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Quick Start
1. Power on your SRH3 by holding the
ON/OFF button for 1 second.
2. Use the TSH/TEET/NORM button to
select NORMAL mode.
3. Press the RH/DP/WB button to cycle
between relative humidity, dew
point, and wet bulb temperatures.
4. The air temperature will always be
shown in the lower display and the
relative humidity, dew point, or wet
bulb measurement will be displayed
in the upper display in real-time.
5. Insert sensor probe into duct for
in-duct measurements.
Certifications
C-Tick (N22675)
CE
WEEE
RoHS Compliant
Description
With your purchase of the SRH3 you
now have the ability to take supply/
return temperature, %RH, wet bulb
and dew point measurements from
inside the duct or plenum.
Your SRH3 is a portable, hand held,
diagnostic psychrometer, designed
for the HVAC/R technician.
SRH3 helps you properly charge
a fixed restrictor system by quickly
determining the Target Superheat
(TSH). Your SRH3 can also help
determine optimum airflow across
the evaporator by easily performing
a Target Evaporator Exit Temperature
(TEET) test.
The 38"(96cm) telescoping probe
with laser etched ruling and flattened
edges allows you to locate proper
measurement points within a duct and
ensures that your probe is properly
aligned.
The dual display with a bright
backlight, rugged rubber boot with
probe clips, make sure the SRH3 is
ready for any job.
Display
Auto Power Off Enabled
Low Battery Indicator
Relative Humidity
Dew Point
Wet Bulb
Dry Bulb
%Relative Humidity
Outdoor
Indoor
Target Superheat
Target Evaporator Exit Tem-
perature
Normal Range
80
STA2
UNITS
CLEAR DATA
RECORD MODE
PRESS FOR
1 SECOND
In-Duct
Hot Wire
Anemometer
DUCT
ON/OFF
ENTER
HOLD
AVERAGE
MAX/MIN
AUTO-OFF
Temperature (Fahrenheit)
80
STA2
UNITS
CLEAR DATA
RECORD MODE
PRESS FOR
1 SECOND
In-Duct
Hot Wire
Anemometer
DUCT
ON/OFF
ENTER
HOLD
AVERAGE
MAX/MIN
AUTO-OFF
Temperature (Celsius)
Hold Display
Maximum Display
Minimum Display
Fieldpiece
In-Duct
Problem-Solving
Psychrometer
OPERATOR'S
MANUAL
Model SRH3
Controls
Hold 1 second to toggle power on/off.
Toggle Backlight. (Hold while powering
your SRH3 on to disable APO.)
Toggle display to show relative
humidiy, dew point and wet
bulb temperatures
Toggle between Fahrenheit and Celcius.
Hold for 2 seconds to display battery
percentage.
Toggles to display Maximum, Minimum,
or Hold the current reading. Hold for 1
second to exit and clear stored values.
Confirm Selection
Outputs calculations for Target
Superheat or Target Evaporator Exit
Temperature
Toggle to enter Target Superheat,
Target Evaporator Exit Temp, or
Normal modes.
Functions
Backlight
1. Press the backlight button to toggle the backlight
on/off at any time during the SRH3's use.
Note: The back light will automatically shut off after 1
minute to conserve battery life.
Maximum/Minimum/Hold
1. Pressing the MAX/MIN/H button activates the
Max-Min-Hold function, holding the maximum and
minimum measured values until cleared.
2. Once the Max-Min-Hold function has been
enabled, pressing MAX/MIN/H cycles between
displaying maximum (MAX), minimum (MIN) and
freezing the current value.
3. Press and hold the MAX/MIN/H button for 2 seconds
to erases all stored maximum and minimum values
and return to real-time measurements.
Units
1. Press the units button to switch between degrees
Fahrenheit and Celsius.
Battery Check
1. Press and hold the UNIT button for 2 seconds to
display the battery life in percentage.
Output
1. Press the OUTPUT button to perform calculations
of Target Superheat and Target Evaporator Exit
Temperature after necessary measurements have
been entered.
How to Use
Normal Mode
Normal mode allows you quickly
and easily take real-time dry bulb, wet
bulb, dew point, and relative humidity
measurements.
