Belimo CRA24 Series User manual

www.belimo.com CRA24-... • en-gb • 2013-05-15 • Subject to changes 1 / 24
Product information CRA24-..
Controller for apartments
CRA24-B3(P)
Room controller with three outputs:
• Supply air device
• Exhaust air device
• Heating valve
CRA24-B1P
3-step switch with one output
• Supply air/exhaust air device

CRA24-..
2 / 24 CRA24-... • en-gb • 2013-05-15 • Subject to changes www.belimo.com
Table of contents
System overview 3
Brief description CRA24-B3(P) 4
Brief description CRA24-B1P 5
Accessories 5
CRA24-B3(P)
Technical data sheet 7
Technical data 7
Safety notes 7
Product features 8
Configuration 8
Electrical installation 8
Operating 9
Operating level 1 – Operation 9
Operating level 2 – Configuration 9
Operating level 3 – Service 9
Functions 10
Introduction 10
Function overview CRA24-B3(P) 10
Control strategy of air volume 11
Control strategy of room temperature 12
Reset MAX → COMF 13
Override functions 13
External temperature sensor (ai1) 14
Analogue outputs 15
CRA24-B1P
Technical data sheet 17
Technical data 17
Safety notes 17
Product features 17
Electrical installation 17
Operating 18
Operating level 1 – Operation 18
Operating level 2 – Configuration 18
Operating level 3 – Service 18
Functions 19
Introduction 19
Function overview CRA24-B1P 19
Air volume control 19
Dimensions, installation, commissioning, service 21
Dimensions [mm] 21
Mechanical installation 21
Electrical installation 21
Design for supply / wire sizing 22
Commissioning / power on behaviour 22
Test and simulation mode 22
Internal function test 23
Control sequence simulation 23
Testing and setting of VAV controller 23

www.belimo.com CRA24-... • en-gb • 2013-05-15 • Subject to changes 3 / 24
Technical data sheet CRA24-..
VAV applications
Single room controller
Water Solutions
General Air Solutions
CRA24-B3 CRA24-B3P CRA24-B1P
Rotary actuators and characterised control valves
Damper actuators
VAV-Compact
OEM product, i.e., VAV controller can be supplied only by the
manufacturer of VAV units
LMV-D3-MP / NMV-D3-MP
R..K + TRD24 / R.. + TR24 / R.. + LR24A
LM24A-MF / NM24A-MF / LM24A-MP / NM24A-MP
Accessories
Fan optimiser fan control (only for VAV systems)
COU24-A-MP
Service tool for VAV-Compact
ZTH-GEN
Setting for VAV-Compact MFT damper actuator
PC-Tool
Connecting cable ZTH-GEN for CRA24-B3(P), diagnostic socket 1/2
ZK1-VAV
System overview CRA24-..

CRA24-..
4 / 24 CRA24-... • en-gb • 2013-05-15 • Subject to changes www.belimo.com
Brief description CRA24-B3(P)
The CRA24-B3(P) room controller has been specially adapted to the requirements of controlled
apartment ventilation. Thanks to its unique functions, e.g. the kitchen and bathroom overrides,
the CRA24-B3(P) is optimised to applications in extremely airtight buildings. The system
combines individual room comfort and minimum energy consumption in an economically
optimised solution.
Pure ventilation systems, either equipped with VAV units or air control dampers, can be
expanded with heating functions as required.
The CR24 controller generation forms the basis of modern single room concepts.
The microprocessor-controlled room temperature controller is perfectly adapted to the BELIMO
actuators for motorised air and water control valves with respect to technology, functionality and
handling.
The CRA24 apartment controllers can be combined or extended with the CR24 room
temperature control range as required (see the separate documentation of the CR24 range).
Override kitchen The kitchen hood fan or even the chimney
extractor system sucks air from the rooms. This
leads to a vacuum and it either becomes difficult
to open doors or doors fly open at you when you
open them.
Controlled by the vapour kitchen hood fan or
chimney ventilator, the CRA24-B3 can minimise
these pressure differences through intelligent
control of the supply air and exhaust air
components.
Override bathroom In energy-efficient buildings with extremely
airtight shells, it is extremely important to draw
off damp air (showers, baths) as quickly as
possible. This helps to minimise damage to
the structural fabric caused by the formation of
mould.
The apartment ventilation can be switched to
maximum air exchange via the light switch or
a humidistat positioned in the corresponding
exhaust air.
Device variants
Standard type CRA24-B3 with user interface (setpoint
adjustment, mode switch and status display). For operation,
see page 9.
Type CRA24-B3P with the same functions as the
CRA24-B3, but with hidden setpoint adjustment.
CRA24-.. Brief description, Accessories

