 from the boiler display.

2. 2

   Ensure the electrical supply to the boiler is stable (230V ~ 50Hz).

3. 3

   Check that all external controls are calling for heat.

4. 4

   Contact a qualified heating engineer, informing them of the E20 error code.