1. Press TSH/TEET/NORM button until NORM is
displayed in lower left corner.
2. For upper display measurements, press the RH/DP/
WB button to toggle relative humidity, dew point,
or wet bulb temperature measurements.
Note: Dry bulb (air temperature) will always show in
the lower display.
Target Superheat Mode
Perform a simple Target Superheat
test to determine what the superheat
should be on a fixed restrictor system.
Use the target superheat to compare
to the actual superheat to determine
if a system is properly charged.
1. Press TSH/TEET/NORM button until TSH is displayed
in the lower left of the LCD.
2. Take a wet bulb measurement at the inlet of the
evaporator. Generally right before the filter is a
good location. Drill or punch a 3/8" hole into the
return plenum for a measurment depth of up to
24 inches. See Figure 1 for recommended return
plenum placement of probe. Insert SRH3 probe into
the plenum to take the wet bulb measurement.
Press ENTER to lock in the reading.
3. Take a dry bulb (air temperature) measurement
going into the condensor. Press ENTER to lock in
the reading.
4. Press OUTPUT to calculate the target superheat.
Compare the target superheat to the actual
superheat of the system.
5. Seal any holes before leaving the jobsite.
Target Evaporator Exit
Temperature Mode
Target Evaporator Exit Temperature
(TEET), aka temperature drop or
delta T, is used to determine if the
evaporator is getting the optimum
airflow. A TEET test can be quickly
performed by taking two easy
temperature measurements at the
return side of the evaporator.
1. Press the TSH/TEET/NORM button until TEET is
displayed in the lower left of the LCD.
2. Take a wet bulb measurement inside the return
plenum. Drill or punch a 3/8" hole into the return
plenum. See Figure 1 for recommended return
plenum placement of probe. Insert SRH3 probe into
the plenum to take the wet bulb measurement.
Press ENTER to lock in the reading.
3. Take a dry bulb measurement at the same place the
previous wet bulb measurement was taken. Press
ENTER to lock in the reading.
4. Press OUTPUT to calculate the target evaporator exit
temperature. Compare this calculated target to the
actual evaporator exit temperature.
5. Take a dry bulb measurement inside the supply
plenum to check the actual Evaporator Exit
Temperature. See Figure 1 for recommended supply
plenum placement of probe. Drill or punch a 3/8"
hole into the supply plenum. Press TSH/TEET/NORM
until NORM is displayed.Insert SRH3 probe into
the plenum and read the temperature in the lower
display.
6. Seal any holes before leaving the jobsite.
Note: For both Target Superheat and Target Evaporator
Exit Temperature modes, you can adjust any
temperature measurement after calculations have
been performed by pressing ENTER. This prompts
you to re-take the measurements.
RCONE1 Probe Lock
Use the RCONE1 to lock your sensor
probe in place inside the duct. Using
the RCONE1 and magnet on the SRH3
allows you hands-free in-duct testing.
See Figure 2.
Specifications
Telescoping Probe Length: Up to 38 inches (97cm)
Probe Tip Diameter: 0.35 inch (9mm)
Storage temperature: -4°F to 140°F (-20°C to 60°C), 0
to 80% RH (with battery removed)
Temperature Coefficient: 0.1 x (specified accuracy)/°C
(<18°C or >28°C)
Over range:
"OL" or "-OL" is displayed
Power: Single standard 9-volt battery, NEDA 1604, JIS
006P, IEC 6F22
Auto Power off:
after 15 minutes of inactivity if APO
is active.
Battery life: 150 hours typical (alkaline)
Low Battery Indication: is displayed when the
battery voltage drops below the operating level.
