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Knowledge document #3391
FRITZ!DECT 301
This support document is available for the following products:

Using the FRITZ!DECT radiator control's open window detection

To save energy, the open window detection of the radiator control, for example FRITZ!DECT 301, closes the radiator valve while the room is being aired out. Open window detection is always active for each individual radiator control, even if you are using a FRITZ!DECT smart plug as an external temperature sensor, for example.

There are various settings options for open window detection. You can also manually trigger open window detection on the radiator control.

Note:All instructions on configuration and settings given in this guide refer to the latest FRITZ!OS for the FRITZ!Box.

1 How open window detection works

The open window detection of the radiator control closes the radiator valve when the radiator control measures a temperature drop of 1.1 degrees within 2 minutes. You can increase the sensitivity to 0.7 degrees or reduce it to 1.9 degrees in the FRITZ!Box. In the factory settings, the valve is set to remain closed for 10 minutes. You can set the duration in the FRITZ!Box user interface.
As soon as the valve is closed, "Fenster-auf" and the time when open window detection will stop again is then shown on the display of the radiator control.

Due to structural and thermal conditions, the radiator control may not accurately register a decrease in temperature. In this case, you can set different values for the sensitivity of open window detection in the FRITZ!Box. If changing these values does not automatically trigger the function, you can simply manually trigger the open window detection on the radiator control.

If you organized your radiator controls FRITZ!DECT 301 into groups and FRITZ!OS 7.20 or later is installed on your FRITZ!Box, open window detection is triggered on all of the radiator controls in this group as soon as the function is triggered automatically or manually on one of the radiator controls in the group.

2 Setting sensitivity and ventilation duration

  1. Click "Home Network" or "Smart Home" in the FRITZ!Box user interface.
  2. Click "Smart Home" in the "Home Network" menu or click "Device Management" in the "Smart Home" menu.
  3. Click the (Edit) button for the radiator control you want to set up the function for.
  4. Under "Open window detection", set the "Sensitivity" with which the radiator control should react to temperature drops and trigger open window detection:
    1. Click "high" to trigger open window detection when the temperature drops 0.7 degrees.
    2. Click "medium" to trigger open window detection when the temperature drops 1.1 degrees.
    3. Click "low" to trigger open window detection when the temperature drops 1.9 degrees.
  5. In the "Valve closed for" field, enter how long in minutes the valve should remain closed. You can enter a value between 1-120 minutes. For example, if you usually air your bathroom for 20 minutes, enter "20". When this time has elapsed, the radiator control will behave as usual.
  6. Click "OK" to save the settings.

3 Manually triggering open window detection on the radiator control

If the automatic open window detection cannot be triggered automatically due to the existing conditions, the only option is to trigger the open window detection manually:

  1. Push the (open window detection) button on the radiator control for 2 seconds. Now the valve shuts for the amount of time you configured in the FRITZ!Box.
  2. You can always change the amount of time by pushing the plus or minus button on the radiator control. The amount of time is then shown on the display of the radiator control.
  3. If you want to heat again before this time has elapsed, push the (open window detection) button on the radiator control for 2 seconds to return to the regular schedule or use the boost function.