Belimo CR24 Series User manual

Product information CR24-..
www.belimo.com
Product information S4-CR24-.. • en • v2.2 • 01.2024 • Subject to changes
CR24-.. Single room controllers
Table of contents
Overview of the system 2
Overview of functions 3
Technical data sheets
CR24-B1 / CR24-A1 Single room controllers
CR24-B2 / CR24-A2 Single room controllers
CR24-B2E / CR24-A2E Single room controllers
CR24-B3 / CR24-A3 Single room controllers
5
7
9
13
Operation 15
Functions
Setpoint calculation
Energy hold off / Stand-by / VAV-function
Electric air heater / External temperature sensor / Supply air temperature limitation
External setpoint shift / Air flush
Change-over
Boost
Chilled ceiling
Rolling start / Excess temperature protection / Step control
17
18
19
20
21
22
23
24
Dimensions, Installation, commissioning, service 25

Overview of the system
CR24-..
2www.belimo.com
Product information S4-CR24-.. • en • v2.2 • 01.2024 • Subject to changes
VAV applications
Single room controllers
Water applications
Air applications
CR24-B1 CR24-B2E CR24-B3CR24-B2
Compact Universal
Rotary actuators and
characterised control valves
Damper actuators

Overview of functions CR24-..
www.belimo.com 3
Product information S4-CR24-.. • en • v2.2 • 01.2024 • Subject to changes
Brief description
The newly developed CR24-.. controller generation provides the foundation for modern single
room concepts.
The technology, functionality and handling of the new microprocessor-controlled room tem-
perature controllers are perfectly adapted to the Belimo actuators for motorised air and water



controlling the room climate and reducing energy consumption. The controllers can be used
in both pure VAV and combined systems with 2- and 4-pipe water applications (radiators, air
heaters/coolers, heated/chilled ceilings).
Device variants
Standard CR24-B.. type with operating ele-
ments (setpoint adjustment, mode switch and
status indication). For operation, refer to page
15.
Type CR24-A..: same functionality as the
CR24-B.. but without operating elements.
Notes
Unless otherwise expressly mentioned, all
references contained in this document to the
CR24-B.. also apply to the CR24-A...
Accessories
Type Description
Mechanical accessories CRZA-A Spare cover for A-types
CRZA-B Spare cover for B-types (with operating elements)
CRZW Spare wall socket, fits all types

Overview of functions
CR24-..
4www.belimo.com
Product information S4-CR24-.. • en • v2.2 • 01.2024 • Subject to changes
Overview of CR24-B.. functions CR24-B1 CR24-B2 CR24-B2E CR24-B3
Power supply AC 24 V / 50/60Hz • • • •
Application / Temperature range
– Room temperature control in comfort zone ••••
– Internal temperature sensor (Type NTC, measuring range 10...45°C) ••••
– Setpoint (adjustment range 15...36°C) ••••
Operation (CR24-B.. only) ••••
– Mode selection Switch: AUTO – ECO – MAX ••••
– Mode indication LEDs: AUTO – ECO – MAX ••••
– Setpoint adjustm. Rotary knob: ±3 K ••••
Inputs Number 4 5 5 5
– Energy hold off • • • •
– Stand-by •1) •••
– Changeover •1) •2)
– Chilled ceiling with dew point limiting and changeover •2)
– Air flush • •
– Boost ••2)
– External temperature sensor (Type NTC, measuring range 10...45°C) • • • •
– External setpoint shift 0...10 V • • • •
Outputs Number 1 2 3 3
– (0)2...10 V system output for Belimo VAV controller or changeover •3)
– (0)2...10 V system output for Belimo VAV controller •••
– Heating output 3-point •••
– Electric air heater 1...3 stages or on/close radiator valve •
– Heating or cooling output, changeover 0...10 V •4)
Functions
– Control characteristics P P P P / PI
– P-band switchable • • • •
– Boost function Vmax or temperature, selectable •
– Boost function temperature •
– Volume increase in heating mode, selectable • • •
– Internal function test, including nominal voltage test • • • •
  • • • •
– VAV controller diagnosis via integrated PC-Tool connection • • • •
Mounting
Surface mounting with flush-mounted or surface-mounted connection • • • •
Housing colors
Baseplate NCS 2005-R80B light grey
(corresponds approx. to RAL 7035)
Cover RAL 9003 signal white
• • • •
1) The stand-by input is not available in changeover (C/O) mode or in heating controller applications as it is
assigned to the changeover input function. CR24-B3 should be used if the stand-by function is needed
in a changeover application.
2) The boost function is not available in changeover mode or in chilled ceiling applications with dew point
limiting. A combination of changeover and dew point limiting is possible.
3) The output can either be used as a common cooling and heating output in changeover mode or exclu-
sively as a cooling or heating output. The stand-by function is not available in changeover mode or in
heating controller applications.
4) The output can either be used as a common cooling and heating output in changeover mode or exclusi-
vely as a cooling or heating output.

