L. J. ENGINEERING DVG User manual

Installation Instructions for All Model
Ranges of Digital Vacuum Gauge (DVG)
and Digital Pressure Gauge (DPG)
INSTALLATION NOTES:
1. Select the desired mounting location for the DVG or DPG. Keep in mind the length of the wall adapter power
cord and the location of the 120 Vac power outlet. The power outlet should be located in a dry location, away
from weather and areas where it could become wet. Enclosures of the Digital Gauges are water resistant, but
NOT WATERPROOF, therefore the mounting location should be as dry as possible. Use suitable screws or
bolts to fasten the Digital Gauge to the wall or mounting surface.
2. When the Digital Gauges are used to measure pressure or vacuum levels in systems which contain liquids,
care must be taken to ensure that liquid does not enter the gauge (hose barb). The mounting location and
installation arrangement must absolutely prevent liquid from entering the hose barb, since liquid inside the
gauge could damage the pressure/vacuum sensor. Install the gauge well above the liquid level of the system.
In addition, the use of an air-permeable/liquid-impermeable filter will ensure that no liquid enters the gauge.
GENERAL INFORMATION:
These instructions are intended to provide guidance on the installation, use, and trouble shooting for all ranges
of Digital Vacuum Gauges and Digital Pressure Gauges. A dash number located after DVG or DPG specifies
the range of the gauge. The gauge’s range and units of measure are shown directly below the digital display.
Verify that the pressure you intend to measure is within the range of the gauge. Pressure or vacuum in excess
of the gauge’s range could damage the unit. The Digital Gauge is designed for continuous monitoring with low
power consumption. It may be turned off by unplugging the wall transformer from the 120 Vac wall outlet. The
electrical connector at the DVG/DPG housing and power cord have gold-plated leads designed to provide long
life and protect from degradation due to corrosion.
L. J. Engineering
Document Number 10027
Revision A
Hose barb 0.155 in. dia. fits
0.125 in. inside dia. hose
Mounting hole
0.190 in. diameter
4.50 in. hole spacing
Power cord from
wall adapter
Optional analog
output

TROUBLESHOOTING:
If the Digital Gauge is not displaying numbers or decimal point, check to make sure that the wall adapter
is plugged into a wall outlet that has power. Additionally, verify that the power cord is properly attached
to the gauge connector.
If the gauge is suspected of incorrect pressure or vacuum indication, verify that it reads approximately
0 when no pressure or vacuum is applied. (Absolute Pressure Gauge models, however, should
indicate the approximate atmospheric pressure.) A small pressure or vacuum reading may be present
when no pressure or vacuum is applied to the system. This small variation is normal and occurs as the
meter is warming up after being turned on. Additionally, all meters are calibrated at the factory in a
vertical mounting position (e.g., mounting on a wall). Mounting the meter horizontally can have a slight
effect (plus or minus a few counts in the least significant digit) on the reading due to gravity acting on the
pressure sensor’s diaphragm. In any event, the meter should indicate the correct pressure or vacuum
within the accuracy tolerance of + 0.25% of the full-scale range once the meter has warmed up (approxi-
mately 15 minutes) and provided it is oriented in the vertical position, as calibrated at the factory.
If an air-permeable/liquid-impermeable filter is installed in the line, verify that it is not causing the read-
ing error by being plugged or contaminated. Indicated readings should be the same with and without
the filter installed. If the two readings are different, the filter is contaminated and requires replacement.
If repairs are necessary, please contact L.J. Engineering for assistance in returning the unit to the
factory for calibration/repair. A description of the problem should accompany the product being re-
turned. Disassembling any portion of the Digital Gauge housing or associated hardware is not
allowed under the warranty.
CLEANING:
UNPLUG THE WALL TRANSFORMER FROM THE 120 Vac OUTLET. Clean the outside of the case
with a damp cloth using a mild soap and water solution. Do not use solvents or chemicals to clean the
Digital Gauge since this could damage the case or label material.
3. Align the key of the plug on the connector-end of the wall adapter power cord with the mating
connector on the bottom side of the Digital Gauge. Push the black retaining collar up and rotate to lock
the connector together. Plug the transformer-end of the power cable assembly into a 120 Vac outlet and
the display will indicate a pressure or vacuum reading.
IMPORTANT!
If the Digital Gauge is equipped with an optional analog output, its lead wire assembly should be
isolated or unplugged from the Digital Gauge prior to plugging in the wall adapter to prevent the
leads from shorting to each other or any other electrical connection.
4. The Digital Gauge should provide many years of trouble-free operation provided that the gauge is
not subjected to abuse, such as liquids entering the barb or the application of pressure or vacuum in
excess of the gauge’s range.

