Lutron Electronics LR-HVAC-230-S User manual

P/N 041475 Rev. A
1 Technical Support: +44.(0)20.7702.0657
LR-HVAC-230-S
Room Thermostat
LR-HVAC-230-S
Application and Set-Up Guide
LR-HVAC-230-S

Room Thermostat, LR-HVAC-230-S, Application and Set-Up Guide
2 Technical Support: +44.(0)20.7702.0657
Table of Contents
About this document ........................................................................................................................................4
Before you start............................................................................................................................................4
Document use / request to the reader ...........................................................................................................5
Summary ............................................................................................................................................................5
Applications..................................................................................................................................................5
Functions......................................................................................................................................................6
Integration via Modbus .................................................................................................................................6
Compatible Accessory Devices by Siemens .................................................................................................7
Functions............................................................................................................................................................9
Temperature control .....................................................................................................................................9
Operating modes........................................................................................................................................10
Different ways to influence the operating mode....................................................................................11
Room temperature setpoint........................................................................................................................12
Description...........................................................................................................................................12
Setting and adjusting setpoints ............................................................................................................13
Applications overview .................................................................................................................................14
Additional functions ....................................................................................................................................15
Control sequences .....................................................................................................................................18
Sequences overview (setting via parameter P01) .................................................................................18
2-pipe fan coil unit ...............................................................................................................................19
2-pipe fan coil unit with electric heater.................................................................................................20
4-pipe fan coil unit ...............................................................................................................................22
Chilled / heated ceiling and radiator applications...................................................................................23
Compressor applications .....................................................................................................................23
Setpoints and sequences.....................................................................................................................24
Control outputs ..........................................................................................................................................26
Overview..............................................................................................................................................26
Control outputs configuration (setting via DIP switches) .......................................................................27
Fan control .................................................................................................................................................28

Room Thermostat, LR-HVAC-230-S, Application and Set-Up Guide
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Table of Contents (continued)
Functions (continued)
Multifunctional input, digital input................................................................................................................31
Handling faults............................................................................................................................................32
Modbus RTU mode....................................................................................................................................32
Control parameters.....................................................................................................................................34
Parameter setting via local HMI............................................................................................................34
Parameters of the “Service level” .........................................................................................................35
Parameters of the “Expert level with diagnostics and test”...................................................................36
Handling ...........................................................................................................................................................39
Mounting and installation ............................................................................................................................39
Commissioning...........................................................................................................................................40
Operation ...................................................................................................................................................41
Connection.......................................................................................................................................................43
Connection terminals..................................................................................................................................43
Connection diagrams .................................................................................................................................44
Mechanical design ..........................................................................................................................................45
General.......................................................................................................................................................45
Dimensions ......................................................................................................................................................47
Technical data .................................................................................................................................................48

Room Thermostat, LR-HVAC-230-S, Application and Set-Up Guide
4 Technical Support: +44.(0)20.7702.0657
About This Document
Before you start
Document use /request to the reader
Before using our products, it is important that you read the documents supplied with or ordered at the same time as the
products (equipment, applications, tools, etc.) carefully and in full.
We assume that persons using our products and documents are authorized and trained appropriately and have the
technical knowledge required to use our products as intended.

Room Thermostat, LR-HVAC-230-S, Application and Set-Up Guide
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Summary
Applications
Fan coil units via ON / OFF outputs:
• 2-pipe system*
• 2-pipe system with electric heater
• 4-pipe system
Chilled / heated ceilings (or radiators) via ON / OFF outputs:
• Chilled / heated ceiling*
• Chilled / heated ceiling with electric heater
• Chilled / heated ceiling and radiator / floor heating
Compressors: via ON / OFF control
• 1-stage compressors in DX type equipment
• 1-stage compressors in DX type equipment with electric heater
The room thermostats are delivered with a fixed set of applications.
The relevant application is selected and activated during commissioning using the Local DIP switch and HMI
Features
• Operating modes: Comfort, Economy (Energy Saving) and Protection (Deep Energy Saving)
• ON / OFF or 3-position control outputs (relay)
• Output for 3-speed or 1-speed fan
• Automatic or manual heating / cooling changeover
• Backlit display
• 230 V~operating voltage
* Note: with both ON / OFF or 3-position modulating control output.
continued next page

