Error 20 — Central Heating NTC sensor fault

What does 20 mean?

Error code 20 points to a problem with the Central Heating NTC (Negative Temperature Coefficient) supply sensor. This sensor is crucial for measuring the heating system's water temperature.

• Faulty CH NTC supply sensor, providing incorrect resistance readings.
• Loose or broken wires in the wiring harness connected to the sensor.
• Faulty PCB (Printed Circuit Board).

Click steps to track your progress.

1. 1

   Take an Ohm reading of the CH NTC supply sensor and compare it to the NTC sensor chart; replace the sensor if it's out of calibration.

2. 2

   Inspect the wiring harness for the CH NTC sensor, looking for any loose or broken wires.

3. 3

   If both the sensor and its wiring are confirmed to be good, the PCB might need to be replaced by a qualified technician.