Product Details | SAUTER
 

LET4***

How energy efficiency is improved
Protected, intelligent solution for optimal energy use.

Areas of application
As a bi-directional receiving station for the signals from the analogue LRT410 room thermostats and the digital LRA420 and LRA450 room operating units, the LET4*** is used as a single-room controller for every channel and for activating thermal actuators in underfloor heating control systems. The individual controllers communicate using a bi-directional signal. The pulses of the radio thermostats can be individually assigned to the corresponding channels.

Properties

  • Intelligent bi-directional wireless controllers for heating/cooling
  • Reception frequency: 868.3 MHz
  • Versions with or without LAN connection
  • LEDs for the functions, communication and operating modes
  • One LED per channel for visualisation and confirmation of the channel assignment
  • Emergency function when there is no signal reception
  • Individual configuration for every channel accessible from the outside
  • Integrated pump logic and potential-free output contact
  • With heating/cooling input and potential-free and configurable output
  • Input for monitoring the supply temperature
  • Input for monitoring the relative humidity

Technical description
  • Black housing (RAL9005) with transparent cover
  • Versions with 4, 8 and 12 channels
  • Including a transformer for the 24 V version
  • Monitoring of the inputs and state of the controller with LEDs
  • 24 V version with triac outputs for thermal actuators
  • 230 V version with relay outputs for thermal actuators
  • Automatic connection terminal, depending on the channel, 1 or 2 actuators/channel
  • Maximum number of thermal actuators with 12-channel version: 16
  • SD card for software update accessible from the outside
 
 
 