www.belimo.com CRA24-... • en-gb • 2013-05-15 • Subject to changes 5 / 24
Technical data sheet CRA24-..
Brief description CRA24-B1P
The CRA24-B1P is a simple controller that is optimised use in controlled apartment ventilation
systems. Thanks to it simple operation, it is especially suitable for residential units in which
continuous operation of the system is to be ensured.
Together with the downstream VAV units, the air volumes can be adapted individually to the
needs of the user.
The push-button on the controller front can be used to enable the
- COMF → Nominal ventilation
- MIN → Reduced ventilation
- MAX → Intensive ventilation
levels simply and safely. Three LEDs indicate the respectively active level.
Type CRA24-B1P with step switch via push-button.
Accessories
Mechanical accessories Type Description
CRZA-A Spare cover without user interface
CRZW Spare baseplate
Brief description, Accessories CRA24-..

CRA24-..
6 / 24 CRA24-... • en-gb • 2013-05-15 • Subject to changes www.belimo.com
CRA24-..

www.belimo.com CRA24-... • en-gb • 2013-05-15 • Subject to changes 7 / 24
Technical data sheet CRA24-..
Technical data
Electrical data Nominal voltage AC 24V 50/60 Hz
Dimensioning 3 VA, without actuators
Power supply range AC 19.2 … 28.8V
Connections Terminal block 1 … 3: 2.5 mm2
Terminal block 4 … 12: 1.5 mm2
Functional data Control characteristics P
– P-Band Selectable: 1.5 K or 3.0 K
External temperature sensor (ai1) Type NTC, 5 k�, power supply range 10 … 45°C
e.g. Belimo Type TFK
Setpoint Adjustment range 15 … 36°C (Default 21°C)
– Energy hold off (EHO) Heating –2 K
Room temperature (frost protection) 14°C
Max. room temperature monitoring 28°C
Operation
– Mode switch and status display (LED) COMF (green) – MIN (orange) – MAX (red)
– Rotary knob for setpoint adjustment 30 … 70% air / ±3 K temperature
Communication connection for field devices 2 x PP (for PC-Tool, ZTH-GEN, etc.)
Inputs 1 x analogue, 3 x digital
– External temperature sensor (ai1) Type NTC, 5 k�, power supply range 10 … 45°C
– Digital inputs (di1, di2, di3) Contact load 10 mA
Output 3 x analogue or digital
– Supply air VAV system output (ao1) 2 … 10V, max. 5 mA
– Exhaust air VAV system output (ao2) 2 … 10V, max. 5 mA
– Heating output (ao3) 2-point / 3-point, AC 24V, source current max. 0.5 A
/ 10 VA (optimised for actuators with approx. 150 s
running time)
Norms and Standards Protection class III Safety extra-low voltage
Degree of protection IP30 (EN 60529)
Mode of operation Type 1 (EN60730-1)
Software class A (EN 60730-1)
EMC CE according to 2004/108/EC
Ambient conditions
– Operation 0 … +50°C / 20 … 90% r.h. (non-condensing)
– Transport and storage –25 … +70°C / 20 … 90% r.h. (non-condensing)
Dimensions / weight Dimensions (H x W x D) 99 x 84 x 32 mm
Weight 105 g
Housing colours Baseplate NCS2005-R80B light grey (corresponds approximately
to RAL 7035)
Cover RAL 9003 Signal white
Room controllers for controlled apartment
ventilation with three outputs:
• Analogue output ao1: Supply air device
– VAV unit or damper actuator
• Analogue output ao2: Exhaust air
device
– VAV unit or damper actuator
• Output ao3: 2-point (on/off) or 3-point
signal for a heating valve
Safety notes
!
• The controller is not allowed to be used outside the specified field of application, especially
not in aircraft or in any other airborne means of transport.
• It may only be installed by suitably trained personnel.
Legal regulations and regulations issued by authorities must be observed during installation.
• The device does not contain any parts that can be replaced or repaired by the user.
• The device contains electrical and electronic components and is not allowed to be disposed
of as household refuse. All locally valid regulations and requirements must be observed.
Device variant
Type CRA24-B3P, same functions as the CRA24-B3,
but with a hidden user interface.
Technical data sheet CRA24-B3(P)