Technical data sheet CR24-B1
www.belimo.com 5
Product information S4-CR24-.. • en • v2.2 • 01.2024 • Subject to changes
Technical data
Electrical data Nominal voltage AC 24 V 50/60 Hz
For wire sizing 3 VA, without actuators
Nominal voltage range AC 19.2...28.8 V
Connections Terminal block 1...3: 2.5 mm2
Terminal block 4...8: 1.5 mm2
Functional data Control characteristics P
– P-band heating / cooling Selectable: 1.5 / 1.0 K or 3.0 / 2.0 K
External temperature sensor (ai1) Type NTC, 5 k, sensing range 10...45°C
Heating setpoint Range 15...36°C (default 21°C)
– Energy hold off Heating 15°C / cooling 40°C
– Stand-by Heating –2 K / cooling +3 K
Dead band 1 K
Frost limit temperature 10°C
Operation (CR24-B.. only)
– Mode switch and status indication (LEDs) AUTO (green) – ECO (orange) – MAX (red)
– Rotary knob for setpoint adjustment ±3 K
 2x PP (for PC-Tool)
Inputs 2x analogue, 2x digital
– External temperature sensor (ai1) Type NTC, 5 k, sensing range 10...45°C
– External setpoint shift (ai2) 0...10 V corresponds to 0...10 K
– Digital inputs (di1, di2) Maximum current 10 mA
Outputs 1x analogue
– VAV system output (ao1) (0)2 ... 10 V, max. 5 mA
Norms und standards Protection class III Safety extra-low voltage
Degree of protection IP30 according to EN 60529
Mode of operation Type 1 according to EN 60730-1
Software class A according to EN 60730-1
EMC EU conformity CE marking
Ambient conditions
– Operation 0...50°C / 20...90% RH (without condensation)
– Transport and storage –25...70°C / 20...90% RH (without condensation)
Dimensions / Weight Dimensions (HxWxD) 99x84x32 mm
Weight 105 g
Housing colours
Baseplate
Cover
NCS 2005-R80B light grey
(corresponds approx. to RAL 7035)
RAL 9003 signal white
Temperature controller for single room
applications with one analogue output:
• The analogue output ao1 can be used in
VAV applications to contol one or more
VAV controllers.
• In changeover applications, the analogue
output ao1 can be changed over from coo-
ling to heating mode via an input.
Safety notes
!
• The controller must not be used outside the specified field of application,
especially in aircraft or in any other airborne means of transport.
• Only authorised specialists may carry out installation. All applicable legal or institutional installa-
tion regulations must be complied with during installation.
• The device may only be opened at the manufacturer's site. It does not contain any parts that can
be replaced or repaired by the user.
• The device contains electrical and electronic components and must not be disposed of as

Device variant
Type CR24-A1, same functionality as the
CR24-B1 but without operating elements.

Single room controller with one analogue output
CR24-B1
6www.belimo.com
Product information S4-CR24-.. • en • v2.2 • 01.2024 • Subject to changes
Electrical installation
Wiring diagram
1 2 6 7 8
• • •
0...10
V
AC 24 V
NTC
CR24-B1
ai/di1 di2 ai2
ao1 U51U52
T
~
T

Y [V]
tR[°C]
10
2
0
W
C
V
max
V
min
Y [V]
t
R
[°C]
W
H
10
2
0
W
C
V
max
V
min

DIP
Default
settings
1 P-band normal P-band wide
2 Input di2
Stand-by
Input di2
Changeover
1 2
Product features
Energy hold off
In energy saving mode, the room temperature is reduced to building protection level, i.e. either

instance in a room with an open window.
Stand-by The room temperature is reduced to stand-by level, i.e. either the heating setpoint is slightly
reduced or the cooling setpoint is slightly increased, for instance in a room that is temporarily
unoccupied.
Frost
The frost protection function is activated if the current room temperature falls below 10°C.
Changeover Changeover heating or heating/cooling.
External temperature sensor An external temperature sensor can be connected to the analogue input ai1, for instance in
order to measure the average room temperature in the exhaust air duct.
External setpoint shift An external 0...10 V signal at the analogue input ai2 can be used to shift the basic setpoint by
0...10 K, for instance for the summer/winter compensation.
These functions are described in detail on pages 17 to 24.
Inputs Output
3ai1 External temperature sensor 6 ao1 System output for Belimo VAV controller
di1 Energy hold off Other connections
4 di2 Stand-by / Changeover 7 PP1 Diagnostics socket 1
5 ai2 External setpoint shift 8 PP2 Diagnostics socket 2
Notes
• Connect via safety isolation transformer.
• Parallel connection of other actuators possible.
Note the performance data.
!
Key
Y [V] Output voltage in volt Vmax Maximum volumetric flow
tR[°C] Room temperature in degrees Celsius Vmin Minimum volumetric flow
WHHeating setpoint
WCCooling setpoint

