Triplett RHT70 User manual

User Manual
RHT70
Hygro-Thermometer + IR Thermometer

Introduction
Congratulations on your purchase of the Triplett RHT70 Hygro-
Thermometer plus InfraRed Thermometer. This device measures relative
humidity, air temperature (with probe), and surface temperature (with the
InfraRed function). The large, easy-to-read backlit LCD includes primary
and secondary displays plus numerous status indicators. The InfraRed
feature includes a laser pointer for convenient targeting.
Safety
Use extreme caution when the laser pointer beam is on
Do not point the beam toward
anyone's eye or allow the beam to
strike the eye from a reflective
surface
Do not use the laser near
explosive gases or in other
potentially explosive areas
Meter Description
1. Humidity/Air Temperature Probe
2. Probe input jack
3. Laser pointer
4. IR Sensor
5. Rubber holster
6. LCD Display
7. IR thermometer measurement button
8. IR and Relative Humidity function buttons (4)
9. Air Temperature function buttons (3)
10. Probe holder
11. Power ON/OFF button
12. Backlight button

Note: The battery compartment, tilt stand, tripod mount, and probe
holder removal screw are located on the rear of the instrument
Display Description
MAX (top of LCD): Max Hold function engaged for the Air
Temperature function
HOLD (top of LCD): Data Hold
function engaged for the Air
Temperature function
PROBE TEMP: Reminder that
the top LCD digits represent Air
(Probe) Temperature
: Indicates that the laser
pointer is on.
IR TEMP: Indicates that the
larger LCD digits represent IR
temperature measurement
MAX (bottom of LCD): Max Hold for the IR Temperature and RH
function
HOLD (bottom of LCD): Data Hold for the IR Temperature function
and RH function
oC / oF: Temperature units of measure
%RH: Relative Humidity unit of measure
Large LCD digits at center of display for Relative
Humidity and IR Temperature Smaller LCD digits
at top, right of display for Probe Temperature
: Low battery indicator

Operation
Power
Press the button to turn power on or off.
Probe Humidity and Temperature Measurements
1. Attach the probe to the meter via the jack at the top of the meter.
2. Hold the probe in the area to be tested & allow adequate time for readings
to stabilize.
3. Read the Relative Humidity (center of LCD) and Probe
Temperature (top of LCD). NOTE: Do not immerse the probe in liquid;
it is intended for use in air only.
InfraRed (Non-Contact) Temperature Measurements
1. The IR sensor is located at the top of the meter.
2. Point the sensor toward the surface to be measured.
3. Press and hold the large red IR button to begin
measuring the surface temperature of a desired target.
IR TEMP and will appear on the display. The laser
pointer will switch on to help aim the meter.
4. The measured IR surface temperature will appear at
the center of the LCD (larger digits). The temperature
displayed is the temperature of the area within the spot.
5. When the red IR button is released, the laser pointer
will switch off and the reading will freeze (data hold) on
the display for approx 10 seconds.
6. Note that the probe (Air Temperature wand) continues to
monitor temperature during IR tests and its temperature
is displayed on the top of the LCD (smaller
digits).
7. After approx. 10 secs. the meter defaults to the
Humidity and Air Temperature display.

Automatic Power OFF
To conserve battery life the meter automatically shuts off after 10 minutes.
oF/oC buttons
The Air Temperature and the IR Temperature units can be selected
by the user. For Air Temperature, press the oF/oC button on the
bottom left. For the IR temperature units, press the oF/oC button at
the center of the meter.
Data Hold Buttons
Displays can be held (frozen) at any time by pressing the HOLD button.
For Air Temperature, use the HOLD button on the bottom right. For IR
Temperature and for Relative Humidity, use the HOLD button on the right
center of the meter. Press HOLD again to exit the mode. Note that in IR
temperature mode Data Hold is automatically engaged when the red IR
button is released.
MAX Buttons
Press the MAX button (bottom of meter for Air Temperature; center of
meter for IR temperature and Relative Humidity) to display only the
highest reading. The displayed measurement will now only change when
a higher reading is detected. Press the MAX button again to exit this
mode.
Backlight Press the backlight button to turn the light on. Press again to
turn it off.
The polarization index Test calculates the ratio of the resistance
measurement after 10 minutes to the resistance measurement after 1
minute: Results are determined by the type, age and condition of the
insulation material tested. Established standards and test procedures
should be used to establish pass/fail criteria for each application.

InfraRed Measurement Considerations
When taking IR measurements the meter automatically
compensates for ambient temperature changes. Note that it may
take up to 30 minutes to adjust to extremely wide ambient
changes.
Low temperature measurements quickly followed by high
temperature measurements may require several minutes to
stabilize as a result of the IR sensor cooling process.
If the surface of the object under test is covered with frost, oil,
grime, etc., clean before taking measurements.
If an object's surface is highly reflective apply masking tape or flat
black paint before measuring. Steam, dust, smoke, etc. can obstruct
measurements.
To find a hot spot, aim the meter outside the area of interest then
scan across (in an up and down motion) until the hot spot is
located.
IR Theory
IR thermometers measure the surface temperature of an object. The
meter’s optics sense emitted, reflected, & transmitted energy that is
collected and focused onto the meter’s detector. The meter’s circuitry
translates this information into an LCD reading.
IR Field of View
Ensure that the desired target is larger
than the spot size as shown in the
diagram below. As the distance from an
object increases, the spot size of the
area measured by the meter becomes
larger. The meter’s field of view ratio is
8:1, meaning that if the meter is 8 inches
from the target, the diameter (spot) of the object under test must be at
least 1 inch. Other distances are shown below in the field of view diagram.