CRA24-..
8 / 24 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
12910 11 678
3412 5
AC 24 V
~
NTC
CRA24-B3(P)
ai/di1 di2 di3
ao1ao2ao3 U51U52
T
Inputs Outputs
3ai1 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

www.belimo.com CRA24-... • en-gb • 2013-05-15 • Subject to changes 9 / 24
Technical data sheet CRA24-..
2 1
Mode switch and status display
One of three operating modes can be selected:
• COMF – Comfort-oriented operating mode
If the external control signals permit this, the room is maintained
in the comfort state using the selected control strategy. All control
functions are enabled.
• MIN – Minimum operating mode
The air volume is maintained to the minimum value that is set at the
VAV controller. The heating valve regulates to the selected setpoint.
Advantages: Energy saving mode during short absences.
• MAX – Maximum operating mode
The air volume is regulated to the maximum value that is set at the
VAV controller. The heating valve is regulated to the set setpoint.
Advantages: Maximum air exchange, e.g. during a party or fondue
evening.
Connecting terminals measuring points
Measuring points for all connection terminals (also during operation).
Internal function test
A comprehensive internal function test can be started using the mode
switch which enables a test of the controller including the nominal
voltage (AC 24 V). The three LEDs (status display) display the statuses
of the voltage level.
Control sequence simulation
The connected actuators as well as the control sequences can be
simulated independent of the room temperature using the rotary knob
for the setpoint adjustment.
ZTH-GEN / PC-Tool connection
The diagnostic sockets 1 and 2 help in PP communication with the
connected Belimo MFT actuators or VAV-Compact controllers. This
makes physical access to the field devices unnecessary.
Operation level 1 – Operation Operating mode / Setpoint
DIP switch for configuration
DIP switches 1 to 6
Basic setpoint adjustment of the room temperature WH (heating
setpoint)
Potentiometer 15 … 36°C (Default 21°C)
Label for settings
Retaining the used settings
(DIP switch and basic setpoint).
Operation level 2 – Configuration Application / Parameters
Operation level 3 – Service Test / Simulation
Rotary knob for setpoint adjustment (CRA24-B3 only)
• Control strategy air volume of 30 … 70 %
• Control strategy room temperature ±3 K
Mode switch
• MAX
• MIN
• COMF
Status display
• MAX (red)
• MIN (orange)
• COMF (green)
Order-Nr.
CRA24-Bxx
W
H
U5 /
2
U5 /
1
1 2 3 4 5 6
O N
OF F
2 1
3 6
1 5
Measuring points
Connecting terminals
ZTH-GEN / PC-Tool connection
Internal function test
Basic setpoint adjustment
Room temperature
DIP switch for configuration
Label for settings
1
2
3
4
5
6
7
8
Rotary knob for
Control sequence simulation
9
10
11
12
Hidden rotary knob for setpoint
adjustment (CRA24-B3P only)
Operating CRA24-B3(P)

