FRITZ!DECT 301 Service - Knowledge Base

FRITZ!DECT 301 Service

Room temperature deviates from the target temperature of the FRITZ!DECT radiator control

The FRITZ!DECT radiator control does not regulate the temperature according to the desired room temperature. The temperature is either above or below the desired temperature or setback temperature.

1 Checking the radiator valve

If the radiator valve cannot be moved easily, the radiator control either cannot open and close it completely, or it cannot open or close it at all. This prevents the radiator from warming up or cooling down. Therefore, check the valve pin:

  1. Remove the radiator control.
  2. Press the valve pin on the radiator several times with a solid object, for example a coin.
  3. Remount the radiator control.
  4. Once it is mounted, follow the instructions in the display of the radiator control.

2 Taking delayed display of measured temperature into account

FRITZ!DECT radiator controls measure and adjust the temperature every 2 minutes. Since they operate according to the DECT ULE (Ultra Low Energy) standard, they only communicate with the FRITZ!Box every 15 minutes to save energy and minimize DECT radiation. This may cause a delay in the display of the actual temperature measured by the temperature sensor in the user interface of the FRITZ!Box.

3 Taking slow reaction time of heating system into account

Heating systems that are temperature-controlled tend to respond slowly. To avoid overheating the room or letting it cool down too much, the radiator control does not move the valve immediately when there are slight deviations from the target temperature. Therefore, observe the heating behavior over a longer period of time by heating the room to the desired room temperature so that the heat can be distributed evenly throughout the room. The time it takes for heat to distribute nearly evenly depends upon the room height or presence of niches and bay windows, for example, and can take several hours.

4 Taking the settings of the heating system into consideration

The settings of the heating system, such as the flow temperature or a central night-time reduction, can prevent the desired room temperature from being reached. For example, the radiator is heated by a high flow temperature and radiates this heat even when the valve is already closed. A central night-time heating reduction to a lower temperature can also prevent the desired room temperature from being reached although the radiator control correctly regulates the temperature.

5 Taking other heat sources into consideration

Please note that regardless of heating output, the room temperature is also subject to temporary fluctuations or fluctuations due to the time of day. For example, occasional exposure to bright sunlight or reduced ventilation can lead to an increase in room temperature, regardless of the temperature control by the radiator control.

6 Adjusting the measured temperature to room temperature

Since the temperature is measured directly on the radiator control, it may deviate from the actual room temperature, for example in the middle of the room. You can set the temperature difference (offset):

  1. Adjust the temperature measured on the FRITZ!DECT radiator control to the room temperature.