Gardner Denver Welch Self-Cleaning Dry Vacuum System DryFast... User manual

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OWNER’S MANUAL
FOR
SELF-CLEANING DRY VACUUM SYSTEM™
MODELS: 2025, 2026, 2027 & 2028
Gardner Denver Welch Vacuum Technology
7301 North Central Avenue
Skokie, IL 60077
Phone: [phone]
Fax: [phone] (Technical Support)
Fax: [phone] (Ordering)
E-Mail: [email protected] Part No. 67-0790R2.1
Web-Page: www.welchvacuum.com Printed in USA
For outside of U.S. and Canada, contact your local
Gardner Denver sales office, see back page
Approval Agency’s
WARNING
Be sure to properly identify intake and discharge
before using pump. See Section 2.28.
CAUTION
Do not pump liquids with the pump.
Pumping liquids will cause the pump to stop working.
2025 2027 2028
(9 Torr, 12 mbar) (2 Torr, 2.7 mbar) (2 Torr, 2.7 mbar)
2026
(2 Torr, 2.7 mbar)
Improved to better meet your laboratory needs.
- New electronics with an enhanced self-cleaning
feature to help extend diaphragm life
- Superior vacuum level regulator for setting vacuum pressures
- Improved corrosion resistant housing and front panel
- Protective jar cover to help protect inlet and outlet jars
- Enhanced caring handles for better portability
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INSTRUCTION
WARNING AND CAUTION
PLEASE READ BEFORE OPERATION
While reading your manual, please pay close attention to areas labeled:
WARNING AND CAUTION.
The description of each is found below.
WARNING
Warnings are given where failure to observe instruction could result
in injury or death to people.
CAUTION
Cautions are found where failure to observe the instruction could result
in damage to the equipment, associated equipment and process.
These units confirm to the SI International system of units of measurement.
The following symbols (with recommendation of IEC1010 ) of warning will be found on the pump.
Caution - refer to accompanying documents
Caution - risk of electrical shock
Caution - hot surface
WARNING
Motor includes a self resetting thermal cutout and the pump could
restart without actuation under fault condition.
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TABLE OF CONTENTS
Section 01 - Safety Information
1.10 Caution to Prevent Injury
1.20 Caution to Reduce Risk of Electrical Shock
1.30 Warning to Reduce Risk of Electricution
1.40 Danger to Reduce Risk of Explosion or Fire
Section 02 - Installation
2.10 Intoduction
2.20 Electical Power
2.30 Traps
Section 03 - Operation
3.10 Starting Procedure
Section 04 - Maintenance
4.10 General Maintenance
Section 05 - Calibration
5.10 Calibration for Model 2027 only
Section 06 - Troubleshooting
6.10 Vacuum Problems
Section 07 - Specification
7.10 Pump Specification Table
Section 08 - Drawings, Parts List and Exploded View
8.10 Dimensional Drawing
8.11 Schematic Wiring Diagram for Models 2025 and 2026
8.12 Schematic Wiring Diagram for Model 2027
8.13 Parts List and Exploded View for Dry Vacuum System
8.14 Parts List and Exploded View for Repair Kits
Section 09 - Warranty
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Section 1: SAFETY INFORMATION
1.10 CAUTION: To prevent injury....
1.11 Never operate this product if it has a damaged cord or plug. If it is not working properly, has been
dropped, damaged or has fallen into water, please return the product to a Gardner Denver
Welch Vacuum Technology service center for examination and repair.
1.12 Keep the cord away from the heated surfaces.
1.13 Never block any air openings or place it on a soft surface where the openings may be blocked.
The air openings are for ventilation of the motor inside the housing. Keep all air openings free of lint,
dirt and other foreign objects.
1.14 The PTFE pump is thermally protected and can automatically restart when the protector resets.
Always disconnect power source before servicing.
1.15 Wear safety glasses or goggles when operating this product.
1.16 Use only in well ventilated areas. The motor is fan cooled enclosed in a shell.
WARNING
Do not operate the pumps in an atmosphere
containing flammable or explosive gases/vapors.