Room Thermostat, LR-HVAC-230-S, Application and Set-Up Guide
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Summary (continued)
Functions
• Room temperature control via built-in temperature sensor or external room temperature / return air temperature sensor
• Changeover between heating and cooling mode (automatic via local sensor or manually)
• Selection of applications via DIP switches and HMI.
• Select operating mode via operating mode button on the thermostat
• 1- or 3-speed fan control (automatically or manually)
• Display of current room temperature or setpoint in °C and / or °F
• Minimum and maximum limitation of room temperature setpoint
• Button lock (automatically or manually)
• 2 multifunctional inputs, freely selectable for:
– Operating mode switchover contact (keycard, window contact, etc.)
– Sensor for automatic heating / cooling changeover
– External room temperature or return air temperature sensor
– Dew point sensor
– Electric heater enable
– Fault input
– Monitor input for temperature sensor or switch state
• Advanced fan control function, e.g. fan kick, fan start, selectable fan operation (enable, disable or depending on heating or
cooling mode)
• “Purge” function together with 2-port valve in a 2-pipe changeover system
• Reminder to clean fan filters
• Floor heating temperature limitation
• Reload factory settings for commissioning and control parameters
• RS 485 terminals MUX, _and COM for communication with LutronRcompatible devices
Integration via Modbus
The LR-HVAC-230-S is a communicating thermostat with Modbus open protocol on RTU (Remote Terminal Unit) mode
enabling easy integration into LutronRmyRoomTand HomeWorksRQS solutions.
The following functions are available:
• Central controls of room operating modes, setpoints, fan speed and fan mode
• Remote monitoring e.g. operating mode, control outputs, temperature sensor or switch, etc.
• Alarming, e.g. external fault contact, condensation, clean filter, etc.
Engineering and commissioning can be done using local DIP switches / HMI

Room Thermostat, LR-HVAC-230-S, Application and Set-Up Guide
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Summary (continued)
Compatible Accessory Devices by Siemens
Description Siemens product no. Siemens data sheet
Cable temperature sensor or changeover sensor,
cable length 2.5 m QAH11.1 1840
Room temperature sensor QAA32 1747
Cable temperature sensor (under floor heating),
cable length 4 m QAP1030 / UFH 1854
Condensation monitor QXA2601 / QXA2602 /
QXA2603 /AQX2604 3302
ON / OFF actuators:
Electromotoric ON / OFF actuator SFA21... 4863
Electromotoric ON / OFF valve and actuator
(only available in AP, UAE, SA and IN) MVI… / MXI… 4867
Zone valve actuator
(only available in AP, UAE, SA and IN) SUA… 4832
Thermal actuator
(for radiator valves) STA23... 4884
Thermal actuator
(for small valves 2.5 mm) STP23... 4884
3-position actuators:
Electrical actuator, 3-position
(for radiator valves) SSA31... 4893
Electrical actuator, 3-position
(for 2- and 3-port valves / V…P45) SSC31… 4895
Electrical actuator, 3-position
(for small valves 2.5 mm) SSP31… 4864
Electrical actuator, 3-position
(for small valves 5.5 mm) SSB31... 4891
Electrical actuator, 3-position
(for small valves 5.5 mm) SSD31... 4861
Electromotoric actuator, 3-position
(for small valves 5.5 mm) SQS35… 4573
continued next page

Room Thermostat, LR-HVAC-230-S, Application and Set-Up Guide
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Summary (continued)
Compatible Accessory Devices by Siemens (continued)
Description Siemens
product no. / SSN Siemens data sheet
Changeover mounting kit sensor, cable length
2.5 m (50 pcs / package) ARG86.3 N3009
Plastic mounting spacer for flush mount
thermostats to increase the headroom in the
conduit box by 10 mm
ARG70.3 N3009
Conduit box for flush mounted thermostat ARG71 / S55770-T137 N3009