Technical data sheet CR24-B2
www.belimo.com 7
Product information S4-CR24-.. • en • v2.2 • 01.2024 • Subject to changes
Technical data
Electrical data Nominal voltage AC 24 V 50/60 Hz
For wire sizing 3 VA, without actuators
Nominal voltage range AC 19.2...28.8 V
Connections Terminal block 1...3: 2.5 mm²
Terminal block 4...8: 1.5 mm²
Functional data Control characteristics P
– P-band heating / cooling Selectable: 1.5 / 1.0 K or 3.0 / 2.0 K
External temperature sensor (ai1) Type NTC, 5 k, sensing range 10...45°C
for example Belimo type TFK
Heating setpoint Range 15...36°C (default 21°C)
– Energy hold off Heating 15°C / cooling 40°C
– Stand-by Heating –2 K / cooling +3 K
Dead band 1 K
Frost limit temperature 10°C
Operation (CR24-B.. only)
– Mode switch and status indication (LEDs) AUTO (green) – ECO (orange) – MAX (red)
– Rotary knob for setpoint adjustment ±3 K
 2x PP (for PC-Tool)
Inputs 2x analogue, 3x digital
– External temperature sensor (ai1) Type NTC, 5 k, sensing range 10...45°C
– External setpoint shift (ai2) 0...10 V corresponds to 0...10 K
– Digital inputs (di1, di2, di3) Maximum current 10 mA
Outputs 2x analogue
– VAV system output (ao1) (0)2 ... 10 V, max. 5 mA
– Heating output (ao3) 3-point, AC 24 V, max. source current 0.5 A / 10 VA
(optimised for actuators with a running time of
approx. 150 s)
Norms und standards Protection class III Safety extra-low voltage
Degree of protection IP30 according to EN 60529
Mode of operation Type 1 according to EN 60730-1
Software class A according to EN 60730-1
EMC EU conformity CE marking
Ambient conditions
– Operation 0...50°C / 20...90% RH (without condensation)
– Transport and storage –25...70°C / 20...90% RH (without condensation)
Dimensions / Weight Dimensions (HxWxD) 99x84x32 mm
Weight 105 g
Housing colours
Baseplate
Cover
NCS 2005-R80B light grey
(corresponds approx. to RAL 7035)
RAL 9003 signal white
Temperature controller for single room
applications with two analog outputs:
• The analogue output ao1 can be used in
VAV applications to contol one or more
VAV controllers.
• The analogue heating output ao3 supplies
a 3-point signal.
Safety notes
!
• The controller must not be used outside the specified field of application,
especially in aircraft or in any other airborne means of transport.
• Only authorised specialists may carry out installation. All applicable legal or institutional installa-
tion regulations must be complied with during installation.
• The device may only be opened at the manufacturer's site. It does not contain any parts that can
be replaced or repaired by the user.
• The device contains electrical and electronic components and must not be disposed of as house-

Device variant
Type CR24-A1, same functionality as the
CR24-B1 but without operating elements.

Single room controller with two analogue outputs
CR24-B2
8www.belimo.com
Product information S4-CR24-.. • en • v2.2 • 01.2024 • Subject to changes

Y [V]
tR[°C]
W
H
10
2
8.4
0
W
C
V
max
V
min
V
maxH
ao3 ao1
Product features
Energy hold off
In energy saving mode, the room temperature is reduced to building protection level, i.e. either

instance in a room with an open window.
Stand-by The room temperature is reduced to stand-by level, i.e. either the heating setpoint is slightly
reduced or the cooling setpoint is slightly increased, for instance in a room that is temporarily
unoccupied.
Frost
The frost protection function is activated if the current room temperature falls below 10°C.
 The room can be ventilated with the maximum volumetric
purge conference rooms, hotel rooms etc.
External temperature sensor An external temperature sensor can be connected to the analogue input ai1, for instance in
order to measure the average room temperature in the exhaust air duct.
External setpoint shift An external DC 0...10 V signal at the analogue input ai2 can be used to shift the basic setpoint
by 0...10 K, for instance for the summer/winter compensation.
These functions are described in detail on pages 17 to 24.
Notes
• Connect via safety isolation transformer.
• Parallel connection of other actuators possible.
Note the performance data.
!
Electrical installation
Wiring diagram
1 2 9 10 6 7 8
3 4 12 5
0...10 V
NTC
CR24-B2
ai/di1 di2 di3 ai2
ao1ao3 U51U52
AC 24 V
T
~
T
Inputs Output
3ai1 External temperature sensor 6 ao1 System output for Belimo VAV controller
di1 Energy hold off 9/10 ao3 Heating (3-point)
4 di2 Stand-by Other connections
5 ai2 External setpoint shift 7 PP1 Diagnostics socket 1
12 di3 Air flush 8 PP2 Diagnostics socket 2

