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blue constant light

Solid blue LED — Unit is operating

Daikin · Altherma 3 H HT W

What does blue constant light mean?

The status indicator light on your Daikin Altherma 3 H HT W is constantly lit blue. This signifies that the unit is currently active and performing its heating or cooling operation.

Common Causes

  • Unit is actively heating or cooling the space.
  • Demand for heating or cooling is being met.

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    If the unit is operating as expected, no action is needed.

  2. 2

    If the operation is not desired, check the selected operation mode ('Heating', 'Cooling', or 'Automatic').

  3. 3

    Adjust the set temperature or schedule if needed.

  4. 4

    Consult the 'Space operation modes' section to ensure the correct mode is selected for your needs.

Browse all codes in this manual (11)
Verified technical data. Last updated: April 2026

Related Faults

Blinking blue LEDBlinking blue LED — Unit is in standby modeBlinking red LEDBlinking red LED — An error has occurredContinuous blue LEDContinuous blue LED — Unit is operating
Source: Daikin Altherma 3 H HT W
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