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Continued on next page
Functions
Temperature control
General note: Parameters
Setting of the control parameters (P01, etc., mentioned throughout the document) is described on page 34.
Temperature control
The thermostat acquires the room temperature via built-in sensor, external room temperature sensor, or external return
air temperature sensor, and maintains the setpoint by delivering actuator control commands to heating and / or cooling
equipment. The following control outputs are available:
• ON / OFF control (2-position)
• Modulating PI / P control with 3-position control output (only for 2-pipe applications)
The switching differential or proportional band is 2 K for heating mode and 1 K for cooling mode (adjustable via parameters
P30 and P31).
The integral action time for modulating PI (Proportional and Integral) control is 5 minutes (adjustable via parameter P35).
Display
The display shows the acquired room temperature or the Comfort setpoint, selectable via parameter P06. The factory
setting displays the current room temperature.
Use parameter P04 to display the room temperature or setpoint in °F rather than °C as needed.
Heating and Cooling /
The acquired room temperature (internal or external sensor) is also available as information in the LutronRsystem.
• With automatic changeover or continuous heating / cooling, symbols / indicate that the system currently heats or cools
(heating or cooling output is activated).
• With manual changeover (P01 = 2), symbols / indicate that the system currently operates in heating or cooling mode.
Thus, the symbols are displayed even when the thermostat operates in the neutral zone.
Concurrent display of °C and °F
Concurrent display of the current temperature or setpoint in °C and °F (parameter P07 = 1) is possible on the thermostat.

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Functions (continued)
Operating modes
The thermostat’s operating mode can be influenced in different ways. e.g. operating mode button, switch over contact,
etc. Specific heating and cooling setpoints are assigned to each operating mode.
The following operating modes are available:
• Comfort :
In Comfort mode, the thermostat maintains the Comfort setpoint. This setpoint can be defined via parameters P7, P8
and P9.
Also, it can be locally adjusted via the + / - buttons or remotely via system programming.
In Comfort mode, the fan can be set to automatic or manual fan speed: Low, medium or high.
• Economy :
A preset setpoint in Economy mode can be defined via parameters P11 and P12. The thermostat switches to Economy
mode when:
– The operating mode button is pressed (only possible if parameter P02 is set to 2)
– Economy mode is selected via system programming.
– An operating mode switchover contact (e.g. keycard contact presence detector, window contact) is active.
The contact can be connected to multifunctional input X1, X2.
Set parameter P38 / P40 to 3 (P02 is irrelevant) *
• Protection :
In Protection mode, the system is:
– Protected against frost (factory setting 8 °C, can be disabled or changed via P65)
– Protected against overheating (factory setting OFF, can be enabled or changed via P66)
No other operating mode can be selected locally if Protection mode is commanded via the system programming.
is displayed.
* Operating mode switchover: Only one input source must be used, either local input X1 / X2 or the system programming.
User operations are ineffective and “OFF” is displayed if the operating mode switchover contact is active.

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Functions (continued)
Different ways to influence the operating mode
Priority of operating mode interventions
The operating mode can be influenced by different interventions. The table below shows the priorities of different
interventions. (i.e. lower number = higher priority)
Priority Description Remark
Commissioning In parameter setting mode (highest priority), you can always command an operating
mode independent of all other settings or intervention via the system programming and
local input.
Operating mode
switchover contact
If the contact is closed, the operating mode changes to Economy. This overrides the
operating mode on the thermostat.
Operating mode via
system programming
The operating mode can be changed via system programming.
Note: Operating mode button is disabled if Protection mode is commanded via system
programming.
Operating mode button The user can switch the operating mode via the operating mode button.
Note: Higher priority commands can override the lower priority command. If operating mode is set via system
programming, the unit will indicate by flashing “OFF” when Operating Mode button pressed by user.
Availability of Economy mode
The operating mode can be selected locally via the operating mode button.
The behavior of the operating mode button (user profile) can be defined via parameter P02, factory setting is
P02 = 1.
PO2 Description Remark
1• Switching manually between 2 modes, Economy is not available (factory setting).
• Suited for hotel guest rooms or commercial buildings.
2• Switching manually between 3 modes.
• Suited for homes and rooms where manual switching to Economy mode is desired.
Operating mode switchover contact (window contact)
The thermostat can be forced into Economy mode (e.g. when a window is opened, when a presence detector
signals “no one present”, when the keycard of a hotel room is withdrawn, etc.). The contact can be connected to
multifunctional input X1, X2. Set parameter P38, P40 to 3.
Note: Only one input source must be used, either local input X1 / X2 or system programming.
User operations are ineffective and “OFF” is displayed if the operating mode switch-over contact is active.