CRA24-..
10 / 24 CRA24-... • en-gb • 2013-05-15 • Subject to changes www.belimo.com
Introduction
The control functions of the CRA24-B3(P) define the behaviour of the control outputs or
influence the current setpoint.
The operation can be automated and the comfort and energy saving potential can be increased
using the appropriate sensor system on the input side.
The relevant functions have been individually described below
We usually differentiate between two different control strategy that have been described below in
more detail.
Function overview
Supply AC 24V / 50/60 Hz
Application – Air volume or room temperature control in comfort zone
– Internal temperature sensor (Type NTC, Power supply range 10 … 45°C)
– Setpoint (setting range 30 … 70% air / 15 … 36°C temperature)
Operating – Mode selection switch: COMF – MIN – MAX
– Mode indication LED: COMF – MIN – MAX
– Setpoint adjustment rotary knob (CRA24-B3P hidden): 30 … 70% air / ±3 K temperature
4 inputs – Override kitchen
– Override bathroom
– Energy hold off (EHO)
– External temperature sensor (Type NTC 5 kΩ, operating range 10 … 45°C)
3 outputs – 2 … 10 V system output for supply air: Belimo VAV controller, damper actuator
– 2 … 10 V system output for exhaust air: Belimo VAV controller, damper actuator
– 2-point (thermal actuator) / 3-point heating output
Functions – Control characteristics: P
– P-Band, switchable
– Control strategy can be switched (air volume / room temperature)
– Air sequence can be switched (cooling / heating)
– Room temperature monitoring (min and max)
– Internal function test with nominal voltage test
– Commissioning mode with simulation of output and sequence
– Diagnostics of VAV controllers using an integrated PC-Tool connection
Installation Surface mounting with flush-mounted or surface-mounted connection
Application documentation
A comprehensive documentation with specific applications has been provided for the CRA24-3(P)
controller and this documentation is constantly updated.
CRA24-B3(P) Functions

www.belimo.com CRA24-... • en-gb • 2013-05-15 • Subject to changes 11 / 24
Technical data sheet CRA24-..
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.
Settings with ZTH-GEN The operating volumetric flow setting min / max of the VAV controllers can be modified/checked
with the help of the ZTH-GEN. Connection to diagnostic sockets 1 and 2.
Application with damper actuator instead of
VAV controllers
Use of damper actuators is usually possible but it must still be taken into account that this
application cannot detect and regulate pressure changes in the air duct system (pre-
pressure-dependent operation).
Type: LM24A-MF / NM24A-MF
The MIN/MAX levels of the MF actuator can be programmed with the ZTH-GEN service tool or
the Belimo PC-Tool and then be loaded in L/NM24A-MF.
Configuration
1 2 3 4 5 6
ON
OFF
The "Air volume" control strategy is configured with the help of DIP switch 2 = OFF.
Operating mode COMF Operating mode MIN Operating mode MAX
• The air volume can be set in the range of 30 …
70% of the operating volume
current range min … max programmed on the
VAV controller.
Setting of the VAV controller (example):
– min 50 m3/h
– max 100 m3/h
– Setting range of the rotary knob: 65 … 85 m3/h
• The heating valve is not supported by the air
volume control strategy
• Air volume setting:
– CRA24-B3 → Rotary knob on the controller
front
– CRA24-B3P → Potentiometer under the front
cover
• The connected VAV units are set to the
minimum air volume (min) selected on the
controller.
• The heating valve is not supported by the air
volume control strategy
• The connected VAV units are set to the
maximum air volume (max) selected on the
controller.
• The heating valve is not supported by the air
volume control strategy
Reset MAX → COMF
with DIP switch 4 (see page 13):
• DIP switch 4 = OFF:
Manual reset
• DIP switch 4 = ON:
Automatic reset after one hour
Y [V]
10
2
4.4
7.6
0
ao1/ao2
Y [V]
10
2
0
ao1/ao2
Y [V]
10
2
0
ao1/ao2
Max
Comfort
Min
COMF
Max
Minimum
Min
COMF
Max
Maximum
Min
COMF
Volumetric flow
max / OPEN
70%
30%
Vmin
CLOSED
Volumetric flow
max / OPEN
min
CLOSED
Volumetric flow
max / OPEN
min
CLOSED
Note
The MIN / MAX levels cannot be changed when
using an -SR standard actuator (mode 0 … 10V),
e.g. LM24A-SR!
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
:
Functions CRA24-B3(P)