DIP
Default
settings
1 P-band normal P-band wide
2 Vmax heating off Vmax heating 80%
1 2
Key
Y [V] Output voltage in volt ao.. Analogue outputs
tR[°C] Room temperature in degrees Celsius Vmax Maximum volumetric flow
WHHeating setpoint VmaxHMaximum volumetric flow heating
WCCooling setpoint Vmin Minimum volumetric flow
Air flush

Technical data sheet CR24-B2E
www.belimo.com 9
Product information S4-CR24-.. • en • v2.2 • 01.2024 • Subject to changes
Technical data
Electrical data Nominal voltage AC 24 V 50/60 Hz
For wire sizing 3 VA, without actuators
Nominal voltage range AC 19.2...28.8 V
Connections Terminal block 1...3: 2.5 mm²
Terminal block 4...8: 1.5 mm²
Functional data Control characteristics P
– P-band heating / cooling 2 K with 2 resp. 3 stages / 2.0 K
External temperature sensor (ai1) Type NTC, 5 k, sensing range 10...45°C
for example Belimo type TFK
Heating setpoint Range 15...36°C (default 21°C)
– Energy hold off Heating 15°C / cooling 40°C
– Stand-by Heating –2 K / cooling +3 K
Dead band 1 K
Frost limit temperature 10°C
Operation (CR24-B.. only)
– Mode switch and status indication (LEDs) AUTO (green) – ECO (orange) – MAX (red)
– Rotary knob for setpoint adjustment ±3 K
 2x PP (for PC-Tool)
Inputs 2x analogue, 3x digital
– External temperature sensor (ai1) Type NTC, 5 k, sensing range 30...50°C
– External setpoint shift (ai2) 0...10 V corresponds to 0...10 K
– Digital inputs (di1, di2, di3) Maximum current 10 mA
Outputs 1x analogue, 2x digital
– VAV system output (ao1) (0)2 ... 10 V, max. 5 mA
– Heating output (do3), 2 stages Triac, AC 24 V, max. source current 0.5 A / 10 VA
Norms und standards Protection class III Safety extra-low voltage
Degree of protection IP30 according to EN 60529
Mode of operation Type 1 according to EN 60730-1
Software class A according to EN 60730-1
EMC EU conformity CE marking
Ambient conditions
– Operation 0...50°C / 20...90% RH (without condensation)
– Transport and storage –25...70°C / 20...90% RH (without condensation)
Dimensions / Weight Dimensions (HxWxD) 99x84x32 mm
Weight 105 g
Housing colours
Baseplate
Cover
NCS 2005-R80B light grey
(corresponds approx. to RAL 7035)
RAL 9003 signal white
Temperature controller for single room
applications with one analogue output and
two digital outputs:
• The analogueg output ao1 for cooling, e.g.
in VAV applications to contol one or more
VAV controllers.
• The digital heating output do3 for
– Electric air heater with one or two stages,
in binary mode with three stages
– open/close radiator valve
Safety notes
!
• The controller must not be used outside the specified field of application,
especially in aircraft or in any other airborne means of transport.
• Only authorised specialists may carry out installation. All applicable legal or institutional installa-
tion regulations must be complied with during installation.
• The device may only be opened at the manufacturer's site. It does not contain any parts that can
be replaced or repaired by the user.
• The device contains electrical and electronic components and must not be disposed of as house-

Device variant
Type CR24-A2E, same functionality as the
CR24-B2E but without operating elements.

Single room controller with one analogue output
and two digital outputs
CR24-B2E
10 www.belimo.com
Product information S4-CR24-.. • en • v2.2 • 01.2024 • Subject to changes
Product features
Energy hold off
In energy saving mode, the room temperature is reduced to building protection level, i.e. either

instance in a room with an open window.
Stand-by The room temperature is reduced to stand-by level, i.e. either the heating setpoint is slightly
reduced or the cooling setpoint is slightly increased, for instance in a room that is temporarily
unoccupied.
Frost
The frost protection function is activated if the current room temperature falls below 10°C.
Boost The room can be ventilated with the maximum volumetricmax) or heated up with the
maximum capacity.
Supply air temperature limiter An optionally mounted sensor allows to control the supply air temperature to a maximum of
50°C.
Vmax at heating 
Output mode The do3 output mode can be set accordingly to the application to
– stage for one-stage electric air heater or open/close radiator valve
– binary for two-stage electric air heater (stage I: ¹/, stage II: ²/) which will be ¹/, ²/, ³/
Soft start (roll-out feature) The built-in soft start and roll-out of the stage control provides temperature excess protection.
This helps to avoid service calls due to switched-off safety chains and reduces the electrical
load after a power-failure.
External setpoint shift An external DC 0...10 V signal at the analogue input ai2 can be used to shift the basic setpoint
by 0...10 K, for instance for the summer/winter compensation.
These functions are described in detail on pages 17 to 24.