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Functions (continued)
Room temperature setpoint
Description
Comfort mode
The default setting for the Comfort basic setpoint is 21 °C and can be changed via parameter P08 or system programming.
The last intervention/input that was used will determine the setting.
The Comfort setpoint can be adjusted via the + / – buttons, or via the system programming.
The last intervention/input that was used will determine the setting.
Temporary setpoint
If the “Temporary setpoint” function is enabled via parameter P69, the Comfort setpoint is set back to the default Comfort
setpoint stored in P08 when the operating mode changes.
Setpoint limitation
For energy saving purposes, the setpoint setting range can be limited to minimum (P09) and maximum (P10) temperatures.
P09 < P10:
• If the minimum limit P09 is set lower than the maximum limit P10, both heating and cooling are adjustable between these
2 limits.
P09 ≥ P10:
• For heating or cooling applications (e.g. 2-stage):
– The setting range in cooling mode is from P09…P10
– The setting range in heating mode is from P09…P10 °C
• For heating and cooling applications (e.g. 4-pipe):
– The cooling and heating setpoints are adjustable
– The setting range in cooling mode is from P09…40 °C in place of 5…40 °C
– The setting range in heating mode is from 5…P10 °C in place of 5…40 °C
Examples 2-pipe heating OR cooling | 4-pipe heating AND cooling
P09 < P10
Cooling setpoint adjustable 18…25 °C
Heating setpoint adjustable 18…25 °C
P09 ≥ P10
P10 P09
25
o
C
21
o
C
5
o
C40
o
C
Cooling setpoint adjustable 25…40 °C
Heating setpoint adjustable 5…21 °C
Economy mode
Use control parameters P11 and P12 to adjust the Economy mode setpoints.
The heating setpoint is factory-set to 15 °C, and the cooling setpoint to 30 °C.
Continued on next page
P09 P10
25 oC
18 oC
5 oC40 oC

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Functions (continued)
Room temperature setpoint (continued)
Description (continued)
Protection mode
Use control parameters P65 and P66 to adjust the Protection mode setpoints.
The heating setpoint is factory-set to 8 °C (frost protection) and to OFF for cooling.
Notice: If a setpoint (Economy or Protection) is set to OFF, the thermostat does not control the room temperature in the
corresponding mode (heating or cooling).
This means no protective heating or cooling function and thus risk of frost in heating mode or risk of over-temperature
in cooling mode!
The Economy setpoints are accessible at the service level (P11, P12); the Protection setpoints at the expert level (P65, P66).
Setting and adjusting setpoints
General notes:
• Setting the Comfort basic setpoint will reset the runtime Comfort setpoint to the basic setpoint.
Notes on setpoint adjustment
• The resulting (current) setpoint heating and cooling is limited by the Protection setpoint; if Protection setpoint is OFF, then
minimum 5 °C and maximum 40 °C are used.
• The resulting setpoints for cooling and heating of the same operating mode have a minimum distance of 0.5 K between
them.
Continued on next page