CRA24-..
12 / 24 CRA24-... • en-gb • 2013-05-15 • Subject to changes www.belimo.com
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 selected parameters.
Configuration
1 2 3 4 5 6
ON
OFF
The "Room temperature" control strategy is configured with the help of DIP switch 2 = ON.
Operating mode COMF Operating mode MIN Operating mode MAX
• The temperature setpoint can be selected
between 15°C … 36°C on the "Basic setpoint
adjustment" potentiometer under the cover
(operation level 2).
• Correction of the setpoint:
– CRA24-B3 via the rotary knob on the controller
front
– CRA24-B3P potentiometer under the front
cover
•The reference signal ao1/ao2 on the
VAV controller depends on the selected
sequence (cooling / heating).
DIP switch 3: OFF = cooling / ON = heating
• The heating valve regulates the set setpoint.
• The connected VAV controllers are set to the
minimum air volume (min) selected on the
controller.
• The heating valve regulates to the selected
setpoint.
• The connected VAV controllers are set to the
maximum air volume (max) selected on the
controller.
• The heating valve regulates to the selected
setpoint.
Reset MAX → COMF
with DIP switch 4 (see page 13):
• DIP switch 4 = OFF:
Manual reset
• DIP switch 4 = ON:
Automatic reset after one hour
Variant for 2-point heating: DIP switch 6 = OFF Variant for 2-point heating: DIP switch 6 = OFF Variant for 2-point heating: DIP switch 6 = OFF
Y [V]
tR [°C]
10
2
0
XP HXP C
ao1/ao2ao3/1
ao1/ao2
wHwC
Y [V]
tR
[°C]
10
2
0
Xd
ao3/1 ao1/ao2
wH
Y [V]
tR
[°C]
10
2
0
Xd
ao3/1
wH
ao1/ao2
Variant for 3-point heating: DIP switch 6 = ON Variant for 3-point heating: DIP switch 6 = ON Variant for 3-point heating: DIP switch 6 = ON
Y [V]
tR
[°C]
10
2
0
XP HXP C
ao1/ao2ao3
ao1/ao2
wHwC
Y [V]
tR [°C]
10
2
0
X
pH
ao3 ao1/ao2
wH
Y [V]
tR [°C]
10
2
0
ao3
wH
ao1/ao2
X
pH
Max
Comfort
Min
COMF
Max
Minimum
Min
COMF
Max
Maximum
Min
COMF
Volumetric flow
max
min
CLOSED
Volumetric flow
max
min
CLOSED
Volumetric flow
max
min
CLOSED
Heating Cooling Heating Heating
1 2 3 4 5 6
ON
OFF
Cooling / Heating Cooling / Heating
Volumetric flow
max
min
CLOSED
Heating Cooling
Volumetric flow
max
min
CLOSED
Heating Cooling / Heating
Volumetric flow
max
min
CLOSED
Heating Cooling / Heating
CRA24-B3(P) Functions