10
0
2
Y [V]
W
C
W
H
ao1
t
R
[°C]
Boost
II
I
8,4
do3 V
max
V
min
V
maxH
Key
Y [V] Output voltage in volt ao1 Cooling output
tR[°C] Room temperature in degrees Celsius System output for Belimo VAV controller
WHHeating setpoint do3 Heating stage I
WCCooling setpoint Heating stage II
Output on/off Vmax Maximum volumetric flow
VmaxHMaximum volumetric flow heating
Vmin Minimum volumetric flow

DIP
Default
settings
1 1 or 2 stage Binary mode
2 Vmax heating off Vmax heating on
1 2

Single room controller with one analogue output
and two digital outputs CR24-B2E
www.belimo.com 11
Product information S4-CR24-.. • en • v2.2 • 01.2024 • Subject to changes
Electrical installation
Wiring diagram
13
y5
U5
2
~
VAV 2
a) b)
CR24-B2E
13
y
5
U5
12 7 8611109
ao1 U5 1U5 2
4123 5
di2 di3ai/di1 ai2
0...10V
NTC
2
~
VAV 1
I
II
°C°C
13
y
5
U5
12 7 8611109
2
~
VAV 1
ao1 U5 1U5 2
do3/1
do3/1 do3/2
AC 24 V
T
~
T
Note
• Connect via safety isolation transformer.
• Parallel connection of other actuators possible.
Note the performance data.
!
Inputs Output
3
ai1 Supply air temperature limiter 6 ao1 System output for Belimo VAV controller
di1 Energy hold off 9 do3/1 Heating stage I Open/close radiator
valve
4 di2 Stand-by 10 do3/2 Heating stage II
5 ai2 External setpoint shift Other connections
12 di3 Boost 7 PP1 Diagnostics socket 1
8 PP2 Diagnostics socket 2
(optional)
single- or multi-stage
Local safety
chain *
* Note:
Installation and safety circuit
according to local laws and
regulations!
Stage I Stage I II
Electric air heater
Electric air heater
a) Parallel control
b) Primary/secondary operation
Open/close valve

12 www.belimo.com
Product information S4-CR24-.. • en • v2.2 • 01.2024 • Subject to changes

Technical data sheet CR24-B3
www.belimo.com 13
Product information S4-CR24-.. • en • v2.2 • 01.2024 • Subject to changes
Technical data
Electrical data Nominal voltage AC 24 V 50/60 Hz
For wire sizing 3 VA, without actuators
Nominal voltage range AC 19.2...28.8 V
Connections Terminal block 1...3: 2.5 mm²
Terminal block 4...8: 1.5 mm²
Functional data Control characteristics P / PI
– P-band heating / cooling Selectable: 1.5 / 1.0 K or 3.0 / 2.0 K
External temperature sensor (ai1) Type NTC, 5 k, sensing range 10...45°C
for example Belimo type TFK
Heating setpoint Range 15...36°C (default 21°C)
– Energy hold off Heating 15°C / cooling 40°C
– Stand-by Heating –2 K / cooling +3 K
Dead band 1 K
Frost limit temperature 10°C
Operation (CR24-B.. only)
– Mode switch and status indication (LEDs) AUTO (green) – ECO (orange) – MAX (red)
– Rotary knob for setpoint adjustment ±3 K
 2x PP (for PC-Tool)
Inputs 2x analogue, 3x digital
– External temperature sensor (ai1) Type NTC, 5 k, sensing range 10...45°C
– External setpoint shift (ai2) 0...10 V corresponds to 0...10 K
– Digital inputs (di1, di2, di3) Maximum current 10 mA
Outputs 3x analogue
– VAV system output (ao1) (0)2 ... 10 V, max. 5 mA
– Heating / cooling output (ao2) 0...10 V, max. 5 mA
– Heating output (ao3) 3-point, AC 24 V, max. source current 0.5 A / 10 VA
(optimised for actuators with a running time of
approx. 150 s)
Norms und standards Protection class III Safety extra-low voltage
Degree of protection IP30 according to EN 60529
Mode of operation Type 1 according to EN 60730-1
Software class A according to EN 60730-1
EMC EU conformity CE marking
Ambient conditions
– Operation 0...50°C / 20...90% RH (without condensation)
– Transport and storage –25...70°C / 20...90% RH (without condensation)
Dimensions / Weight Dimensions (HxWxD) 99x84x32 mm
Weight 105 g
Housing colours
Baseplate
Cover
NCS 2005-R80B light grey
(corresponds approx. to RAL 7035)
RAL 9003 signal white
Temperature controller for single room
applications with three analogue outputs:
• The analogue output ao1 can be used in
VAV applications to contol one or more
VAV controllers.
• The analogue output ao2 can be used to

