Safety first: Turn off power before working on sensor wiring.

The outdoor sensor is used for weather-compensated control in some Nibe systems.

Step 1 – Inspect outdoor sensor:
- Locate the sensor on an external wall (north or shaded side recommended).
- Check that the housing is intact and not filled with water or insects.
Step 2 – Check cable:
- Inspect the cable run for damage from UV, animals, or mechanical impact.
- Ensure the cable is firmly connected at the control board terminals.
Step 3 – Sensor test:
- With power off, disconnect the sensor and measure resistance.
- Compare to Nibe’s NTC table for the current outdoor temperature.
Step 4 – Reset and verify:
- Restore power and clear the alarm.
- Confirm that the displayed outdoor temperature is realistic.

If the sensor is faulty, replace it with a genuine Nibe outdoor sensor to ensure correct curve control.

Display shows A07; water heater may shut down and indicate outdoor sensor fault (for systems using outdoor compensation).

Possible Causes