Product search

  • Product range
    • Cancel selection
    • ON/OFF controllers
    • Sensors and transducers
    • Stand-alone controller
    • Electric drives, control valves, butterfly valves
    • Pneumatics
    • Pneumatic drives, valves
    • Building Management System
  • Product family
    • Cancel selection
    • Thermostats
    • Frost monitors
    • Pressure switches
    • Humidistats
  • Product group
    • Cancel selection
    • Room thermostat
    • Fan-coil room-temperature controller, electromechanical
    • Fan-coil room-temperature controller, heating/cooling sequence
    • Fan-coil room-temperature controller, with digital display
    • Universal thermostat
  • Product group
    • Cancel selection
    • Continuous frost monitor with capillary sensor
    • Frost monitor/limiter with capillary sensor
  • Product group
    • Cancel selection
    • Heavy-duty pressure switch
    • Pressure switch
    • Pressure monitors and pressure switches
    • Specially designed pressure limiter
    • Differential pressure switch
  • Product group
    • Cancel selection
    • Room humidistat
    • Panel-mounted humidistat (packing unit: 50 pieces)
    • Duct-mounted humidistat
  • Product family
    • Cancel selection
    • Temperature
    • Flow, VAV
    • Pressure, differential pressure
    • Humidity
    • Air quality, AIQ, Other values
    • Thermowells
  • Product group
    • Cancel selection
    • Cable temperature sensor
    • Duct temperature sensor
    • Outdoor temperature sensor
    • Clamp-on temperature sensor
    • Room-temperature sensor, surface-mounted
    • Room temperature sensor, recessed
  • Product group
    • Cancel selection
    • Fine-differential-pressure transducer
    • Air-flow transducer
    • Differential pressure transducer
    • Flow probe for ventilation ducts
  • Product group
    • Cancel selection
    • Differential pressure transmitter
    • Pressure transmitter
  • Product group
    • Cancel selection
    • Dew point monitor and transducer
    • Duct transducer, enthalpy
    • Duct transducer, relative humidity and temperature
    • Room transducer, relative humidity and temperature
    •  Room transducer, relative humidity and temperature, recessed
  • Product group
    • Cancel selection
    • Sash sensor
    • Duct transducer, air quality (VOC)
    • Room transducer, air quality, surface-mounted
    • Duct transducer, CO2 and temperature
    • Room transducer, CO2, surface-mounted
    • Room transducer, CO2, recessed
  • Product group
    • Cancel selection
    • Thermowells
  • Product family
    • Cancel selection
    • equiflex and VAV
    • equitherm heating controllers
    • Intelligent unitary control for underfloor heating
    • flexotron controllers for ventilation and a/c
  • Product group
    • Cancel selection
    • Electronic air-conditioning controller, heating/cooling, equiflex
    • VAV controller, constant
    • Room-pressure controller
    • Fume-cupboard indicator and monitor
  • Product group
    • Cancel selection
    • Heating controller with digital user interface, equitherm
    • Heating controller for boiler control systems, equitherm
    • Heating controller for local and district heating, equitherm
    • Heating controller with two control loops for local or district heating, equitherm
    • Remote control unit
  • Product group
    • Cancel selection
    • Bi-directional wireless controller 868 MHz
    • Electronic room operating unit, 868 MHz
    • Electronic room thermostat with radio transmission
    • Electric distributor for control signals
    • Electronic room thermostat for heating and heating/cooling
    • Electronic room thermostat for heating and heating/cooling with display
  • Product group
    • Cancel selection
    • Electronic controller for simple applications, flexotron400
    • Communicative controller for universal use, flexotron800
    • Setpoint potentiometer
    • Active potentiometer
    • Switching unit
    • Electronic power control unit
    • Universal Contr. flexotron800 V2
  • Product family
    • Cancel selection
    • Electric drives
    • VAV compact controllers
    • Butterfly valvesmixing valves
    • Unit valves and drives
    • Regulating valves combined with drive
    • Valveco - Regulating Valve
    • 6-way ball valves
  • Product group
    • Cancel selection
    • Damper actuator
    • Damper actuator with SAUTER Universal Technology (SUT)
    • Damper actuator
    • Damper actuator with spring return
    • Damper actuator with spring return and positioner
    • Damper actuator with spring return
    • Damper actuator with spring return and positioner
    • Damper actuator
    • Damper actuator with SAUTER Universal Technology (SUT)