www.belimo.com CRA24-... • en-gb • 2013-05-15 • Subject to changes 13 / 24
Technical data sheet CRA24-..
Functions CRA24-B3(P)
Reset MAX → COMF
1 2 3 4 5 6
123456
ON
OFF
DIP switch 4 = OFF:
The reset from the manually selected operating mode MAX is accomplished solely by means of
the mode switch on the controller front.
1 2 3 4 5 6
1 2 3 4 5 6
ON
OFF
DIP switch 4 = ON:
The reset from the manually selected operating mode MAX will be done automatically after a
one-hour delay. The operating mode can also be changed manually during this time.
Override functions
If several override functions are switched on, the one with the highest priority is activated.
Priority 1: Frost
(Building protection)
This function becomes active if the room temperature falls below 14°C room protection
temperature (frost protection function).
Component Air volume Room temperature
Supply air (ao1) 100% = max 100% = max
Extract air (ao2) 100% = max 100% = max
Heating valve (ao3) OPEN OPEN
Priority 2: Kitchen (di2)
(Chimney extractor system)
In order to minimise the pressure differences within rooms, the air balance can be regulated
using the kitchen hood fan or the chimney extractor.
Component Air volume Room temperature
Supply air (ao1) 100% = max 100% = max
Extract air (ao2) 0% = min 0% = min
Heating valve (ao3) No function Control mode
12
34
AC 24 V
CRA24-B3
ai/di1 di2
12
di3
T
~
Priority 3: Bathroom (di3) In order to remove humid air or odours from the house, the VAV controllers / air dampers can be
switched to the maximum volumetric flow, for example, via the light switch in the bathroom or a
humidistat.
Component Air volume Room temperature
Supply air (ao1) 100% = max 100% = max
Extract air (ao2) 100% = max 100% = max
Heating valve (ao3) No function Control mode
12
34
AC 24 V
CRA24-B3
ai/di1 di2
12
di3
T
~
Kitchen
Bathroom
Max
Boost
Min
COMF
Max
Boost
Min
COMF
Max
Boost
Min
COMF

CRA24-..
14 / 24 CRA24-... • en-gb • 2013-05-15 • Subject to changes www.belimo.com
Override functions (continued)
Priority 4: Energy hold off (di1) In order to prevent undesired energy consumption in the event of long periods of absence,
the VAV controllers / air dampers are closed and the heating unit is operated with a reduced
setpoint.
Component Air volume Room temperature
Supply air (ao1) CLOSED CLOSED
Extract air (ao2) CLOSED CLOSED
Heating valve (ao3) No function Reduced control mode (setpoint – 2K offset)
12
34
AC 24 V
NTC
CRA24-B3
ai/di1 di2
12
di3
T
~
EHO
Max
Boost
Min
COMF
Forced ventilation
Holiday mode
During the energy hold off, the system is switched on for 30 minutes three times a day. The start
times are calculated by CRA24-B3 and cannot be changed.
Component Air volume Room temperature
Supply air (ao1) 100% = max 100% = max
Extract air (ao2) 100% = max 100% = max
Heating valve (ao3) No function Reduced control mode (setpoint – 2K offset)
Maximum temperature monitoring
1 2 3 4 5 6
ON
OFF
The room temperature can be monitored to a maximum value of 28°C.
This function must be enabled via DIP switch 5 = ON.
Component Air volume Room temperature
Supply air (ao1) 100% = max 100% = max
Extract air (ao2) 100% = max 100% = max
Heating valve (ao3) No function CLOSED
External temperature sensor (ai1)
An external NTC temperature sensor can be connected at analogue input ai1. Sensor type: NTC
5k (5 kΏ) e.g. Belimo TFK.
Typical applications
• Temperature measurement in the exhaust air duct for recording the average room temperature.
• More flexible positioning of the sensor for recording the room temperature
12
34
AC 24 V
CRA24-B3
ai/di1 di2
12
di3
T
~
EHO
Note:
• The controller detects the connection of an
external sensor automatically. Additional settings
are not required.
• The simultaneous use of an energy hold off
switch at di1 is possible, although the system
switches over to the internal sensor in such cases
(see also "Energy hold off"). This means that
the current room temperature is monitored for
building protection.
External NTC temperature
sensor
External NTC
temperature sensor
CRA24-B3(P) Functions

