USER GUIDE
Heavy Duty
Differential Pressure Manometer
Model HD750
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 (www.extech.com) 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 button – Press to switch the display backlight ON.
The backlight will automatically turn OFF after 40 seconds.
11. POWER button – Press to turn the meter ON or OFF
12. Battery compartment (on rear)
2 HD750-en-GB_V1.8 4/15
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
3 HD750-en-GB_V1.8 4/15
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
Pounds per square inch
Display icon psi
Inches of Mercury
Milli‐bar
Millimeters of Mercury
Kilo‐Pascals
Kilograms per centimeter squared
Inches of water inHg mbar mmHg kPa
Kgcm
2
Feet of water
Centimeters of water
Bars
Ounces per square inch inH
2
O ftH
2
O cmH
2
O
Bar ozin
2
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.
4 HD750-en-GB_V1.8 4/15
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
5 HD750-en-GB_V1.8 4/15
Specifications
General Specifications
Display
Units of Measure
Accuracy
Repeatability
Linearity/Hysteresis
Combined Accuracy
Maximum Pressure
Response time
Input circuit
Input Ports
Data Hold
Sensor
Zero / Offset function
Sample rate
Compatibility
Auto Power OFF
PC Interface
Storage conditions
Operating conditions
Battery power
Battery life
Dimensions
Weight
Four digit LCD with function indicators
BAR, mBAR, psi, kg/cm
2
H
2
O, cm H
2
O, and oz in
2
, mm Hg, inches Hg, kPa, feet H
2
O, inches
±0.3%FS (@ 25°C)
±0.2% to 0.5% FS
±0.3%FS
±1.1%FS
10psi
0.5s typical
Differential inputs (P1 and P2)
Two metal 4.8mm, barbed for 1/8" (3.17mm) ID tubing
Freezes displayed reading
Built‐in piezoelectric sensors
Pushbutton activation
0.5 sec. (approx.)
Air or non‐corrosive and non‐ionized gas (not intended for use with liquids)
Meter turns off after approx. 20 minutes to conserve energy (can be deactivated)
Built‐in USB serial interface
0 to 60 o
C (14 to 140 o
F); < 80% RH
0 to 50 o
C (32 to 122 o
F); < 80% RH
9V alkaline battery (BAT low battery indicator)
125 hours typical
210 x 75 x 50mm (8.2 x 2.9 x 1.9”)
280g (9.8oz)
6 HD750-en-GB_V1.8 4/15
Range Specifications
Range/Units (Max.)
± 0.344bar
± 344.7mbar
± 5.000psi
± 0.351Kg/cm
2
± 258.5 mm Hg
± 10.18 inches Hg
± 34.47kPa
± 11.53feet H
2
O
± 138.3inches H
2
O
± 351.5cm H
2
O
± 80.00oz in
2
Resolution
0.001
0.1
0.001
0.001
0.1
0.01
0.01
0.01
0.1
0.1
0.01
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
7 HD750-en-GB_V1.8 4/15
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 o Never dispose of batteries in a fire. Batteries may explode or leak. o Never mix battery types. Always install new batteries of the same type.
Conversions
Useful conversion Factors
From in of H
2
O in of H
2
O mm of Hg
To in of Hg cm of H
2
O in of H
2
O
Multiplier
0.07355
2.54
0.03937
Copyright © 2013‐2015 FLIR Systems, Inc.
All rights reserved including the right of reproduction in whole or in part in any form
ISO‐9001 Certified
www.extech.com
8 HD750-en-GB_V1.8 4/15