    • High-speed damper actuator with SAUTER Universal Technology (SUT)
    • Rotary actuator
    • Rotary actuator with positioner
    • Motorised actuator
    • Motorised actuator with positioner
    • Valve actuator
    • Valve actuator with SAUTER Universal Technology (SUT)
    • Rotary actuator for ball valve
    • Rotary actuator with SAUTER Universal Technology (SUT) for ball valve
    • Valve actuator with spring return
    • SUT valve actuator with spring return
    • High-speed rotary actuator with SAUTER Universal Technology (SUT) for ball valve
    • Rotary actuator with spring return for control ball valves
    • Rotary actuator with spring return and positioner
    • Valve actuator
    • Valve actuator
    • SUT valve actuator with positioner
    • SUT valve actuator with spring return
    • SUT valve actuator with safety function
    • Retrofit actuator
    • Retrofit actuator
    • Valve actuator
    • Valve actuator with SAUTER Universal Technology (SUT)
  • Product group
    • Cancel selection
    • VAV compact controller for laboratory and pharmaceutical applications (BACnet MSTP)
    • Standard VAV compact controller
    • BACnet MSTP standard VAV compact controller
    • VAV compact controller for laboratory and pharmaceutical applications
    • VAV compact controller
  • Product group
    • Cancel selection
    • Tight-sealing butterfly valve, PN 16
    • Control valve with flange connection, PN 6
    • Control valve with threaded connection, PN 10
  • Product group
    • Cancel selection
    • 3-way unit valve, PN 16
    • 2-way valve, PN16
    • 3-way unit valve, PN 16
    • Motorised actuator for unit valves
    • Motorised actuator for unit valves with positioner
    • Thermal actuator for unit valves with stroke indicator
    • Continuous actuator for unit valves, with stroke indicator
    • 2-way valve, PN 16
  • Product group
    • Cancel selection
    • 2-way regulating ball valve with female thread, PN 40
    • 3-way regulating ball valve with female thread, PN 40
    • 2-way valve with male thread, PN 16
    • 3-way valve with male thread, PN 16
    • 2-way flanged valve, PN 6 (el.)
    • 3-way flanged valve, PN 6 (el.)
    • 2-way flanged valve, PN 16/10 (el.)
    • 3-way flanged valve, PN 16/10 (el.)
    • 2-way flanged valve, PN 25/16 (el.)
    • 3-way flanged valve, PN 25/16 (el.)
    • Pressure-relieved 2-way flanged valve, PN 25 (el.)
    • 2-way flanged valve, PN 40 (el.)
    • 3-way flanged valve, PN 40 (el.)
    • 2-way valve with female thread, PN 16 (el.)
    • 3-way valve with female thread, PN 16 (el.)
    • 2-way flanged valve, PN 6
    • 3-way flanged valve, PN 6
    • 2-way flanged valve, PN 16
    • 3-way flanged valve, PN 16
    • 3-way change-over ball valve (L) with female thread, PN 40
    • 3-way change-over ball valve (T) with female thread, PN 40
    • 2-way cut-off ball valve with female thread, PN 40
    • 2-way regulating ball valve with male thread, PN 40
    • 3-way regulating ball valve with male thread, PN 40
    • 3-way change-over ball valve (T) with male thread, PN 40
    • 2-way cut-off ball valve with male thread, PN 40
  • Product group
    • Cancel selection
    • 2-way regulating valve for dynamic hydronic balancing, PN 16, Valveco
    • 2-way regulating valve for dynamic hydronic balancing, PN 16, Valveco
    • 2-way regulating valve for dynamic hydronic balancing, PN 25, Valveco compact
  • Product group
    • Cancel selection
    • 6-way ball valve with male thread, PN 16
  • Product family
    • Cancel selection
    • Installationof pneumatic systems
    • Relays and magnetic valves
    • Individual-room controlsystems, VAV
    • centair controller system
    • Accessories
  • Product group
    • Cancel selection
    • Instructions for pneumatic plants
  • Product group
    • Cancel selection
    • Averaging relay
    • Electropneumatic relay
  • Product group
    • Cancel selection
    • Pneumatic room-temperature controller
    • Pneum. duct-temperature controller
    • Pneumatic volume-flow controller
    • Pneumatic volume-flow controller
    • Pneumatic room-pressure controllers
    • Pneumatic air-volume transducer
    • Dual-channel air-volume controller
    • Air-volume adding relay
  • Product group
    • Cancel selection
    • PI-controller
    • P-controller
    • P+PI cascade controller
    • Damper control unit
    • P-controller
    • Pneumatic temperature transducer for duct fitting, centair
    • Room-temperature transducer
    • Average-temperature transducer
    • Outdoor-temperature transducer
    • Pneumatic humidity transducer for wall fitting
    • Pneumatic humidity transducer for duct fitting