www.belimo.com CRA24-... • en-gb • 2013-05-15 • Subject to changes 15 / 24
Technical data sheet CRA24-..
Analogue outputs
VAV controller connection Due to the override function, it is mandatory that the supply and exhaust air control devices be
connected as follows:
– Supply air: System output "ao1" (terminal 6), diagnostic connection "U5 / 1" (terminal 7)
– Exhaust air: System output "ao2" (terminal 11), diagnostic connection "U5 / 2" (terminal 8)
12910 11 678
3412
CRA24-B3
ai/di1 di2 di3
ao1ao2ao3 U51U52
AC 24 V
T
~
12 35
YU
T
~
12910 11 678
3412
CRA24-B3
ai/di1 di2 di3
ao1ao2ao3 U51U52
AC 24 V
T
~
12 35
YU
T
~
Heating valve connection
1 2 3 4 5 6
ON
OFF
Heating valves can be controlled using a 2-point or a 3-point actuator. This selection is made
using DIP switch 6. OFF = 2-point (thermo) / ON = 3-point
12910 11 678
3412
CRA24-B3
ai/di1 di2 di3
ao1ao2ao3 U51U52
AC 24 V
T
~
12
T
~
12910 11 678
3412
CRA24-B3
ai/di1 di2 di3
ao1ao2ao3 U51U52
AC 24 V
T
~
123
T
Supply air Exhaust air
Thermo valve actuator 3-point valve actuator
Functions CRA24-B3(P)

CRA24-..
16 / 24 CRA24-... • en-gb • 2013-05-15 • Subject to changes www.belimo.com
CRA24-..

www.belimo.com CRA24-... • en-gb • 2013-05-15 • Subject to changes 17 / 24
Technical data sheet CRA24-..
Technical data
Electrical data Nominal voltage AC 24V 50/60 Hz
Dimensioning 2 VA, without actuators
Power supply range AC 19.2…28.8V
Connections Terminal block 1 … 3: 2.5 mm2
Functional data Operating
– Mode switch and status display (LED) COMF (green) – MIN (orange) – MAX (red)
– Hidden rotary knob for setpoint adjustment 30…70% air
Output 1x analogue
– VAV system output (ao1) 2…10V, max. 5 mA
Norms and Standards Protection class III Safety extra-low voltage
Degree of protection IP30 (EN 60529)
Mode of operation Type 1 (EN60730-1)
EMC CE according to 2004/108/EC
Ambient conditions
– Operation 0…+50°C / 20… 90% r.h. (non-condensing)
– Transport and storage –25…+70°C / 20…90% r.h.
(non-condensing)
Dimensions / weight Dimensions (H x W x D) 99 x 84 x 32 mm
Weight 105 g
Housing colours Baseplate NCS2005-R80B-light grey
(corresponds approx. to RAL 7035)
Cover RAL 9003 Signal white
3-step switch for controlled apartment
ventilation with one output:
• Analogue output ao1: Supply air/exhaust
air device
– VAV unit or damper actuator
Safety notes
!
• The controller is not allowed to be used outside the specified field of application, especially
not in aircraft or in any other airborne means of transport.
• It may only be installed by suitably trained personnel.
Legal regulations and regulations issued by authorities must be observed during installation.
• The device does not contain any parts that can be replaced or repaired by the user.
• The device contains electrical and electronic components and is not allowed to be disposed
of as household refuse. All locally valid regulations and requirements must be observed.
Product features
Air volume control The air volume can be pre-selected and set to minimum, variable (dial: 30 … 70%) and
maximum using the push-button and the hidden rotary knob under the controller front. This is
especially suitable for applications requiring a defined air exchange.
Electrical installation
Wiring diagram
Notes
• Connection via safety isolating transformer.
• Parallel connection of other actuators possible.
Note the performance data.
!
1 2 3
5
123
CRA24-B1P
supply air VAV-controller
extract air VAV-controller
ao1
AC 24 V
~
T
~U
γ
T
5
123
~U
γ
T
Technical data sheet CRA24-B1P

