If the
Return air temperature maximum limit is exceeded by the amount x, the set point (for
cascade control, the set point of the exhaust air or room temperature) is reduced by the
amount x multiplied with the
Return air temperature limit factor.
4
x = Actual return air temperature – Return air temperature maximum limit
Note!
The permissible return air temperature maximum limit depends on the outdoor tem-
perature (see Fig. )
4
Supply air temperature set point
calculated
=
Supply air temperature set point – x · Return air temperature limit factor
The supply air temperature limit has priority.
Parameters
WE
Range of values
Return air temperature minimum limit
20 °C
0°C up to return air flow temp. maximum limit
Return air flow temperature maximum li-
mit, coordinates 1 and 2
70 °C
Return air temperature minimum limit up to 100 °C
Return air temperature limit factor
1
0 to 10
Outdoor temperature coordinate 1
5 °C
–50 to 20 °C
Outdoor temperature coordinate 2
20 °C
–50 to 20 °C
6.5
Sustained room temperature
If a room temperature sensor is connected, the
Sustained room temperature is monitored
when the system is in the reduced operation mode. If the room temperature falls below this
limit value, at first the system start-up function is initiated. Then the supply air temperature is
controlled constantly to the set point
Supply air temperature maximum limit (minus 1 °C). If
the room temperature has reached the
Sustained room temperature (plus 2 °C), the sustained
room temperature function and usually the operation of the entire system is ended.
Functions
WE
Configuration
Sensor F5, room temperature
Fb5 = ON
Parameters
WE
Range of values
Room sustained temperature
15 °C
0 to 20 °C
Supply air temperature minimum limit
26 °C
Supply air temperature minimum limit up to 50 °C
EB 5477 EN
55
Control functions