User’s Guide
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DVG60
Electronic Vacuum Gauge
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It is the policy of OMEGA to comply with all worldwide safety and EMC/EMI regulations that
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Directives. OMEGA will add the CE mark to every appropriate device upon certification.
The information contained in this document is believed to be correct, but OMEGA Engineering, Inc. accepts
no liability for any errors it contains, and reserves the right to alter specifications without notice.
WARNING: These products are not designed for use in, and should not be used for, patient-connected applications.
WARRANTY/DISCLAIMER
OMEGA ENGINEERING, INC. warrants this unit to be free of defects in materials and workmanship for a
period of 13 months from date of purchase. OMEGA’s WARRANTY adds an additional one (1) month
grace period to the normal one (1) year product warranty to cover handling and shipping time. This
ensures that OMEGA’s customers receive maximum coverage on each product.
If the unit malfunctions, it must be returned to the factory for evaluation. OMEGA’s Customer Service
Department will issue an Authorized Return (AR) number immediately upon phone or written request.
Upon examination by OMEGA, if the unit is found to be defective, it will be repaired or replaced at no
charge. OMEGA’s WARRANTY does not apply to defects resulting from any action of the purchaser,
including but not limited to mishandling, improper interfacing, operation outside of design limits,
improper repair, or unauthorized modification. This WARRANTY is VOID if the unit shows evidence of
having been tampered with or shows evidence of having been damaged as a result of excessive corrosion;
or current, heat, moisture or vibration; improper specification; misapplication; misuse or other operating
conditions outside of OMEGA’s control. Components which wear are not warranted, including but not
limited to contact points, fuses, and triacs.
OMEGA is pleased to offer suggestions on the use of its various products. However,
OMEGA neither assumes responsibility for any omissions or errors nor assumes liability for any
damages that result from the use of its products in accordance with information provided by
OMEGA, either verbal or written. OMEGA warrants only that the parts manufactured by it will be
as specified and free of defects. OMEGA MAKES NO OTHER WARRANTIES OR
REPRESENTATIONS OF ANY KIND WHATSOEVER, EXPRESS OR IMPLIED, EXCEPT THAT OF TITLE,
AND ALL IMPLIED WARRANTIES INCLUDING ANY WARRANTY OF MERCHANTABILITY AND
FITNESS FOR A PARTICULAR PURPOSE ARE HEREBY DISCLAIMED. LIMITATION OF
LIABILITY: The remedies of purchaser set forth herein are exclusive, and the total liability of
OMEGA with respect to this order, whether based on contract, warranty, negligence,
indemnification, strict liability or otherwise, shall not exceed the purchase price of the
component upon which liability is based. In no event shall OMEGA be liable for
consequential, incidental or special damages.
CONDITIONS: Equipment sold by OMEGA is not intended to be used, nor shall it be used: (1) as a “Basic
Component” under 10 CFR 21 (NRC), used in or with any nuclear installation or activity; or (2) in medical
applications or used on humans. Should any Product(s) be used in or with any nuclear installation or
activity, medical application, used on humans, or misused in any way, OMEGA assumes no responsibility
as set forth in our basic WARRANTY/ DISCLAIMER language, and, additionally, purchaser will indemnify
OMEGA and hold OMEGA harmless from any liability or damage whatsoever arising out of the use of the
Product(s) in such a manner.
RETURN REQUESTS/INQUIRIES
Direct all warranty and repair requests/inquiries to the OMEGA Customer Service Department. BEFORE
RETURNING ANY PRODUCT(S) TO OMEGA, PURCHASER MUST OBTAIN AN AUTHORIZED RETURN
(AR) NUMBER FROM OMEGA’S CUSTOMER SERVICE DEPARTMENT (IN ORDER TO AVOID
PROCESSING DELAYS). The assigned AR number should then be marked on the outside of the return
package and on any correspondence.
The purchaser is responsible for shipping charges, freight, insurance and proper packaging to prevent
breakage in transit.
