The night cooling effect and “natural bypass cooling“ is strongly influenced by the temperature differences between
outside air/supply air and room air, the flow rate, the shade and the required cooling loads. Bypass cooling will never
replace air conditioning!
– Bypass functional description
If the ventilation unit is supplied with system voltage, the bypass will close completely. The bypass will open if the all of
the following conditions are met:
Condition 1:
The room temperature is higher than the set target supply air temp. (factory setting: 21 °C).
Condition 2: The outside air temperature is higher than the set outside air temperature limit (factory setting: 15 °C).
The temperature of the outside air temperature limit, can be changed on the controller > Service menu:
“Bypass settings“.
Condition 3: The room temperature is higher than the outside air temperature.
The bypass is closed if one of the aforementioned conditions is no longer met!
3.2.13 Demand-driven regulation of ventilation units through CO
2
and humidity sensors
The ventilation unit has the connection option for a sensor (CO
2
or humidity). The sensor is connected directly to the
unit motherboard pursuant to the wiring diagram.
The CO
2
control system monitors the CO
2
concentration in the room and ensures increased ventilation at higher con-
centrations to prevent, for example, signs of fatigue, the lack of concentration or headaches. The CO
2
sensor is deac-
tivated on the service menu of the controller when delivered from the factory.
The humidity control ensures increased ventilation at higher levels of indoor humidity (% RH) for the removal of moisture
to counteract damage to the building material. The humidity controller is deactivated when delivered from the factory.
In order to activate the sensor controller, the CO
2
sensor or humidity sensor must be activated in service menu 08-AQS
Sensor of the comfort controller following connection to the main circuit board.
Furthermore, the ventilation unit must be set to DCV mode.
The unit airflow rate is controlled automatically depending on the CO
2
concentration or the relative humidity. The airflow
rate is automatically increased with the increase of the respective sensor value. If the set limit value is exceeded, the
ventilation unit will work at max. flow rate capacity.
3.2.14 Fan calibration
The maximum operating point of the ventilation unit is determined during fan calibration. in this respect, the ventilation
unit runs at 100% ventilator capacity for a defined period of time. The maximum achievable flow rate and the corres-
ponding static pressure in the ductwork is shown as a result of the fan calibration.
The calibration can be activated on the controller > Service menu 04: “Fan calibration“ (see also page 19).
The calibra-
tion takes around 3-5 minutes before the result is shown on the display!
If a lower operating point is desired, the value can be set individually after the calibration in menu 04 Fan calibration
using the
+/-
buttons (see page 19, service menu 04 Fan calibration).
In the context of starting up and adjustment of the ventilation unit, the ventilator calibration must be carried
out before adjusting the ventilation unit! All control dampers should be pre-set to the desired target value, all
valves should be completely opened.
3.2.15 Modbus
The fan unit can also be controlled via the following interfaces:
•
Modbus TCP
•
Modbus RTU RS 485 via A1 25-26
NOTE
+
ATTENTION
m
12
Central Ventilation Units KWL EC.. D Pro/WW
Installation and Operating Instructions
EN