WARNING
Never block the exhaust port. If the exhaust is blocked, pressure
will build-up in the pump with the potential of the pump head
bursting and causing possible injury to personnel in the area.
1.17 All electrical products generate heat. To avoid serious burns never touch unit during or immediately
after operation.
1.18 Be sure to properly identify intake and discharge before using pump. See Section 2.14.
WARNING
Remove plug(s) from Exhaust Port(s). The Self cleaning Dry Vacuum
System has one outlet port and one inlet port. The ports are labeled.
1.20 CAUTION: To reduce risk of electrical shock....
1.21 Do not disassemble. Disassembly or attempted repairs if accomplished incorrectly can create
electrical shock hazard. Refer servicing to qualified service agencies only:
Contact your closest Gardner Denver Welch Vacuum Technology sales office. See directory on back cover.
1.22 Unit is supplied with a three pronged plug. Be sure to connect pump to a properly grounded
outlet only.
1.30 WARNING: To reduce risk of electricution…
1.31 Do not use this product in or near area where it can fall or be pulled into water or other liquids.
1.32 Do not reach for this product if it has fallen into liquid. Unplug immediately.
1.33 Never operate this product outdoors in the rain or in a wet area.
1.40 DANGER: To reduce risk of explosion or fire…
1.41 Do not use this pump near explosive atmospheres or where aerosol (spray) products are being used.
1.41 Do not use this product near flames.
WARNING
Failure to observe the above safety precautions could result
in severe bodily injury, including death in extreme cases.
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Section 2: INSTALLATION
2.10 Introduction
This manual has been compiled not only for the care and maintenance of the Welch Dry Vacuum System
now in your possession, but as a helpful reference and guide to prevent many problems which can occur
if used improperly.
2.11 Unpacking
Carefully remove the Dry Vacuum System from the shipping carton. Preserve all paperwork for future
reference. If damage has occurred from shipment a claim must be filed with the carrier immediately;
preserve the shipping carton for inspection by the carrier. If you are required to communicate with
your dealer or Gardner Denver Welch Vacuum Technology be sure to include your order numbers for
quick identification. Do not return the system to the factory without first calling for a returned goods number.
Contact your closest Gardner Denver Welch Vacuum Technology sales office. See directory on back cover.
2.12 System Mounting
Rubber feet are attached to the pump. Rubber feet are excellent for applications involving a
semi-flexible surface such as a bench top; they help to isolate noise and eliminate creeping.
The Self-Cleaning Dry Vacuum System must be positioned with the feet on a flat surface.
2.13 System Location
The Self-Cleaning Dry Vacuum System should be located preferably in a clean, dry and well ventilated
area. Please be sure not to block the ventilation ports located on the metal shell. The pump should be
placed where the surrounding temperature remains between 10°C and 40°C (50°F and 104°F). Always
check to insure the location chosen is protected from direct or indirect moisture contact. The pump
should be located as closely to its system in order to utilize it most efficiently.
WARNING
Don’t operate this pump in an atmosphere
containing flammable or explosive gases or vapors.
WARNING
The motor is thermally protected and will automatically
restart unexpectedly when the overload device resets.
2.14 Inlet and Outlet Provisions
An inlet hose barb which accepts ¼” (7mm) I.D. hose makes it easy to connect the system to your
concentrator, rotary evaporator or gel dryer. Since the vacuum system operates in the viscous flow
range, the small diameter of the hose will generate minimal conductance loss. For best results, Welch
recommends the length of the tubing between the pump and the apparatus be kept as short as possible.
Hose clamps should be used to hold the hose in place.
The hose barb in the outlet port of the pump accepts ¼” (7mm) I.D. hose. A vent line can be attached
to the outlet hose barb which allows gases and vapors pumped through the pump to be piped to a fume
hood. If you any questions, be sure to call technical service prior to start-up. Contact your closest
Gardner Denver Welch Vacuum Technology sales office. See directory on back cover.