FOR WARRANTY RETURNS, please have the
following information available BEFORE
contacting OMEGA:
1. Purchase Order number under which the product
was PURCHASED,
2. Model and serial number of the product under
warranty, and
3. Repair instructions and/or specific problems
relative to the product.
FOR NON-WARRANTY REPAIRS, consult OMEGA
for current repair charges. Have the following
information available BEFORE contacting OMEGA:
1. Purchase Order number to cover the COST
of the repair,
2. Model and serial number of the product, and
3. Repair instructions and/or specific problems
relative to the product.
OMEGA’s policy is to make running changes, not model changes, whenever an improvement is possible. This affords
our customers the latest in technology and engineering.
OMEGA is a registered trademark of OMEGA ENGINEERING, INC.
© Copyright 2002 OMEGA ENGINEERING, INC. All rights reserved. This document may not be copied, photocopied,
reproduced, translated, or reduced to any electronic medium or machine-readable form, in whole or in part, without the
prior written consent of OMEGA ENGINEERING, INC.
Thank you for purchasing our DVG60 Vacuum Gauge. It is an accurate instrument with original features. Please read these instructions
carefully to get the best performance and many years of trouble-free service from your DVG60.
OPERATING CONTROLS AND FUNCTIONS
1. ON-OFF slide switch.
2. Dual purpose LED indicator.
A. Illuminates when slide switch is ON.
B. Hardly glows, or may not Illuminate when battery is low.
3. LED lamps indicate the entire range for vacuum pump from
atmosphere down to 50 microns vacuum.
4. Tough high impact case.
5. Standard 1/4 inch male flare fitting.
6. Quick cap for fitting.
7. Built-in hanger.
8. Tilt up cover for battery compartment.
9. Compartment for 9 volt battery.
10. Calibration screw.
HOW TO USE DVG60 ON REFRIGERATION SYSTEMS
The purpose of this introduction is to aid the service engineer in evacuating any system by the most efficient method. The capacity of a
vacuum pump is defined by how fast the pump can evacuate a system; and the efficiency of the pump is defined by how deep a
vacuum it is capable of pumping over a length of time. The level of vacuum you want to achieve can only be determined by a vacuum
gauge.
Most service engineers who are experienced in evacuating systems know beforehand the approximate time the vacuum pump will
have to run. However, the only proof he has that the system is actually empty is by the reading of a vacuum gauge.
We have researched the numerous arrangements of using shut off valves and have found the subsequent valve layout to be the most
versatile and efficient. (Fig.2)
The following recommendations will help you pull a vacuum in the shortest
possible time:
1. The valves and connecting tubes (Fig.2) that are in-line from the refrigerating
unit to the pump should be of the same ID (size and type) as the original fitting
on the suction side of the pump.
2. Always pull a vacuum simultaneously from the high and low side of the system.
3. If you must connect your hose to an access fitting on the system, first remove
the core.
4. Use the shortest possible length of hose.
Oil vapors from a vacuum pump will contaminate all electronic vacuum gauges.
Oil vapors are produced after the running pump has stopped. The air at
atmospheric pressure rushes into the vacuum side of the pump causing an oil
turbulence. Most pumps are equipped with a check valve, but it only takes a tiny
amount of vapor to affect the electronic sensor. The following simple precautions
will assure you of many years of trouble free service. Referring to (Fig.2):
Before you stop the vacuum pump.
1. Close the pump valve first. 2. Close the vacuum gauge valve.
Before you start the vacuum pump.
1. Close all valves. 2. Start the pump. 3. Open pump valve. 4. Gradually open main valve, wait 5 seconds before opening gauge
valve.
MAINTENANCE
The DVG60 electronic vacuum gauge sensor is cleanable. It is good maintenance practice to clean the sensor periodically. Use an
eyedropper to pour about 2 teaspoons of ordinary rubbing alcohol into the fitting. Cap the fitting and shake about 10 seconds; empty
and air dry. (The slight movement of the fitting in the case is normal and does not affect the internal connection in any way.)