    • Differential pressure controller/transducer, centair
    • Manometer for indicating measured values
  • Product group
    • Cancel selection
    • e/p and p/e converter
    • Pneumatic manual switch
    • Pneum. control-pressure adjuster (small cap.)
    • Heavy-duty, pneumatic control-pressure
    • Time-lag relay
    • Pneumatic line restrictor
    • Pressure-reducing station
    • Pieces for push-on pneum. meas. lines
    • Material for pneumatic equipment
    • Pneumatic relay, pluggable
  • Product family
    • Cancel selection
    • Pneumatic drives
    • Regulating valves combined with drive
    • Accessories
  • Product group
    • Cancel selection
    • Pneumatic actuator
    • Pneumatic actuator
    • Pneumatic valve actuator
    • Pneumatic valve actuators
  • Product group
    • Cancel selection
    • 2-way flanged valve, PN 6 (pn.)
    • 3-way flanged valve, PN 6 (pn.)
    • 2-way flanged valve, PN 16/10 (pn.)
    • 3-way flanged valve, PN 16/10 (pn.)
    • 2-way flanged valve, PN 25/16 (pn.)
    • 3-way flanged valve, PN 25/16 (pn.)
    • Pressure-relieved 2-way flanged valve, PN 25 (pn.)
    • 2-way valve with female thread, PN 16 (pn.)
    • 3-way valve with female thread, PN 16 (pn.)
    • 3-way flanged valve, PN 40 (pn.)
    • 2-way flanged valve, PN 40 (pn.)
  • Product group
    • Cancel selection
    • Pneumatic positioner
    • Position alarm/transmitter
  • Product family
    • Cancel selection
    • Engineering (CASE)
    • HVAC automation
    • Operation and indication
    • Room automation
    • Communication and networks
    • System integration
    • Managment level (software)
  • Product group
    • Cancel selection
    • CASE Suite
  • Product group
    • Cancel selection
    • Modular automation station, modu524/525
    • I/O module, digital and universal inputs, modu530
    • I/O module, digital inputs, modu531
    • I/O module, universal inputs, modu532
    • I/O module, universal, digital, S0 inputs, modu533
    • I/O module, digital outputs (relays), modu550
    • I/O module, digital outputs (open collector), modu551
    • I/O module, analogue outputs and universal inputs, modu570
    • I/O module, digital inputs/outputs (open collector), modu571
    • I/O module, analogue outputs, universal and digital inputs, modu572
    • Local operating and indicating units, modu625...670
    • Compact universal automation station, nova230
    • Field module for digital inputs, moduLink174
    • Field module for analogue outputs 0...10 V (0...20 mA), moduLink170
    • Field module for digital outputs 0-I-II, moduLink165
    • Field module for digital outputs 0-I, moduLink164
    • Universal controller, moduFlex
    • I/O module, analogue inputs with galvanic isolation, modu534
    • novaLink module, modu590
  • Product group
    • Cancel selection
    • Local operating unit, modu840
    • Local operating unit, modu240
  • Product group
    • Cancel selection
    • Wireless interface, ecoMod580
    • Push-button unit for room operating unit, ecoUnit306
    • Room operating unit, ecoUnit341...346
    • Room operating unit, ecoUnit310...316
    • Frame for device inserts with 55 × 55 mm fitting dimensions
    • Remote I/O module, ecoLink510...512
    • Remote I/O module, ecoLink520, 521, 526
    • Room automation station, ecos500
    • Room automation station, ecos502
    • Room controller, ecos301, 302
    • Room operating unit, ecoUnit241...246
    • Room operating unit, ecoUnit210...216
    • DDC single-room controller, ecos200
    • DDC single-room controller, ecos202
    • Room operating unit ecoUnit 382 for ecos301/302
    • Remote I/O module, ecoLink522, 523
    • Room operating unit with EnOcean wireless technology, ecoUnit110...146
    • Push-button unit for room operating unit with radio technology, ecoUnit106
    • Room automation station, ecos504/505
    • Power supply unit
    • Touch room operating unit, ecoUnit365
    • Remote I/O module, ecoLink514, 515
    • Remote I/O module, ecoLink527
    • Programmable controller, ecos311
  • Product group
    • Cancel selection
    • Web server for moduWeb Vision and moduWeb500 BACnet networks
    • novaNet-BACnet application master, moduNet300
    • novaNet-Ethernet interface, moduNet292
    • Router, novaNet291
    • OPC server
    • Energy Data Logger for EMS
    • Energy Data Logger for EMS
    • Energy Data Logger for EMS
    • Energy Data Logger for EMS
  • Product group
    • Cancel selection
    • Communication module with EIA-232 and EIA-485 interfaces, modu721
    • Communication module with M-Bus and EIA-232 interfaces, modu731
  • Product group
    • Cancel selection
    • novaPro Open Suite 2017
    • SAUTER EMS and EMS Mobile
    • SAUTER Vision Center