Room Thermostat, LR-HVAC-230-S, Application and Set-Up Guide
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Functions (continued)
Applications overview
The thermostat supports the following applications, which can be configured using the DIP switches
inside the front panel of the unit.
If all DIP switches are set to OFF display will show “None” The DIP switches must be used to select an
application.
The LR-HVAC-230-S offers the applications printed in bold text (basic applications).
For universal applications (chilled ceiling, etc.), refer to section Chilled / heated ceiling and radiator
applications.
For compressor applications, refer to section Compressor applications.
Application and output signal DIP
switches
Diagram
Remote configuration
Not available (factory setting)
Display shows “None”
1
ON
23
Heating or cooling
• 2-pipe fan coil unit ON / OFF
(heating or cooling)
• Chilled / heated ceiling ON / OFF
(heating or cooling)
• 1-stage compressor ON / OFF
(heating or cooling)
1
ON
23
• 2-pipe fan coil unit 3-position
(heating or cooling)
• Chilled / heated ceiling 3-position
(heating or cooling)
Heating or cooling with electric heater
• 2-pipe fan coil unit with electric heater
(heating or cooling) ON / OFF
• Chilled / heated ceiling with electric
heater
(heating or cooling) ON / OFF
• 1-stage compressor with electric heater
(heating or cooling) ON / OFF
Heating or cooling
• 4-pipe fan coil unit ON / OFF
(heating or cooling)
• Chilled / heated ceiling ON / OFF
(heating or cooling)
• 1-stage compressor ON / OFF
(heating or cooling)
1 Only required for heating AND cooling applications (see section: Setpoints and sequences)
1
ON
23
1
ON
23
1
ON
23
Key
Y1 Heating or heating / cooling
valve actuator
Y2 Cooling valve actuator
YE Electric heater
M1 3–or 1-speed fan
B1 Return air temperature
sensor or external room
temperature sensor
(optional)
B2 Changeover sensor
(optional)
3076D20
(B1)
M1
Y1
T
B2
T
T
(B1)
Y1
M1
3171D21
T
B2
YE
T
(B1)
T
(B1)
T
Y2
Y1
M1
3076D22
(B1)
T
(B1)

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Functions (continued)
Additional functions
Automatic heating / cooling changeover via changeover sensor
If an external temperature sensor is connected to X1 / X2, and parameter P38 / P40 is =2, the water temperature acquired
by the changeover sensor is used to change over from heating to cooling mode, or vice versa.
• When the water temperature is above 28 °C (adjustable via parameter P37), the thermostat changes over to heating
mode.
It stays in heating mode until the temperature falls below 16 °C (adjustable via parameter P36).
• When the water temperature is below 16 °C (P36), the thermostat changes over to cooling mode.
It stays in cooling mode until the temperature rises above 28 °C (P37).
• If the water temperature is between the 2 changeover points immediately after power-up (inside the hysteresis), the
thermostat starts in previous mode.
The water temperature is acquired at 30-second intervals and the operating state is updated accordingly.
M Operating mode Cooling mode
Tw Water temperature Heating mode
Changeover switch
The temperature sensor for automatic heating / cooling changeover can be replaced by an external switch for manual,
remote changeover:
Contact open
heating mode
Contact closed
cooling mode
The sensor or switch can be connected to input terminal X2 or X1, depending on the commissioning of the inputs (P38,
P40).
See also section: Multifunctional input, digital input.
Manual heating / cooling changeover
• Manual heating / cooling changeover means selection via changeover button on the thermostat by repeatedly pushing
the button until the required mode is shown on the display (automatic changeover is done via an external sensor / switch
connected to X1, X2, or D1).
• If manual heating / cooling changeover is commissioned (P01 = 2), then heating / cooling mode cannot be changed via
changeover sensor / switch; it will remain in the last mode as selected locally via button.
External / return air temperature sensor
The thermostat acquires the room temperature via built-in sensor, external room temperature sensor, or external return air
temperature sensor connected to multifunctional input X1 or X2.
Inputs X1 or X2 must be commissioned accordingly. See section: Multifunctional input, digital input.
T ºC
(ºC)
Continued on next page