When transporting the DVG60 as a separate unit, close both ends with the quick caps.
EVACUATING A REFRIGERATION SYSTEM
Emptying a system of all its vapors, including moisture, is a matter of time, and the length of time depends upon:
1. Size of the vacuum pump. 2. Efficiency of the pump. 3. The size of the system. 4. The distance of the furthest part of the system to
the pump.
The most common time destroyer is an inefficient vacuum pump or a leak in the system that is discovered after an hour of pump
running time. To prevent both from happening, test for leaks before you start the vacuum pump by closing all the valves except for the
pressurizing valve. When you've completed the leak test and you are removing the test pressure gas, you can test the pump for
efficiency by leaving the main valve closed and opening the pump and vacuum gauge valve. This is called a blank-off test. The vacuum
gauge shows the lowest possible vacuum the pump is capable of pulling. This one time blank-off test does not guarantee that the pump
will be that efficient after it gets hot from running more than 15 minutes. There are many instances where the oil in the pump should be
changed, and it becomes obvious only when the pump is running hot.
If you estimate, for example, that the vacuum pump should evacuate the system in about 1 hour, it would be a smart plan to
periodically check the pump for efficiency. It only takes a few seconds. After the blank-off test, close the pump valve and open the main
valve. The reading on the DVG60 tells you the vacuum level the system is at. Each time you test the system for its vacuum level, there
should be a progressive reduction in the micron level. If the reading remains at the approximately 1,000 micron level, there is either
some gas pockets that are being drawn from the oil in the system or moisture in the system. In either case, if you know that the
compressor is efficient and there aren't any leaks in the system, it is going to be a matter of time to evacuate down to your target level.
HOW LOW A VACUUM SHOULD YOU PULL ON A SYSTEM?
Ever since vacuum pumps have been used in ON-SITE situations, the low pressure figure has been a judgement call with the
individual service engineer and contractor's policy. At some educational seminars, caution was expressed on going below 300 microns
because the compressor oil would be evaporated. Oil companies, who supply the industry with compressor oil, have discounted this
theory. After interviewing many experienced service engineers we have found that the average low pressure target most service
engineers look for on large systems is about 700 microns and on small systems about 400 microns.
CALIBRATIONS
The micron pressure readings have been calibrated at the factory. It is permanent and never needs re-setting. However, due to
seasonal temperature variations, you may have to make a slight ambient adjustment. The gauge is perfectly calibrated when, after you
push the slide switch to ON, both the atmosphere and slide switch lamps are energized. Should the 5,000 micron lamp go on instead of
the atmosphere lamp, insert a small screw driver into the opening at the side of the case (No. 10 in Fig.1), locate screw and make the
adjustment until only the atmosphere and slide switch lamps go on. Do not overturn the screw, it may turn off the atmosphere lamp.
OPERATION
WHEN CONNECTING HOSES TO THE DVG60, DO NOT USE WRENCHES OF ANY KIND. USE ONLY SERVICE HOSE
CONNECTIONS WITH A KNURLED FTTTING ON THE END. THE HAND TIGHT CONNECTION OF A SERVICE HOSE IS AN
ADEQUATE CONNECTION.
After you have connected the vacuum pump to the system, close all valves.
1. Run vacuum pump. 2. Gradually open main valve and pump valve. 3. Open valve to vacuum gauge. 4. Allow 15 seconds for
sensor to stabilize. During the initial stages of evacuation, the atmosphere lamp may go out. This is normal when large volumes of air
pass by the sensor. As the lamps indicate the vacuum levels in the system, 2 lamps may be energized at the same time. This is normal
when there is a transition from one range to the next.
LOW BATTERY INDICATION
If the LED indicator (No. 2, Fig.1) is not as bright as the other lamps, or it doesn't light at all, the battery should be changed.(Use only
Alkaline batteries.)
REMINDER:ALWAYS SHUT OFF THE GAUGE VALVE BEFORE YOU STOP THE VACUUM PUMP.
