Extech Instruments HD750 User manual

USER GUIDE
Heavy Duty
Differential Pressure Manometer
Model HD750
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Introduction
Congratulations on your purchase of the Extech Manometer Model HD750. This device measures
gauge and differential pressure in the range of ±5.000 psi. The HD750 offers eleven (11) units of
measure (user selectable by front panel pushbutton) and has a differential input that uses
convenient quick disconnect fittings. Advanced features include DATA HOLD, MIN MAX AVG
RECORD mode, ZERO/OFFSET, AUTO POWER OFF, and USB PC interface. This meter is shipped fully
tested and calibrated and, with proper use, will provide years of reliable service. Please visit our
website () to check for the latest version of this User Guide, Product Updates, and
Customer Support.
Meter Description
1. P1 input
2. AC adaptor jack
3. P2Input
4. LCD Display Indicates the measurement data, unit of measure,
elapsed timer, and function symbols as described in this manual
5. USB PC interface jack (3.5mm) For use with data acquisition
software
6. UNIT button Press to select the unit of measure
7. DIF  button Press to display differential pressure. Also used to
OFFSET the displayed readings.
8. RECORD  button Press to access the MIN/MAX/AVG recording
mode
9. HOLD / ZERO  button Press to freeze the displayed reading. Also
used to zero the display (press and hold until display shows all
zeroes).
10. BACKLIGHT
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Display
1. USB data output active
2. Differential Pressure Mode
3. Data Hold Mode
4. Primary display
5. Record Mode
6. MAX/MIN/AVG indicators
7. Low Battery Indicator
8. Pressure unit of measure
9. Elapsed Timer
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Basic Operation
Meter Power
The HD750 uses a 9V battery for power. If the meter does not switch on when the POWER
button is pressed or if the display shows BAT, replace the battery.
When the POWER buttons is pressed, the meter performs a short self test and reverts to the
settings in place when the meter was last turned off.
Automatic Power off Feature
In order to conserve battery life, the meter has an automatic power off feature (after 20
minutes). To defeat this feature, press and hold the HOLD button while turning the meter on.
Release the HOLD button when   n appears on the display. The meter will now remain on until
the user turns it off or until the battery weakens. Note that the Auto Power OFF feature will be
reactivated the next time the meter is turned off and then on.
Unit of Measure
Press the UNIT button to select the unit of measure. This meter offers eleven (11) units of
measure as listed below.
Unit of Measure Display icon
Pounds per square inch psi
Inches of Mercury inHg
Milli bar mbar
Millimeters of Mercury mmHg
Kilo Pascals kPa
Kilograms per centimeter squared Kgcm2
Inches of water inH2O
Feet of water ftH2O
Centimeters of water cmH2O
Bars Bar
Ounces per square inch ozin2
Fittings Connection
Connect tubing to the P1, P2 (or both) input port(s). If both inputs are used (differential mode),
the meter displays a positive pressure reading if the P1 pressure is greater than P2 and a
negative reading if P2 is greater than P1.
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Zero Adjust and Offset function
The unit must be kept in the upright position when ZEROING or when taking measurements. To
ZERO the meter: Before use and without fittings attached to the meter, press and hold the HOLD
button for 3 seconds or until the display shows all zeroes.
To OFFSET meter readings: Press the DIF button while taking a measurement. Subsequent
readings will represent the difference between the current measurement and the measurement
that was on the display when the DIF button was pressed.
MIN MAX AVG Record Mode with Elapsed Timer
The RECORD function tracks the maximum (MAX), minimum (MIN), and average (AVG) readings
with a time stamp. The elapsed timer is displayed on the lower right hand corner of the LCD and
informs the user of the time a MAX or MIN reading was recorded.
1. Press the RECORD button once. The REC indicator will appear on the display and the
displayed elapsed timer will start (HH:MM:SS format [hours:minutes:seconds]).
2. Press the RECORD button again to view the highest (MAX) reading recorded since the
RECORD button was first pressed. The MAX indicator and maximum reading will appear on
the display. The elapsed timer will show the time of the MAX event.
3. Press the RECORD button again, the MIN indicator and the minimum value will appear on
the display. The elapsed timer will show the time of the MIN event.
4. Press the RECORD button again, the AVG indicator and the average value will appear on the
display. The elapsed timer will continue to run.
5. To return to normal operation, press and hold the RECORD button until the display
indicators REC, MAX, etc. switch off.
Note that in the RECORD mode, the backlight and the power buttons are the only available
functions.
USB PC Interface
The meter has a built in USB port for use with the Manometer Data Acquisition software. The
software allows the user to view, save, export, and print readings from the HD750. Refer to the
documentation included with the software for complete details.
Displayed Error Codes
The following codes are displayed when the meter encounters an error.
ERR 1: Pressure input exceeds specified limits
ERR 2: Pressure input is too low to read
ERR 3: The Differential Pressure input exceeds specified limits
ERR 4: The Differential Pressure input is too low to read
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Specifications
General Specifications
Display Four digit LCD with function indicators
Units of Measure BAR, mBAR, psi, kg/cm2, mm Hg, inches Hg, kPa, feet H2O, inches
H2O, cm H2O, and oz in2
Accuracy ±0.3%FS (@ 25°C)
Repeatability ±0.2% to 0.5% FS
Linearity/Hysteresis ±0.3%FS
Combined Accuracy ±1.1%FS
Maximum Pressure 10psi
Response time 0.5s typical
Input circuit Differential inputs (P1 and P2)
Input Ports Two metal 4.8mm, barbed for 1/8" (3.17mm) ID tubing
Data Hold Freezes displayed reading
Sensor Built in piezoelectric sensors
Zero / Offset function Pushbutton activation
Sample rate 0.5 sec. (approx.)
Compatibility Air or non corrosive and non ionized gas (not intended for use with
liquids)
Auto Power OFF Meter turns off after approx. 20 minutes to conserve energy (can
be deactivated)
PC Interface Built in USB serial interface
Storage conditions 0 to 60oC (14 to 140oF); < 80% RH
Operating conditions 0 to 50oC (32 to 122oF); < 80% RH
Battery power 9V alkaline battery (BAT low battery indicator)
Battery life 125 hours typical
Dimensions 210 x 75 x 50mm (8.2 x 2.9 x  1.9 )
Weight 280g (9.8oz)
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Range Specifications
Range/Units (Max.) Resolution
± 0.344bar 0.001
± 344.7mbar 0.1
± 5.000psi 0.001
± 0.351Kg/cm20.001
± 258.5 mm Hg 0.1
± 10.18 inches Hg 0.01
± 34.47kPa 0.01
± 11.53feet H2O 0.01
± 138.3inches H2O 0.1
± 351.5cm H2O 0.1
± 80.00oz in20.01
Warning: Pressure inputs of 10 psi or higher will damage the instrument. Do not
apply pressure higher than the maximum pressure listed in the specification table
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Battery Replacement
When the low battery indicator BAT appears on the display or if the meter does not switch on
when the POWER button is pressed, it is necessary to replace the battery.
To replace the battery:
1. Open the battery compartment by sliding the  meter s rear panel in the direction of the
embossed arrow.
2. Replace the 9V alkaline battery
3. Replace the battery compartment cover.
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.
Conversions
Useful conversion Factors
From To Multiplier
in of H2O in of Hg 0.07355
in of H2O cm of H2O 2.54
mm of Hg in of H2O 0.03937
Copyright ©2013 2015 FLIR Systems, Inc.
All rights reserved including the right of reproduction in whole or in part in any form
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