WARNING
Never Block The Outer Port. If the outlet is blocked, pressure will
buildup in the pump which can lead to the pump head bursting
creating the potential of serious injury. Remove plug from outer port.
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PROPERLY IDENTIFY THE INLET AND OUTLET OF THE PUMP
Outlet Port
Inlet Port
WARNING:
(Model 2028 shown) Remove Plug From Exhaust
Port Before Operating.
2.20 Electrical Power
2.21 Power Source Review
Review the power source and the voltage rating on the units serial number tag to be sure they agree in
voltage, phase and frequency. Serious damage may occur to the system if it is connected to an improper
voltage. All Welch systems must be grounded. Grounding reduces the risk of electric shock in the
event of an electrical short circuit. The plug must be plugged into an outlet properly grounded.
Consult your local electrical codes if you have doubts.
2.22 Identification Symbols on Models: on Model:
2025,2026 & 2027 2028
2.23 Grounding Instructions
This product should be grounded. In the event of an electrical short circuit, grounding reduces the risk
of electric shock by providing an escape wire for the electric current. This product is equipped with a
cord having a grounding wire with a grounding plug. The plug must be plugged into an outlet that is
properly installed and grounded in accordance with all local codes and ordinances.
DANGER
Improper installation of the grounding plug
can result in a risk of electrical shock.
If repair or replacement of the cord or plug is necessary, do not connect the grounding wire to either flat blade
terminal. The wire with insulation having an outer surface that is green with or without yellow stripes is the
grounding wire.
Check with a qualified electrician or serviceman if the grounding instructions are not completely understood, or if
in doubt as to whether the product is properly grounded. Do not modify the plug provided; if it will not fit the
outlet, have the proper outlet installed by a qualified electrician.
Model’s 202501, 202601, 202701 and 202801 are for use on a nominal 120V circuit, and has a grounding plug
that looks like the plug illustrated in Sketch A in Figure #1. A temporary adapter, which looks like the adapter
illustrated in sketches B and C, may be used to connect this plug to a 2-pole receptacle as shown in sketch B if a
properly grounded outlet is not available.
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The temporary adapter should be used only until a properly grounded outlet (Sketch A) can be installed by a
qualified electrician. The green colored rigid ear, lug, etc. extending from the adapter must be connected to a
permanent ground such as a properly grounded outlet box cover. Whenever the adapter is used, it must be held in
place by a metal screw.
2.24 Extension Cords
If necessary to use an extension cord, use a 3-wire extension cord that has a 3-blade grounding plug, and a 3-slot
receptacle that will accept the plug on the product. Make certain your extension cord is in good condition. Make
certain your extension cord wire size is not less than 18 guage for 25 feet, 16 guage for 50 feet, and 14 guage for
100 feet. An undersized cord will cause a drop in line voltage resulting in loss of power and overheating. If in
doubt, use the next heavier cord. The smaller the guage number, the heavier the cord.
2.25 Vacuum Gauges
2.25.1 Analog Vacuum Gauge
A dial vacuum gauge is incorporated in the vacuum system 2025 and 2026.
The dial gauge is located in the top front section of the system.The dial vacuum gauge is commonly used to
indicate vacuum level when operating in the rough vacuum range (2 torr, 2.7mbar, 29.8 in Hg). Dial vacuum
gauges give negative pressure - that is pressure below atmospheric. The reference point for the gauges is
atmospheric pressure.
Please keep in mind that atmospheric pressure tends to vary from day to day. As a result of this variability, a
dial vacuum gauge will indicate slightly different maximum vacuum readings from day to day.
2.25.2 Digital Vacuum Gauge for 2027 only
A digital vacuum gauge is incorporated into the model 2027 vacuum system.
The digital gauge is an absolute gauge located in the top front section of the Self-Cleaning system. The unit of
measurement is preset during production.
To change the unit of measurement, unplug the pump, remove the base panel at the bottom of the pump and adjust
the unit of measurement switch (SW1) to the desired setting as indicated in the above table.