Maintenance
Cleaning and storage
1. The meter should be cleaned with a damp cloth and mild detergent
when necessary. Do not use solvents or abrasives.
2. Store the meter in an area with moderate temperature and humidity.
Battery Replacement
The battery symbol appears on the lower right of the LCD when
the 9V battery needs to be replaced.
Replace the 9V battery as follows:
1. Turn the meter off and disconnect the air temperature probe.
2. Remove the large flat-head screw on the rear of the meter to remove
the probe holder.
3. Remove the rubber holster that surrounds the entire meter by pulling it over
the top of the meter.
4. Remove the small Phillips head screw on the rear of the meter.
5. Open the battery compartment and replace the 9V battery.
6. Re-assemble the meter before operating.
Never dispose of used batteries or rechargeable batteries in
household waste.
As consumers, users are legally required to take used
batteries to appropriate collection sites, the retail store
where the batteries were purchased, or wherever
batteries are sold.
Disposal: Do not dispose of this instrument in household waste. The user
is obligated to take end-of-life devices to a designated collection point for
the disposal of electrical and electronic equipment.
Other Battery Safety Reminders
oNever dispose of batteries in a fire. Batteries may explode or leak.
oNever mix battery types. Always install new batteries of the same type.

WARNING: To avoid electric shock, do not operate the meter until the
battery cover is in place and fastened securely.
NOTE:: If your meter does not work properly, check the fuses and batteries
to make sure that they are still good and that they are properly
inserted.
Calibration
A humidity calibration adjustment is located in the battery compartment.
1. Remove the battery door and move the battery to one side.
2. Place the humidity probe in a humidity chamber or humidity calibration
bottle and wait 20 minutes
3. Turn the meter on and turn the adjustment until the humidity reading
on the display agrees with the calibration source.
Specifications
Function
Range and Resolution
Accuracy
Humidity
10.0 to 95.0% RH
± 3.5% RH
Air
Temperature
-20 to 60oC (-4 to 140oF)
± 2.0oC (± 3.0oF)
IR
Temperature
-50.0 to -20.0oC (-58.0 to -
4.0oF)
± 5oC (± 9oF)
-20.0 to 93.3oC (-4.0 to
199.9oF)
± 2% of rdg or ± 2oC (±
4oF)
93oC to 204oC (200 to
400oF)
204oC to 500oC (400 to
932oF)
± 3% of rdg
Display
Dual LCD with Backlight and status indicators
Sensor Type
Humidity: Precision capacitance sensor
Temperature: Thermistor (probe) and InfraRed

Response
Time
IR Temperature: 0.5 seconds; Probe Temperature
and Relative
Humidity: 3 minutes
Accuracy note
Accuracy is specified for the following ambient
temperature range: 18 to
28°C (64 to 82°F)
Sampling
Rate
2.5 samples per second
InfraRed
Emissivity
0.95 (fixed)
IR Field of
View
D/S = Approx. 8:1 ratio (D = distance, S = spot)
Laser power
Less than 1mW
IR Spectral
Response
6 to 14 m (wavelength)
Operating
Conditions
0 to 50oC (32 to 122oF); < 80% RH non-condensing
Storage
Conditions
-10 to 60oC (14 to 140oF); <80% RH non-condensing
Power Supply
9V Battery with auto power off (after 10 minutes)
Battery Life
Approx. 24 hours (if Backlight and Laser are used
continuously the
battery life is reduced to 2 to 3 hours approx.)
Dimensions /
Weight
150 x 72 x 35mm (5.9 x 2.8 x 1.4”); 235g (8.3 oz)
Emissivity
Most organic materials and painted or oxidized surfaces have an
emissivity of 0.95 (fixed setting in the model RHT70). Inaccurate
readings will result when measuring shiny or polished surfaces. To
compensate, cover the surface under test with masking tape or flat black
paint. Allow time for the tape to reach the same temperature as the
material underneath then measure the temperature of the tape or the
painted surface.

Warranty
Triplett / Jewell Instruments extends the following warranty to the original purchaser of
these goods for use. Triplett warrants to the original purchaser for use that the products
sold by it will be free from defects in workmanship and material for a period of (1) one
year from the date of purchase. This warranty does not apply to any of our products
which have been repaired or altered by unauthorized persons in any way or purchased
from unauthorized distributors so as, in our sole judgment, to injure their stability or
reliability, or which have been subject to misuse, abuse, misapplication, negligence,
accident or which have had the serial numbers altered, defaced, or removed.
Accessories, including batteries are not covered by this warranty
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