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Fieldpiece JL3RH Flex Psychrometer Probe


Available on backorder

FREE delivery over $99

Easy 30 day return (Domestic)

Easy International shipping

Need Help? Speak with our HVAC and tools experts. Call or text (786) 239-7444.


The Fieldpiece JL3RH Job Link Flex Psychrometer Probe has a long flexible wand and a strong sliding magnet for easy measurements anywhere on the system. The JL3RH psychrometer measures dry bulb, wet bulb, %RH, dew point, and enthalpy. Get instant live readings from ducts, plenums, registers, and grilles, or walk around for accurate diagnostics. Now handles extreme duct temperatures up to 250°F and as low as -40°F! Return and supply indicator switch ensures you’re recording the proper measurements in the correct place.

Also, you can connect your Fieldpiece JL3RH wireless psychrometer directly to the Job Link app and the wireless SMAN™ Refrigerant Manifolds (3-port SM380V or 4-port SM480V) to see live air temperatures readings while you’re making adjustments to the system. Furthermore, data log results in the manifolds or Job Link System reports. Remote Data Logging sends air measurements to the Fieldpiece Job Link app up to 1000′ away!

Bend the flexible probe and slide the magnet to configure the Fieldpiece psychrometer probe to your situation conveniently. The rubberized protective housing of the JL3RH is both ergonomic and rugged for daily use. Flip the switch, and the Job Link app immediately knows which side of the system you will place your Fieldpiece Psychrometer. Use the JL3RH for its long wireless range, strong magnet, and flexible probe for quick and easy psychrometrics testing.

Fieldpiece job link probes are sold as individuals so that you can use one or more at a time, or they come included in the Job Link Probes Charge and Air Kit.

  • Fieldpiece Psychrometer JL3RH Flex Probe
  • Powerful 1000′ wireless range w/no transmitter required
  • Place in critical locations based on system needs
  • Requires only a 3/8” hole for duct testing
  • Flex wand and strong adjustable magnet for hands free measurements
  • Measures %RH, dry and wet bulb, dew point, and enthalpy
  • Communicates with Job Link App and Wireless Manifolds (SM380V/SM480V)
  • Powerful enough to go through most walk-in coolers and freezers
  • Strong magnetic hanger
  • Supply and return side switch
  • Water resistant
  • LED color indications
  • Rapid Rail sensor advantage
  • Remote Data Logging
  • 1 Year Limited Warranty
Fieldpiece Psychrometer JL3RH Flex Probe
Minimum Device Requirement : BLE 4.0 devices running iOS® 7.0 or Android™ 5.0 (Latest compatibility at
Battery Type : 2 x AAA, NEDA 24A, IEC LR03
Battery Life : 150 hours typical alkaline. LED blinks red when battery replacement is needed.
Auto Power Off : 2 hours (APO can be disabled)
Wireless Range : 1000 feet (305 meters) line of sight. Obstructions affect distance.
Radio Frequency : 2.4 GHz
Operating Environment : 32°F to 122°F (0°C to 50°C) at <75% RH
Storage Temperature : -4°F to 140°F (-20°C to 60°C), 0 to 80% RH (with batteries removed)
Temperature Coefficient : 0.1 x (specified accuracy) per 1.8°F (32°F to 64°F, 82°F to 122°F), per 1°C (0°C to 18°C, 28°C to 50°C)
Weight : 0.33 lbs (150 g)
Flexible Probe : 0.36″ (9mm) diameter; 9.25″ (235mm) length
Relative Humidity (%RH) :
  • Sensor Type: Capacitance polymer film
  • Hysteresis: ±1%RH typical (Excursion of 10% to 90% to 10%RH)
  • Measurement Range: 0%RH to 100%RH
  • Accuracy: (At 73.4°F (23°C)) ±2.5% (10%RH to 90%RH); ±(5%) <10%RH, >90%RH
  • Response Time: 60 seconds typical for 90% of total range
Temperature :
  • Sensor Type: Precision thermistor
  • Measurement Range: -40°F to 250°F (-40°C to 121°C)
  • Accuracy: ±(1°F) 32°F to 113°F, ±(0.5°C) 0°C to 45°C; ±(2°F) -4°F to 32°F, 113°F to 140°F, ±(1°C) -20°C to 0°C, 45°C to 60°C
What is the warranty on these fieldpiece probes?

1 Year Limited Warranty for all probes. Fieldpiece specifically states, “In the USA, your Fieldpiece meters, standalone instruments, accessory heads, and pocket tools are warranted against defects in material or workmanship for one year from date of purchase. Fieldpiece will replace or repair the defective unit, at its option, subject to verification of the defect. This warranty does not apply to defects resulting from abuse, neglect, accident, unauthorized repair, alteration, or unreasonable use of the instrument."

Is the job link app free?

It will show all the readings plus some simple calculations free regardless of subscription or not. The subscription adds extra features for businesses like creating invoices plus advanced calculations.

Is this JL3RH fieldpiece wireless psychrometer compatible with MeasureQuick?

Yes, the MeasureQuick app is compatible with all Fieldpiece Job Link probes.

  • (1) Fieldpiece JL3RH Job Link Flex Psychrometer Probe
  • (1) Protective Slip Cover for Sensor Tip
  • (2) AAA Batteries
  • (1) Operator’s Manual

Customer Reviews

Based on 1 review
Derek H.
Top of the line product

These psychrometers work really well especialy if you have two. It has a long range and great battery life.

Fieldpiece JL3RH
Fieldpiece JL3RH Flex Psychrometer Probe