Series HHT Hazardous Area Humidity/Temperature Transmitter

Intrinsically Safe or Explosion-Proof Models

The Series HHT Hazardous Area Humidity/Temperature Transmitter takes accurate measurements in the harshest of environments. The explosion-proof model is offered with 4 to 20 mA output for humidity only. The intrinsically safe version is offered with 4 to 20 mA output for humidity and temperature, and do require an intrinsically safe barrier to meet hazardous area approvals.

Product Applications

Process monitoring
Offshore HVAC monitoring
Dust and grain handling

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Models & Ordering

Shipping Information

All shipping times are dependent on product availability at time of shipment.

Although we make every effort to ensure a continuous supply of our products, occasional circumstances may force us to temporarily run out of a product, or have shipping delays. Should this occur, customers will be notified soon after placement of any orders for such products and, if applicable, items will be put on backorder. For orders requiring expedited shipment, our customer service team can be contacted to confirm product availability

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Model	Description	Usually Ships*	Price	Order
HHT-EU Ships: Next Day Price: $1,570.00	Explosion-proof humidity transmitter.	Next Day*	$1,570.00	Order
HHT-EU-LCD Ships: Next Day Price: $1,672.00	Explosion-proof humidity transmitter with LCD display.	Next Day*	$1,672.00	Order
HHT-IT Ships: Next Day Price: $1,249.00	Intrinsically safe humidity/temperature transmitter.	Next Day*	$1,249.00	Order
HHT-IT-LCD Ships: Next Day Price: $1,351.00	Intrinsically safe humidity/temperature transmitter with LCD display.	Next Day*	$1,351.00	Order
HHT-IU Ships: 1-2 Weeks Price: $1,194.00	Intrinsically safe humidity transmitter.	1-2 Weeks*	$1,194.00	Order

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Specifications

Relative Humidity Range:: 0 to 100% RH.
Temperature Range:: -40 to 140°F (-40 to 60°C).
Accuracy:: ±2% 10 to 90% RH, ±0.9°F at 72°F (±0.3°C at 25°C).
Hysteresis:: ±1%.
Repeatability:: ±0.1% typical.
Temperature Limits:: -40 to 140°F (-40 to 60°C).
Storage Temperature:: -40 to 176°F (-40 to 80°C).
Compensated Temperature:: -40 to 140°F (-40 to 60°C).
Power Requirements:: For instrinsically safe models HHT-IX, 9.5 to 28 VDC. For explosion-proof models HHT-EX, 16.5 to 28 VDC.
Output Signal:: 4 to 20 mA, 2 channels for humidity/temperature models (loop power on RH).
Response Time:: 15 s.
Electrical Connections:: Screw terminal block.
Conduit Connection:: 1/2" female NPT.
Drift:: <1% RH/year.
RH Sensor:: Capacitance polymer.
Temperature Sensor:: Solid state band gap.
Housing Material:: Aluminum.
Display:: Optional 2 line alpha numeric, 8 characters/line. Temperature display is °F/°C selectable.
Display Resolution:: RH: 0.1%; Temperature: 0.1°F (0.1°C).
Weight:: 2 lb 8 oz (1134 g).
Enclosure Rating:: NEMA 4X (IP66). Models HHT-EX: FM Explosion-proof, Class I Div. 1 Group B, C, D, Class II Div. 1 Group E, F, G, Class III Div. 1; Models HHT-IX: FM Instrinsically Safe, Class I Div. 1 Group A, B, C, D, Class II Div. 1 Group E, F, G, Class III Div. 1 T4.
Agency Approvals:: FM, CE.

Features

FM approved explosion-proof and intrinsically safe models
Integral LCD option
Dual temperature and relative humidity output models

Accessories

Model Number	Description	Usually Ships*	Price	Order
KFD0-SCS-EX1.55	Loop powered galvanic barrier for use with intrinsically safe transmitters.	Next Day	$677.00	Order
A-287	Mounting bracket for pipe or surface mounting (includes bracket and two 2" U-bolts).	Next Day	$55.00	Order
A-450	Replacement sintered filter for Series HHT	Next Day	$10.50	Order
A-451	Replacement 2% sensor for Series HHT (for models built after April 2019).	1-2 Weeks	$105.00	Order

Videos

Liquid in your Housing? How to Prevent Conduit Condensation

Model Chart

HHT-XX-OPT    HHT HUMIDITY HUMIDITY/TEMP TRANSMITTER

          1ST SYMBOL (1ST X) APPROVAL
             A     ATEX/IECEX FLAMEPROOF (NOT AVAILABLE)
             E     FM EXPLOSION PROOF
             I     FM INTRINSICALLY SAFE

          2ND SYMBOL (2ND X) PROCESS CONNECTION AND OUTPUTS
             B     1/2 IN MALE BSPT HUMIDITY
             E     1/2 IN MALE BSPT HUMIDITY AND TEMPERATURE (I ONLY)
             T     1/2 IN MALE NPT HUMIDITY AND TEMPERATURE (I ONLY)
             U    1/2 IN MALE NPT HUMIDITY

          OPTION (OPT)
            -C5    C5-M HOUSING PAINT SPECIFICATION
            -LCD   LCD DISPLAY
            -M20   M20 CONDUIT HOUSING
            -FC    FACTORY CALIBRATION CERTIFICATE

Product Literature

Manuals

Instruction Manual

Catalog Pages

Series HHT Catalog Page

Approvals

Drawings

Questions

Question

I'm looking for a dual temp. and humidity gauge for an 8" duct. I'm wanting to remote read the temp and humidity on the incoming and outgoing air to an ERV unit. The RHP-3M11-LCD was recommended to me, however, it is a direct read. What would be the correct instrument to remote read the temperature and humidity from a distance of 8 feet. The 8" duct is in the attic and I want to read the result in the down-stair hall. I don't want to record nor program the unit, just read the performance.

Answer

The sensor recommended would be the best option we have for sensing temperature and relative humidity for your application. We do not have any options with a remote display that could stretch as far as you are asking, nor are there any on the market to my knowledge. In every case, you would need to utilize a process output, in this case 4-20 mA, to transmit the readings to a remote display(s) which would accept the process signal(s). If you are just looking for a remote readout to go with the RHP sensor with no control functionality, then you could look at one of our panel meters, possibly the SPPM, DPMA, DPMW, or DPMP & DPML series panel meters. For assistance selecting an appropriate panel meter, please contact our technical support group at 219-879-8000.

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