Dimensions: 7.9 in (H) x 2.6 in (W) x 1.4 in (D),
[200mm (H) x 66mm (W) x 36mm (D)]
Weight: Approx. 400g, including battery
Temperature:
Sensor type: Precision thermistor
Operating environment: -4°F to 140°F (-20°C to 60°C)
Range: -4°F to 140°F (-20°C to 60°C)
Resolution: 0.1°F / 0.1°C
Accuracy: ±(1°F) 32°F to 113°F
±(2°F) -4°F to 32°F, 113°F to 140°F
±(0.5°C) 0°C to 45°C
±(1°C) -20°C to 0°C, 45°C to 60°C
Relative Humidity:
Sensor Type: Capacitance polymer film
Operating environment: 32°F to 131°F (0°C to 55°C)
Range: 0% to 100%RH
Accuracy: ±(2.5%) 10% to 90%RH
±(5%) <10%RH and >90%RH
Note: Above accuracies stated at 73.4°F (23°C).
Sensor Response Time: 60 seconds typical for 90% of
total range.
Sensor Hystersis: ±1%RH typical (Excursion of 10% to
90% to 10%RH)
80
SRH3
PRESS 1 SEC
TO CLEAR
PRESS FOR
1 SECOND
In-Duct
Diagnostic
Psychrometer
UNITS
ON/OFF
TSH/TEET/NORM
RH/DP/WB
AUTO-OFF
BATTERY
CHECK
ENTER
MAX/MIN/H
OUTPUT
80
80
STA2
UNITS
CLEAR DATA
RECORD MODE
PRESS FOR
1 SECOND
In-Duct
Hot Wire
Anemometer
DUCT
ON/OFF
ENTER
HOLD
AVERAGE
MAX/MIN
AUTO-OFF
80
STA2
UNITS
CLEAR DATA
RECORD MODE
PRESS FOR
1 SECOND
In-Duct
Hot Wire
Anemometer
DUCT
ON/OFF
ENTER
HOLD
AVERAGE
MAX/MIN
AUTO-OFF
80
STA2
UNITS
CLEAR DATA
RECORD MODE
PRESS FOR
1 SECOND
In-Duct
Hot Wire
Anemometer
DUCT
ON/OFF
ENTER
HOLD
AVERAGE
MAX/MIN
AUTO-OFF
80
STA2
UNITS
CLEAR DATA
RECORD MODE
PRESS FOR
1 SECOND
In-Duct
Hot Wire
Anemometer
DUCT
ON/OFF
ENTER
HOLD
AVERAGE
MAX/MIN
AUTO-OFF
RH/DP/WB
UNITS
BATTERY
CHECK
PRESS 1 SEC
TO CLEAR
MAX/MIN/H
ENTER
OUTPUT
TSH/TEET/NORM
ON/OFF
Recommended Hole
Placement for Supply
Plenum Measurements
Recommended
Hole Placement for
Return Plenum
Measurement is
directly before the
evaporator coil. Look behind
the panel before drilling and make
sure you do NOT drill a hole through any critical HVAC compo-
nents.
Figure 1
SRH3
PRESS 1 SEC
TO CLEAR
PRESS FOR
1 SECOND
In-Duct
Diagnostic
Psychrometer
UNITS
ON/OFF
TSH/TEET/NORM
RH/DP/WB
AUTO-OFF
BATTERY
CHECK
ENTER
MAX/MIN/H
OUTPUT
ARH5
In-Duct
Psychrometer
Head
ON
AUTO OFF
1%RH/mVDC
1°F/mVDC
1°C/mVDC
LO BATT
DEW POINT
%RH
WET BULB
TEMP
°F
°C
ON
OFF
ET2W
LO BATT
SEND
RECEIVE
ON
AC
DC
Wireless
Transmitter
SYNC
Clear
Input
Output
Recall
Enter
Save
Sync
SETUP
Target
Evaporator
Logger
Light
Exit Temp
CFM
Display
Superheat
Subcooling
Combustion
HVAC Guide
CheckMe!
Fieldpiece
HG3
Data
Service
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INPUT FORM
SH Table: Standard
Refrigerant: R-22
OD Dry Bulb:
85.4°F
Return WB:
63.0°F
SL Pressure:
52.4psig
SL Temp:
45.4°F
CustomerID:
__JONES123
Use the RCONE1 for
hands-free in-duct
measuremesnts.
Figure 2
WARNING
Do not retract the sensor probe by pulling on the cord.
Doing so may sever the cord from the sensors.
