Part Number: 65-9082


The H-Guard-L is a CO2 transmitter series designed to be installed in HVAC applications.

List of Benefits

  • Special used to real-time detect CO2 level in air ducts.
  • NDIR infrared CO2 sensor inside with Self-Calibration and up to 15 years lifetime
  • Humidity and temperature detection optional
  • Combined temperature and humidity sensor provide the highest accuracy in full range
  • Backlit LCD display option can display CO2 measurement and temperature+ RH measurements
  • Providing one or three 0~10VDC or 4~20mA or 0~5VDC analog outputs
  • Modbus RS485 communication interface makes usage and test more convenient
  • Smart structure and attractive housing provide you a unique operation feeling
  • Simple and skillful design and installation with a demountable and replaceable filter to provides dust-proof protection
  • Special a 180° rotatable fastness position for the probe can change the direction of air detection.
  • All housing and probe are IP54 class
  • CE-Approval


The CO2 sensing element uses the Non-Dispersive Infrared Technology (NDIR) with the patented self-calibration system to guarantee the long term stability and up to 15 years life time. H-Guard-L duct probe transmitter offers temperature and humidity option. The high accuracy temperature and humidity combined sensor provide a digital interface and outstanding full range linearity. The one or three analogue 0-10V or 4~20mA outputs are selectable by jumpers. Modbus RS485 communication interface is provided. Optional backlit LCD can display all measurements and is usable easily in more applications. H-Guard-L offers simplicity in design and installation with the special  demountable and replaceable filter to avoid pollution and influence of measurement.

Available Models/ Parts

  • 65-9082     : H-Guard-L CO2 transmitter wall mounting with the adown external sensor probe. 1x4-20mA output for CO2. Modbus interface. LCD display, CO2 range: 0-2000ppm, power supply 24VAC/VDC.
  • 65-9082-10: H-Guard-L CO2 transmitter wall mounting with the adown external sensor probe. 3x4-20mA output for CO2+T+H. Modbus interface. LCD display, CO2 range: 0-2000ppm, power supply 24VAC/VDC.
  • 49-9998-01 : Plug pack 240VAC/24Vdc 450mA
SpecificationDetail Description
Gas detectedCarbon Dioxide (CO2)
Sensing elementNon-Dispersive Infrared Detector (NDIR)
Accuracy@25(77),2000ppm ±40ppm + 3% reading
Stability<2% of FS over life of sensor (15 yr typical)
Calibration interval ABC Logic Self Calibration System
Response time<2 minutes for 90% step change
Warm up time2 hours (first time) 2 minutes (operation)
CO2 measuring range0-2,000ppm / 0-5,000ppm selectable in orders, 0-20,000ppm / 0-50,000ppm just for TSM-CO2-S series
Sensor lifeUp to 15 years
Power supply24VAC/24VDC
Consumption1.5 W max. ; 0.8 W avg.
Analog outputs0~10VAC or 4~20mA selectable by jumpers
Relay output1X3A switch load Four set points selectable by jumpers
Modbus interfaceModbus RS485 interface 9600/14400/19200(default)/28800 or 38400bps (programmable selection), 15KV antistatic protection.
Operation conditions0~50(32~122); 0~95%RH, non condensing
Storage conditions-40~70(-40~158)
Net weight180g
Installation standard65mm×65mm or 2”×4”wire box

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