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Functions (continued)
Additional functions (continued)
Purge function
The changeover sensor ensures changeover from heating to cooling mode based on the acquired water temperature. We
recommend activating the “Purge” function (parameter P50) with 2-port valves. This function ensures correct acquisition of
the medium temperature even if the 2-port valve is closed for an extended period of time. The valve is then opened for 1 to
5 minutes (adjustable) at 2-hour intervals during off hours.
Notice: The “Purge” function (parameter P50) must be disabled if the thermostat is used in compressor-based
applications.
Avoid damage from moisture
In very warm and humid climates, the fan can be run periodically or continuously at a low fan speed (e.g. in empty
apartments or shops) in Economy mode by setting parameter P61, in order to avoid damage from moisture due to lack of
air circulation. See also section: Fan control, under Fan kick function.
Minimum output ON-time / OFF-time
Limit the ON / OFF switching cycle to protect the HVAC equipment, e.g. compressor and reduce wear and tear. The
minimum output on-time and off-time for 2-position control output can be adjusted from 1 to 20 minutes via parameters
P48 and P49.
The factory setting is 1 minute.
Readjusting the setpoint or heating / cooling mode changeover immediately results in calculation of the output state; the
outputs may not hold the minimum 1-minute ON / OFF time.
If parameter P48 or P49 is set to above 1 minute, the minimum ON / OFF time for the control output is maintained as set,
even if the setpoint or changeover mode is readjusted.
Floor heating / Floor cooling
All heating sequences can also be used for floor heating.
You can use fan coil unit heating / cooling sequences for floor heating or cooling by disabling the fan via parameter P52.
Floor temperature limitation function
The floor temperature should be limited for 2 reasons: Comfort and protection of the floor.
The floor temperature sensor, connected to multifunctional input X1 or X2, acquires the floor temperature. If the
temperature exceeds the parameterized limit (parame¬ter P51), the heating valve is fully closed until the floor temperature
drops to a level 2 K below the parameterized limit.
This function is factory-set to OFF (disabled).
Input X1 or X2 must be commissioned accordingly (P38 or P40 = 1).
See section: Multifunctional input, digital input.
Recommended values for P51:
• Living rooms:
Up to 26 °C for long-time presence, up to 28 °C for short-time presence.
• Bathrooms:
Up to 28 °C for long-time presence, up to 30 °C for short-time presence.

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Functions (continued)
Additional functions (continued)
The table below shows the relation between parameter, temperature source and temperature display:
Parameter P51 External temperature
sensor available
Source for display of
room temperature Output control based on Floor temperature limit function
OFF No Built-in sensor Built-in sensor Not active
OFF Yes External temperature
sensor
External temperature
sensor
Not active
10...50 ˚C No Built-in sensor Built-in sensor Not active
10…50 ˚C Yes Built-in sensor Built-in sensor + limit
by external sensor
Active
The “Floor temperature limitation” function influences the outputs listed in the table below:
“Floor temperature limit” function has
impact on:
Application Output Y11 Output Y21 Heating (P01 = 0 / 2 / 3) Cooling (P01 = 1 / 2 / 3
Heating and
cooling
(P01 = 4) Remark
2-pipe H / C valve Y11 N / A
2-pipe and
electric heater
H / C valve Electric heater Y21 Y21 * Only electric
heater
4-pipe Heating valve Cooling valve Y11 N / A Y11
* If P13 = ON Jelectric heater in cooling mode
Note: Either floor temperature sensor or external room temperature sensor can be used.
Dew point monitoring
Dew point monitoring is essential to prevent condensation on the chilled ceiling (cooling with fan disabled, parameter P52).
It helps avoid associated damage to the building.
A dew point sensor with a potential-free contact is connected to multifunctional input X1 or X2. If there is condensation, the
cooling valve is fully closed until no more condensation is detected, and the cooling output is disabled temporarily.
Fault state / Fault information
The condensation symbol “ ” is displayed during temporary override. The input must be commissioned accordingly (P38,
P40). See section: Multifunctional input, digital input.
Button lock
Manual “button lock” function is enabled by parameter P14 (0=Disabled, 1=Auto lock, 2=Manual lock).
When P14=2, press operating mode button for 5 seconds to lock or unlock all the buttons. If “Auto lock” is configured
(P14=1), the thermostat will automatically lock all the buttons 10 seconds after the last adjustment and the way to unlock
the buttons is the same as per manual lock.

