How the dew-point control works

The function of the dew point control is explained below. Temperature and humidity sensors measure the indoor and outdoor temperature and humidity. The control unit records and evaluates these readings. When you set up the control unit, you define the following parameters:

• minimum and maximum temperature for the interior 
• minimum humidity (also called target humidity) for the interior
• Difference in absolute humidity between inside and outside
• other settings such as time, working time, ventilation time, etc. (explanations of these settings are listed in detail in the operating instructions)

The control unit ventilates when it is drier outside than inside to dry the room. Otherwise, the message “It is not dry enough outside” appears. The absolute humidity is used for this, not the relative humidity. You can see the absolute humidity on the last line of the display. In addition, other conditions must be met for the ventilation to be switched on:

The indoor temperature must be within the set limits. The minimum and maximum temperatures you set are crucial for this. Otherwise, the message “Minimum temperature reached” or “Maximum temperature reached” appears. If the indoor temperature is outside these limits, the device can only ventilate if the outdoor temperature is such that ventilating brings the indoor temperature closer to the set limits (heating or cooling the room). Example 1: Indoor temperature: 18 °C, minimum temperature: 20 °C, maximum temperature: 27 °C. The indoor temperature is outside the limits. Ventilation can only take place when the outdoor temperature is greater than 18 °C so that the room can be heated and thus brought closer to 20 °C.

Example 2: Indoor temperature: 28 °C, minimum temperature: 20 °C, maximum temperature: 27 °C. The indoor temperature is outside the limits. Ventilation can only take place when the outdoor temperature is lower than 28 °C so that the room can be cooled and thus brought closer to 27 °C. The relative humidity inside must be greater than the set target humidity. Otherwise, the message “Target humidity reached” appears. In addition, the current time must be within the working time limits you have set. Otherwise, the message “Outside working hours” will appear. If the conditions are met, the device switches the ventilation on. This continues for as long as the conditions remain met, or until the set ventilation time has elapsed. Regardless of why the ventilation is switched off again, the message “Fan pause” always appears on the display. Only after the pause are all conditions checked again and ventilation can begin again. Example: absolute humidity inside: 12, absolute humidity outside: 10.8, difference: 1.0, ventilation: off.

Since the absolute humidity inside is greater than the absolute humidity outside plus the difference (12 > 11.8), the ventilation is now switched on (provided the other conditions are also met). It is only switched off at the end of the ventilation time or when the absolute humidity outside is at least as high as the absolute humidity inside
(difference for switching off is always 0). After the pause, the device is only switched on again when the difference of 1.0
is maintained. The cycle from this example then starts again.