(changeover).
• The analogue heating output ao3 supplies a
3-point signal.
Safety notes
!
• The controller must not be used outside the specified field of application,
especially in aircraft or in any other airborne means of transport.
• Only authorised specialists may carry out installation. All applicable legal or institutional
installation regulations must be complied with during installation.
• The device may only be opened at the manufacturer's site. It does not contain any parts that can
be replaced or repaired by the user.
• The device contains electrical and electronic components and must not be disposed of as

Device variant
Type CR24-A3, same functionality as the
CR24-B3 but without operating elements.
Application chilled

eu.bac Control Accurancy
according to EN15500 =
CA 0.7
020718
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.

Single room controller with three analogue outputs
CR24-B3
14 www.belimo.com
Product information S4-CR24-.. • en • v2.2 • 01.2024 • Subject to changes
Product features
Energy hold off
In energy saving mode, the room temperature is reduced to building protection level, i.e. either

instance in a room with an open window.
Stand-by The room temperature is reduced to stand-by level, i.e. either the heating setpoint is slightly
reduced or the cooling setpoint is slightly increased, for instance in a room that is temporarily
unoccupied.
Frost
The frost protection function is activated if the current room temperature falls below 10°C.
Changeover Changeover heating or heating/cooling.
Chilled ceiling with dew point limiting
If the temperature falls below the dew point, the corresponding output is set to 0.
Boost The room can be ventilated with the maximum volumetricmax) or heated or cooled with
the maximum capacity.
External temperature sensor An external temperature sensor can be connected to the analog input ai1, for instance in order
to measure the average room temperature in the exhaust air duct.
External setpoint shift An external DC 0...10 V signal at the analogue input ai2 can be used to shift the basic setpoint
by 0...10 K, for instance for the summer/winter compensation.
These functions are described in detail on pages 17 to 24.
Electrical installation
Wiring diagram
1 2 9 10 11 6 7 8
3 4 12 5
NTC
CR24-B3
ai/di1 di2 di3 ai2
ao1ao2ao3 U5
1
U5
2
AC 24 V
T
~
0...10 V
T
Note
• Connect via safety isolation transformer.
• Parallel connection of other actuators possible.
Note the performance data.
!

Y [V]
t
R
[°C
]
10
2
8.4
0
Vmax
Vmin
VmaxH
ao3
ao1
ao1
Boost
ao2
WHWC

DIP
Default
settings
1 P-band normal P-band wide
2 Vmax heating off Vmax heating 80%
3 Output ao2
Heating
Output ao2
Changeover
Cooling
4 Input di3
Boost
Input di3
Changeover
Dew point
5 Boost
Temperatur
Boost
Vmax
6 Control characteristic
PI
Control characteristic
P
1 2 3 4 5 6
Key
Y [V] Output voltage in volt ao.. Analogue outputs
tR[°C] Room temperature in degrees Celsius Vmax Maximum volumetric flow
WHHeating setpoint VmaxHMaximum volumetric flow heating
WCCooling setpoint Vmin Minimum volumetric flow
Inputs Output
3ai1 External temperature sensor 6 ao1 System output for Belimo VAV controller
di1 Energy hold off 9/10 ao3 Heating (3-point)
4 di2 Stand-by 11 ao2 Heating / Cooling
5 ai2 External setpoint shift Other connections
12 di3 Boost / Changeover / Dew point 7 PP1 Diagnostics socket 1
8 PP2 Diagnostics socket 2

Operation CR24-..
www.belimo.com 15
Product information S4-CR24-.. • en • v2.2 • 01.2024 • Subject to changes
2 1
Mode switch and status indication
There are three possible operating modes:
• AUTO – optimum comfort mode
The room is heated, cooled or ventilated with the highest level of
comfort, providing this is permitted by the external control signals.

enabled.
• ECO – optimum energy mode
The room is heated, cooled or ventilated with the stand-by settings,
providing this is permitted by the external control signals. The hea-
ting setpoint is reduced in this mode (–2 K) and the cooling setpoint
is increased (3 K). The room can be changed from "optimum energy"

boost function are enabled. ECO mode is intended for rooms that
are only irregularly occupied or at reduced demand.
• MAX – boost function
The room is ventilated with the maximum volumetric air and heated
or cooled with the maximum capacity, providing this is permitted by
the external control signals.
The boost function will be deactiveded:
– timer elapsed
– setpoint reached (VAV fixed 15 minutes)
– change to another mode (AUTO or ECO)
Measuring point terminals
Measuring points for all terminals (also during operation)
Internal function test
A comprehensive internal function test, including a nominal voltage
test (AC 24 V), can be started for the controller with the mode switch.
The three LEDs (status indication) indicate the voltage level and the
states.

