HK Instruments RHT DUCT Series Installation Instructions

INTRODUCTION
Thank you for choosing an HK Instruments RHT Duct series relative
humidity transmitter. The RHT series is intended for use in commer-
cial environments in HVAC/R applications.
RHT Duct is a relative humidity transmitter with temperature output
installed in air ventilation duct. In addition to these measured values,
RHT Duct calculates various parameters such as dew point, mixing
ratio, enthalpy and absolute humidity. Illuminated display ensures
easy readability also from a distance. The RHT has a screwless lid
and an easily adjustable mounting flange that make the installation
of the device easy.
APPLICATIONS
RHT Duct series devices are commonly used to monitor and control:
• Relative humidity and temperature levels of incoming and return air
in ventilation system
SPECIFICATIONS
Performance
Measurement ranges:
Temperature: -30...80 °C, sensor
Relative humidity: 0–100 %
Accuracy:
Temperature: <0.5 ºC
Relative humidity: ±2...3 % at 0...50 °C and 10–90 % rH
Total error band includes accuracy, hysteresis and
temperature effect over 5...50 °C and 10–90 % rH.
Technical Specifications
Media compatibility:
Dry air or non-aggressive gases
Measuring units:
°C and % rH
Measuring element:
Temperature: NTC10k
Relative humidity: Thermoset polymer capacitive
sensing element
Environment:
Operating temperature: 0...50 °C
Storage temperature: -20...70 °C
Humidity: 0 to 95 % rH, non condensing
Copyright HK Instruments 2021
HUMIDITY TRANSMITTERS
RHT Duct Series
• READ THESE INSTRUCTIONS CAREFULLY BEFORE
• Failure to observe safety information and comply with
• To avoid electrical shock or damage to equipment, disconnect
• To avoid potential fire and/or explosion do not use in potentially
• Retain these instructions for future reference.
• This product, when installed, will be part of an engineered
Physical
Dimensions:
Case: 119 x 95.5 x 45 mm
Probe: L=188 mm, d=12 mm
Mounting:
With flange, adjustable 40...155 mm
Weight:
150 g
Materials:
Case: ABS
Cover: PC
Probe: ABS
Mounting flange: LLPDP
Protection standard:
IP54
Electrical connections:
4 spring loaded terminals
(24 V, GND, OUT1*, OUT2*)
0.2–1.5 mm (16–24 AWG)
2
A-model:
2 additional spring loaded terminals
for mA-output (OUT1*, OUT2*)
0.2-1.5 mm (16-24 AWG)
2
*Default OUT1=rH, OUT2=TE
Outputs selectable on the display:
temperature / dew point / mixing ratio /
enthalpy / absolute humidity / relative humidity
www.hkinstruments.fi
WARNING
ATTEMPTING TO INSTALL, OPERATE OR SERVICE THIS
DEVICE.
instructions can result in PERSONAL INJURY, DEATH AND/OR
PROPERTY DAMAGE.
power before installing or servicing and use only wiring with
insulation rated for full device operating voltage.
flammable or explosive atmospheres.
system whose specifications and performance characteristics
are not designed or controlled by HK Instruments. Review
applications and national and local codes to assure that the
installation will be functional and safe. Use only experienced and
knowledgeable technicians to install this device.
Electrical
Supply voltage: 24 VAC or VDC ±10 %
Current consumption: max 90 mA (at 24 V) + 10 mA for
each voltage output
Output signals for every media:
0/2...5/10 VDC, Load R minimum 1 kΩ
Only A-model:
4...20 mA, Load R maximum 500 Ω, minimum 20 Ω
Output calibrated within ±0.08 mA
Conformance
Meets the requirements for:
EMC:
RoHS:
WEEE:
INSTALLATION
INSTRUCTIONS
CE: UKCA:
2014/30/EU S.I. 2016/1091
2011/65/EU S.I. 2012/3032
2012/19/EU S.I. 2013/3113
Installation version 8.0 2021
RoHS
COMPLIANT