SPECIFICATIONS:
Accuracy: +/- 0.25% of full scale range
Range: Specified on the front of each Digital Gauge below the digital display
Environmental Range:
Temperature: 0°F to 150°F
Relative Humidity: 95% non-condensing from 0°F to 150°F
Power Supply:
Input: 120 Vac, 60 Hz, 6 W
Output: 9 Vdc, 300 mA
Optional Analog Output:
An optional analog output is available which is proportional to the meter reading and ranges
over the full output voltage range of the pressure sensor (typically 0.25 Vdc to as much as 4.5
Vdc for the full range). A connector similar to the power cord connector, but with the reverse
plug configuration to prevent interchanging, is located at the bottom of the case. Polarity of the
analog cable is Red wire (+) and Black wire (-). Do not short these leads together or connect
either wire to a power source. Damage to the Digital Gauge will result.
LIMITED WARRANTY:
L. J. Engineering, Inc. (“LJE”) warrants to Buyer that the product here furnished is free of defects in material and workmanship for a period
of twelve (12) months from the date of delivery to the end-user customer. LJE’s sole obligation, and Buyer’s exclusive remedy for defects
in the product shall be limited, at LJE’s sole option, to either the repair or replacement of the defective product, or to issue a credit to
customer not to exceed the purchase price paid. The repair or replacement of the product under this warranty shall be FOB LJE’s plant,
Huntington Beach, California. Any claim by Buyer under this warranty must be made in writing not later than ten (10) days from the
discovery of the claimed defect, but in no event after the expiration of the above stated warranty period.
Products considered to be defective shall be returned to LJE, shipping costs prepaid, only after contacting LJE to coordinate the product
return. A description of the defect symptoms must accompany the returned product.
THIS WARRANTY IS THE SOLE WARRANTY COVERING THE PRODUCT AND LJE MAKES NO OTHER WARRANTY OF ANY KIND,
WHETHER EXPRESS, IMPLIED, OR STATUTORY. ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICU-
LAR PURPOSE ARE HEREBY DISCLAIMED AND EXCLUDED FROM THIS WARRANTY. IN NO EVENT SHALL LJE BE LIABLE FOR
SPECIAL, CONSEQUENTIAL OR INCIDENTAL DAMAGES ARISING FROM THE USE, STORAGE, OR PERFORMANCE OF THE PROD-
UCT, ANY DEFECTS IN THE PRODUCT, OR FROM LJE’S PERFORMANCE OF THE CONTRACT TO FURNISH THE PRODUCT.
This warranty shall not apply to product which has been repaired or altered other than by LJE; or to product which has been abused,
subjected to environments for which it was not designed such as fire, water, shock, or sand; or which was not installed, maintained, or
operated within its normal rated usage and the requirements set forth in the instruction material accompanying the product. If no such
instruction material accompanied the product, do not attempt to install or operate the product until you contact LJE for,
and receive, such instruction material and have read and understood it.
L. J. ENGINEERING, INC.
18192 Gothard Street
Huntington Beach, CA 92648 USA
Phone: [phone]
Fax: [phone]