CRA24-..
18 / 24 CRA24-... • en-gb • 2013-05-15 • Subject to changes www.belimo.com
2 1
Mode switch and status display
One of three operating modes can be selected:
• COMF – Nominal ventilation
The room is maintained at comfort zone status.
• MIN – Reduced ventilation
The air volume is regulated to the minimum value that is set at the
VAV controller.
Advantages: Energy saving mode during short absences.
• MAX – Intensive ventilation
The air volume is regulated to the maximum value that is set at the
VAV controller.
Advantages: Maximum air exchange, e.g. during a party or fondue
evening.
Connecting terminals measuring points
Measuring points for all connection terminals (also during operation).
Operation level 1 – Operation Operating mode / Setpoint
Operation level 2 – Configuration
Operation level 3 – Service Test
Mode switch
• MAX
• MIN
• COMF
Status display
• MAX (red)
• MIN (orange)
• COMF (green)
Order-Nr.
CRA24-Bxx
Measuring points
Connecting terminals
Label
1
2
3
Hidden rotary knob for setpoint
adjustment (air volume 30...70%)
CRA24-B1P Operating

www.belimo.com CRA24-... • en-gb • 2013-05-15 • Subject to changes 19 / 24
Technical data sheet CRA24-..
Introduction
The CRA24-B1P is a 3-step switch without control functions or overrides.
The various operating modes are set by pressing the button on the front.
The corresponding functions are described in detail in the following.
Function overview
Supply AC 24V / 50/60 Hz
Application – Air volume control in the comfort zone
Operation – Mode selection switch: COMF – MIN – MAX
– Mode indication LED: COMF – MIN – MAX
– Hidden rotary knob for setpoint adjustment: 30…70% air
1 output – 2…10V system output: Belimo VAV controller, damper actuator
Functions – Air volume control
Installation Surface mounting with flush-mounted or surface-mounted connection
Air volume control
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 under the controller front. This is especially
suitable for applications requiring a defined air exchange.
Settings with ZTH-GEN The operating volumetric flow setting min / max of the VAV controllers can be modified/checked
with the help of the ZTH-GEN.
Application with damper actuator instead of
VAV controllers
Use of damper actuators is usually possible but it must still be taken into account that this
application cannot detect and regulate pressure changes in the air duct system (pre-
pressure-dependent operation).
Type: LM24A-MF / NM24A-MF
The MIN/MAX levels of the MF actuator can be programmed with the ZTH-GEN service tool or
the Belimo PC-Tool and then be loaded in L/NM24A-MF.
Note
The MIN / MAX levels cannot be changed when
using an -SR standard actuator (mode 0 … 10V),
e.g. LM24A-SR!
Operating mode COMF (nominal ventilation) Operating mode MIN (reduced ventilation) Operating mode MAX (intensive ventilation)
• The air volume can be set in the range of
30…70% of the operating volume
current range min…max programmed on the VAV
controller.
Setting of the VAV controller (example):
– min 50 m3/h
– max 100 m3/h
– Setting range of the rotary knob: 65…85 m3/h
• Air volume setting:
– CRA24-B1P → Potentiometer under the front
cover
• The connected VAV units are set to the
minimum air volume (min) selected on the
controller.
• The connected VAV units are set to the
maximum air volume (max) selected on the
controller.
Y [V]
10
2
4.4
7.6
ao1
Y [V]
10
2ao1
Y [V]
10
2
ao1
Max
Comfort
Min
COMF
Max
Minimum
Min
COMF
Max
Maximum
Min
COMF
Volumetric flow
max
70%
30%
min
Volumetric flow
max
min
Volumetric flow
max
min
Functions CRA24-B1P

CRA24-..
20 / 24 CRA24-... • en-gb • 2013-05-15 • Subject to changes www.belimo.com
CRA24-..