The connected actuators, and thus also the heating and cooling con-
-
ture with the rotary knob for adjusting the setpoint.
PC-Tool connection
Diagnostics sockets 1 and 2 are used for PP communication with the
connected Belimo MFT actuators or VAV controllers. As a result, phy-

Operator level 1 – Operation Operating mode / Setpoint CR24-B.. only
DIP switches for configuration
DIP switches 1 and 2 (CR24-B1, BR24-B2 and CR24-B2E) or 1 to 6
(CR24-B3)
Basic setpoint adjustment W(heating setpoint)
Potentiometer 15...36°C (default 21°C)
Label for settings
Used to record the selected settings (DIP switches and basic set-
point).
Operator level 2 – Configuration Application / Parameters all CR24-..
Operator level 3 – Service Test / Simulation all CR24-..
Rotary knob
for setpoint adjustment
Potentiometer ±3 K
Mode switch
• MAX
• ECO
• AUTO
Status indication
• MAX (red)
• ECO (orange)
• AUTO (green)
Or
d
er-Nr
.
Order- Nr.
CR24-B2xxxxx
W
H
U5/
2
U5/
1
123456
ON
OF F
21
36
15
Measuring
point terminals
PC-Tool connection
Internal function test
Basic setpoint adjustmentDIP switches for configuration
Label for settings
1
2
3
4
5
6
7
8
Rotary knob

9
10
11
12

16 www.belimo.com
Product information S4-CR24-.. • en • v2.2 • 01.2024 • Subject to changes

Functions CR24-..
www.belimo.com 17
Product information S4-CR24-.. • en • v2.2 • 01.2024 • Subject to changes
Introduction CR24-B.. only
The control functions define the behaviour of the controller outputs and influence the current
setpoint.
Both the level of comfort and the energy saving potential can be significantly enhanced by
installing suitable sensors on the input side.
Please refer to the table on page 4 for an overview of the functions of the three basic CR24-B..
types. These functions are described in detail below.
Operating status Heating setpoint Cooling setpoint
Comfort Basic setpoint WH
± 3 K setpoint adjustment
+ setpoint shift 0...10 V
Comfort heating setpoint WA
+ 1 K dead band
Stand-by Comfort heating setpoint WA
– 2 K stand-by offset heating
Comfort heating setpoint WA
+ 1 K dead band
+ 3 K stand-by offset cooling
Energy hold off Fixed 15°C (building protection) Fixed 40°C (building protection)
Frost Fixed 10°C Not relevant
Setpoint calculation
Examples Comfort Stand-by
Y
tR
10
2
0
Energy hold off
Stand-by
Basic setpoint WH
Cooling
Heating
±3 K Setpoint adjustment
Setpoint shift 0...10 V
Dead band
Frost
Comfort heating setpoint WA
VAV
Y
tR
+1 K dead band
23°C comfort heating setpoint WA
Y
tR
+1 K dead band
23°C comfort heating setpoint WA
+3 K Stand-by offset cooling
–2 K Stand-by offset heating

Functions
CR24-..
18 www.belimo.com
Product information S4-CR24-.. • en • v2.2 • 01.2024 • Subject to changes
Y [V]
t
R
[°C]
W
A
10
2
0
V
max
V
min
Y [V]
t
R
[°C
]
WA
10
8.4
2
0
ao1ao2ao3
ao1
Vmax
.
Vmin
.
If a local detector (e.g. a window switch) acts on the digital input di1
and closes the corresponding contact, the room is adjusted to the
building protection settings in energy saving mode. In other words, the
heating setpoint is significantly reduced (15°C) or the cooling setpoint
significantly increased (40°C), though not sufficiently to cause dama-
ge to sensitive objects (plants, paintings etc.).
Typical applications
– A window switch at di1 stops all energy consumption from the mo-
ment the window is opened until the lower or upper building protec-
tion limit is reached.
– Higher-level override command, e.g. building management system.
Notes
– The minimum VAV output is set to 0 V instead of 2 V while energy
hold off is active (forced closing in 2...10 V).
– The mode switch (operator level 1) is deactivated while energy hold
off is active (input di1 takes priority).
– If an external temperature sensor is used, the frost limit is monito-
red by the internal sensor while energy hold off is active.
– Due to the automatic sensor detection, the change to energy hold
off takes about 40 seconds.
If a local detector (e.g. a motion detector) acts on the digital input
di2 and closes the corresponding contact, the room is adjusted to the
stand-by settings. In other words, the heating setpoint is reduced by 2
K or the cooling setpoint is increased by 3 K.
Typical applications
– A motion detector, a light switch or another detector at di2 reduces
the energy consumption of unoccupied rooms.
– Higher-level override command, e.g. building management system.
Y [V]
tR[°C]
WA
10
2
0
Vmax
.
Vmin
.
1 2
4
di2
CR24-B..
AC 24 V
T
~
Stand-by
Stand-by
Energy hold off Digital input di1 all CR24-..
Stand-by Digital input di2 all CR24-..

heating, e.g. for:
– Providing or assisting heating with electric air heater.
 
