CRA24-..
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CRA24-... • en-gb • 2013-05-15 • Subject to changes
www.belimo.com
Product features
Air volume control strategy
The air volume can be pre-selected and set to minimum, variable (dial: 30 … 70%) and
maximum using the push-button and the rotary knob on the controller front. This is especially
suitable for applications requiring a defined air exchange. The heating output is not available.
Room temperature control strategy
The desired comfort temperature can be selected using the rotary knob. The room controller
controls the air volumes as well as the heating valve on the basis of the set parameters.
Override kitchen
Pressure differences caused by the kitchen hood fan or the chimney extraction system are
balanced out largely by reducing the exhaust air volume.
Override bathroom
Volume currents are increased to the maximum air change, e.g. in order to draw off humid air
from rooms as quickly as possible.
Energy hold off (EHO)
The room is controlled in the energy saving mode, i.e. the VAV units are closed and the heating
setpoint is lowered to the value for the room protection function during long periods of absence,
for example.
Room protection (Frost)
If the current room temperature falls below 14°C, the room protection function is activated.
External temperature sensor
An external temperature sensor can be connected to the analogue input ai1, e.g. in the exhaust
air duct for calculating the average room temperature.
Electrical installation
Wiring diagram
1 2 9 10 11 6 7 8
3
4 12
5
AC 24 V
~
NTC
CRA24-B3(P)
ai/di1
di2 di3
ao1
ao2
ao3
U5
1
U5
2
T
Inputs
Outputs
3
ai1 External temperature sensor
6
ao1 System output VAV controller supply air
di1 Energy hold off (EHO)
9/10 ao3 2-point / 3-point output heating
4
di2 Override kitchen
11
ao2 System output VAV controller exhaust
air
5
–
Not used
Other connections
12 di3 Override bathroom
7
PP1 Diagnostic socket VAV controller supply
air
8
PP2 Diagnostic socket VAV controller
exhaust air
Notes
• Connection via safety isolating transformer.
• Parallel connection of other actuators possible.
Note the performance data.
!
Configuration
Configuration
DIP
Default settings
1
P-Band normal
P-Band wide
2
Air volume control strategy
Room temperature control strategy
3
Control sequence for air cooling
Control sequence for air heating
4
Reset MAX → COMF
Off
Reset MAX → COMF
1 h
5
Max. temp. monitoring
Off
Max. temp. monitoring
On
6
Definition of heating output (ao3)
2-point actuator
Definition of heating output (ao3)
3-point actuator
1
2
3
4
5
6
ON
OFF
Note
The functions are described in detail on pages 10
to 15.
CRA24-B3(P)
Technical data sheet