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Functions (continued)
Control sequences
Sequences overview (setting via parameter P01)
The main control sequence (i.e. the water coil sequence of the fan coil unit) can be set via parameter P01.
The following sequences can be activated in the thermostats (each without or with auxiliary heating).
The available sequences depend on the application (selected via DIP switch, see section: Applications overview).
Parameter P01 = 0 P01 = 1 P01 = 2 P01 = 3 P01 = 4
Sequence
Available
for basic
application1 
Heating Cooling
= heating
sequence for
electric heater
Manually select
heating or cooling
sequence (using
the button on the
thermostat)
Automatic
heating / cooling
changeover via
external water
temperature sensor
or remote switch
Heating
and cooling
sequence, i.e.
4-pipe
2-pipe,
2-pipe and
electricheater
33 3 3
4-pipe 32323
1For chilled / heated ceiling and radiator applications, see section: Chilled / heated ceiling and radiator applications;
for compressor applications, see section: Compressor applications
2For manual and automatic changeover with 4-pipe applications, see section: 4-pipe fan coil unit:
– 4-pipe manual changeover (P01 = 2) means activating either cooling or heating outputs
– 4-pipe automatic changeover (P01 = 3) means swapping the control outputs according to a heating/ cooling sensor
or remote switch ("main and secondary" application), see section: 4-pipe fan coil unit
For the relation between setpoints and sequences, see section: Setpoints and sequences.
Continued on next page

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Functions (continued)
Control sequences (continued)
2-pipe fan coil unit
On 2-pipe applications, the thermostat controls a valve in heating / cooling mode with changeover (automatically or
manually), heating only, or cooling only. Cooling only is factory-set (P01 = 1).
ON / OFF control
Control sequence ON / OFF output
The diagrams below show the control sequence for 2-position control.
Heating mode Cooling mode
T (°C) Room temperature SDH Switching differential “Heating” (P30)
w Room temperature setpoint SDC Switching differential “Cooling” (P31)
YHC Control command “Valve” or “Compressor”
Modulating control: 3-position
Control sequence modulating output
The diagrams below show the control sequence for modulating PI control.
Heating mode Cooling mode
T (°C) Room temperature XpH Proportional band “Heating” (P30)
w Room temperature setpoint XpC Proportional band “Cooling” (P31)
YHC Control command “Valve”
Note: The diagrams only show the PI thermostat’s proportional part.
Setting the sequence and the control outputs
Refer to sections: Applications, Sequences overview, and Control outputs.
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Room Thermostat, LR-HVAC-230-S, Application and Set-Up Guide
20 Technical Support: +44.(0)20.7702.0657
Functions (continued)
Control sequences (continued)
2-pipe fan coil unit with electric heater
Heating or cooling with auxiliary heater
On 2-pipe applications with electric heater, the thermostat controls a valve in heating / cooling mode with changeover,
heating only, or cooling only plus an electric heater.
Cooling only is factory-set (P01 = 1) with enabled electric heater (P13).
Electric heating, active in cooling mode
In cooling mode, the valve receives an OPEN command if the acquired temperature is above the setpoint.
The electric heater receives an ON command if the acquired room temperature drops below “setpoint” minus “dead zone”
(= setpoint for electric heater) while the electric heater is enabled (parameter P13 = ON).
Note: “Setpoint for electric heater” is limited by parameter “Maximum setpoint for Comfort mode” (P10).
Electric heating in heating mode
In heating mode, the valve receives an OPEN command if the acquired temperature is below the setpoint. The electric
heater is used as an additional heating source when the heating energy controlled by the valve is insufficient.
The electric heater receives an ON command, if the temperature is below “setpoint” minus “setpoint differential” (= setpoint
for electric heater).
Electric heating and manual changeover
The electric heater is active in heating mode only and the control output for the valve is permanently disabled when manual
changeover is selected (P01 = 2).
Digital input “Enable electric heater”
Remote enabling / disabling of the electric heater is possible via input X1 or X2 for tariff regulations, energy savings, etc.
Input X1 or X2 must be commissioned accordingly (parameters P38, P40). See section 3.9 “Multifunctional input”.
Notice: An electric heater must always be protected by a safety limit thermostat!
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