VAV function: volumetric flow in heating mode (electric air heater) CR24-B2 und CR24-B3 only
CR24-B2 configuration
The VAV function is configured using DIP switch
2.
1 2
CR24-B3 configuration
The VAV function is configured using DIP switch
2.
61 2 43 5
Vmax heating
closed
1 2
3
ai/di1
NTC
CR24-B..
AC 24 V
T
~
Energy hold off
Energy hold off
Key
Y Output signal
tRRoom temperature
WACurrent setpoint
Key
Y Output signal
tRRoom temperature
WACurrent setpoint
Key
Y Output signal
tRRoom temperature
WACurrent setpoint

Functions CR24-..
www.belimo.com 19
Product information S4-CR24-.. • en • v2.2 • 01.2024 • Subject to changes

heating, e.g. for:
– Provision without assisting heating with air.
 
Electric air heater CR24-B2E only
1 2
3
ai/di1
NTC
CR24-B..
AC 24 V
T
~
An external NTC temperature sensor can be connected to the
analogue input ai1. Sensor type: NTC 5k (5 k)
Typical application
A temperature sensor measures the average room temperature in the
exhaust air duct.
Notes
– The controller automatically detects the presence of an
external sensor.
– It is possible to install an energy hold off switch simultaneously
at di1, in which case the system changeover to the internal sensor
(see also "Energy hold off"). This permits the room
temperature to be monitored in order to protect the building.
External
temperature sensor
External temperature sensor Analog input ai1 CR24-B1, CR24-B2, CR24-B3
[°C]
30
40
50
60
70
80
[°C]
30
40
50
60
70
80
An external NTC temperature sensor can be connected to the

Function: The temperature of the supply air is limited by shedding
individual load increments if the maximum temperature is exceeded.
This results in an almost modulating control characteristic.

Notes
– The controller automatically detects the presence of a supply air
temperature limitation sensor.
– Combined application with EHO switch:
EHO active = supply air temperature limitation not active
Supply air temperature limitation Analog input ai1 CR24-B2E only
1 2
34 5
AC 24 V
NTC
CR24-B2E
ai/di1 di2
12
di3 ai2
T
~
Time
Supply air
temperature
Mean value 45 ... 46°C
Supply air
temperature
Time
EHO
II
I
Y [V]
t
R
[°C]
10
8.4
2
0
do3
X
P
H
X
P
C
ao1
W
H
W
C
Vmax
Vmin
closed
Volumetric flow
VmaxH
Key
Y Output signal
tRRoom temperature
WHSetpoint Heating
WCSetpoint Cooling
XPHP-band Heating
XPCP-band Cooling
VmaxHVmax Heating
CR24-B2E configuration
This function is activated using DIP switch 2.
1 2
External
temperature sensor
Without supply air limitation With supply air limitation

Functions
CR24-..
20 www.belimo.com
Product information S4-CR24-.. • en • v2.2 • 01.2024 • Subject to changes
Y [V]
tR[°C]
WA
10
2
0
1 2
12
di3
CR24-B2
AC 24 V
T
~
1 2
5
0...10 V
ai2
CR24-B..
AC 24 V
T
~
T
An external 0...10 V signal at the analogue input ai2 can be used to
shift the basic setpoint by 0...10 K (corresponds to 0...10 V).
Typical application
– Summer/winter compensation
Setpoint shift
Air flush
Air flush
The CR24-B2 controller allows override control at the digital input di3
to enable the room to be flushed with the maximum volumetric flow
(Vmax).
Typical applications
– Purging conference rooms, hotel rooms etc.
(e.g. time switch-controlled)
– Assisting smoke extraction
 
Notes
– The VAV output ao1 is set to a fixed value of Vmax (10 V).
– The heating output ao3 remains in the normal control mode and

External setpoint shift Analog input ai2 all CR24-..
Air flush Digital input di3 CR24-B2 only
Notes
A negative shift can be achieved by adjusting the basic setpoint to the

case:
– 0... 5 V corresponds to 16...21°C and
– 5...10 V corresponds to 21...26°C (see diagram opposite)
Auto
Air flush
W [°C]
S [V]
5.00
26
21
16
10
Key
W Setpoint
S Shift signal
Key
Y Output signal
tRRoom temperature
WACurrent setpoint