SPECIFICATIONS:
SENSOR TYPE . . . . . . . . . . .Thermistor
VACUUM RANGE . . . . . . . . .5000 Microns
SCALE INDICATORS . . . . . .LED
POWER SOURCE . . . . . . . .9 Volt Alkaline Battery (Not included )
CONTINUOUS USAGE . . . . .20 Hours (With a new battery)
LOW BATTERY INDICATOR . . . LED
DIMENSIONS . . . . . . . . . . . . . . . 1-1/2" X 1-3/4" x 5-3/4"
WEIGHT . . . . . . . . . . . . . . . . . . . 6-1/2 Oz.
120 VAC ADAPTOR . . . . . . . . . . Optional,
Order as Part No. DPG-T
DVG60 TROUBLESHOOTING GUIDE
ALWAYS MAKE SURE THERE IS NO LEAK IN THE SYSTEM BEFORE YOU START TO PULL A VACUUM
PROBLEM...ERRATIC READINGS
SOLUTION...The sensor is contaminated with oil vapor. Clean the sensor as described in the Maintenance section.
PROBLEM...ATMOSPHERE LED IS DIM OR DOESN'T LIGHT.
SOLUTION...Weak batteries. Replace wlth new Alkaline batteries only.
PROBLEM...5,000 Micron LED LIGHTS INSTEAD OF ATMOSPHERE LED.
SOLUTION…Possible cause is excessive seasonal ambient temperature change. Make calibration adjustment as described in
Calibration section.
PROBLEM…AFTER UNIT HAS BEEN RUNNING AT 1,000 MICRONS YOU SHUT OFF THE PUMP VALVE, DVG60 RISES FAST TO
1,500 MICRONS.
SOLUTION...The vacuum at the gauge is 1,000 but the system is still 1,500 microns. This is a normal condition where there is a small
diameter tube between the vacuum pump and the system causing the pressure drop. As you continue to run the pump and the vacuum
level goes to 700 or less, the pressure difference will decrease. The best solution will be to use a very short length of tube with the
same ID as the fitting on the vacuum pump.
PROBLEM...AFTER THE UNIT IS RUNNING AT ABOUT 1,000 MICRONS, YOU SHUT OFF THE PUMP VALVE. THE READING OF
THE DVG60 RISES SLOWLY TO 1,500 MICRONS OR MORE.
SOLUTION...There is still more refrigerant or moisture in the system. Continue to pump down to the recommended level.
COMMONLY ASKED QUESTIONS
QUESTION...WHEN CONNECTING THE DVG60 TO THE SYSTEM, SHOULD I USE AN AUXILLARY FITTING ON MY VACUUM
PUMP OR USE A SERIES (IN-LINE) HOSE CONNECTION TO BOTH SIDES OF THE DVG60?
ANSWER...Do not use the DVG60 as a series connection from the vacuum pump to the system. This will definitely cause a pressure
drop. Most vacuum pumps have a fitting near the suction inlet of the pump. If you use this fitting for the DVG60 there is no way to shut
off the pump to see if there is a rise of vacuum in the system. Refer to Fig. 2.
OUESTION...IF I PULL A VACUUM TO 1,000 MICRONS AND CLOSE ALL THE VALVES, AFTER 10 MINUTES I THEN CHECK THE
SYSTEM AGAIN. IF THE READING DID NOT CHANGE, DOESN'T THAT PROVE THAT THERE ISN'T ANY LEAKS IN THE SYSTEM?
ANSWER...No, running under high pressure, refrigeration systems may have leaks which are nearly impossible to detect under
vacuum or low pressure conditions. The system should be tested for leaks by pressuring rather than by applying vacuum.
Whenever you close the valve at the vacuum pump and you notice a slow rise in the DVG60 reading, it simply means that there is
still some moisture or other vapors in the system. This condition makes it very important to check for leaks BEFORE you start to
evacuate the system and eliminate all doubts of possible leaks.
Where Do I Find Everything I Need for
Process Measurement and Control?
OMEGA…Of Course!
Shop online at www.omega.com
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