Diagram of Board and Switch SW1 is located in Section 6.11 and 6.12 .
Model Unit of Measurement On Switch Setting (SW1)
202701 Torr or
202703 mbar
202705 kPa
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8
2.25.3 Digital Vacuum Gauge for 2028 only
A digital vacuum gauge is incorporated into the model 2028 vacuum system.
The digital gauge is an absolute gauge located in the top front section of the Self-Cleaning system. The unit of
measurement is preset during production.
Set Units
- Allows the user to change vacuum units from torr, mbar, and kPa.
1) Press the MENU button on the front panel and use the vacuum control knob to scroll
to the “Setup” option # 3 and push in the Vacuum Control knob.
2) Scroll to “Set Units” option # 1 and push in the Vacuum Control knob.
3) Scroll to the desired units and push in the Vacuum Control knob. The * will appear
next to the selected and set units.
4) Push in the Vacuum Control knob to exit or scroll to “Back” to go back to the
previous screen.
5) The gauge will automatically display all values in the new unit of measurement.
2.26 Vacuum Level Regulation
Vacuum level regulation is accomplished with an adjustable bleed valve. The adjustable bleed valve allows close
control of pressure in your apparatus. Pressure may be set between roughly atmospheric pressure and the
maximum obtainable vacuum (2 torr, 2.7mbar, 29.8 in Hg).
2.27 Gas Ballast Valve (Models 2025, 2026 & 2027 only)
The gas ballast or vent switch acts to minimize vapor condensation when pumping heavy vapor loads.
In a pump functioning on an apparatus with a high vapor load, compression within the pump takes place in
the normal manner until the saturation pressure of gas and vapor is reached, causing the vapor to condense in the
pump mechanism. When air at atmospheric pressure is supplied to the compression stoke by means of the gas
ballast valve, the partial pressure of the unwanted vapor becomes a very small part of the total pressure of the
mixture of gas, vapor and newly supplied air. The vapor is then prevented from reaching its saturation pressure
corresponding to the temperature of the pump and is finally expelled from the pump as a vapor.
Models 2025, 2026 & 2027 have a toggle gas ballast valve incorporated in its design. By moving the
toggle switch to its upward position, the valve is opened. A fixed amount of air will then flow into the second
stage of the pump. Because of the increase in gas load, the pump’s ultimate pressure deteriorates slightly.
Prolonged operation of the pump with the gas ballast open is not injurious to the pump.
Vacuum Gauge Separator
Outlet
Inlet
Vacuum Level
Regulator
Gas Ballast Valve
Purge
Light (Self-Cleaning)
Power Switch
(Model 2027 shown. Models 2025 and 2026 come with a dial vacuum gauge)
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2.28 Inlet and Outlet Separators (all Models)
The glass inlet separator helps protect the diaphragm pump inside the system from ingesting liquids
or particulates.
The outlet separator catches any liquid or particulates ejected while the pump is running and when its is operating
in the self-cleaning purge cycle.
WARNING
Always wear safety gloves that are designed for handling glass when removing
the inlet or/and exhaust jars.
Cracked or defective jars can break when being removed.
2.29.1 Self-cleaning Purge (Models 2025, 2026 & 2027 only)
Failure of a diaphragm pump using fluorinated plastics commonly comes from the buildup of liquids or solid
residue over time on the diaphragm or internal valves. Any particulates, water or condensed vapor that may have
been ingested into the diaphragm pump, which is the heart of the Self-Cleaning Dry Vacuum System, is purged
when the system is turned off. The self-cleaning purge automatically turns on for approximately 2 minutes upon
turning off the pump. The digital display will count down in seconds the time left in the purge cycle.
During the last10 seconds of the purge cycle the pump will shut off allowing the unit to vent to atmospheric
pressure.
The outlet separator catches any liquid or particulates during the purge cycle.
To adjust the purge cycle time on Models 2025, 2026 & 2027 from 2 minutes to 2.5, 3.0, or 3.5 minutes, unplug
the pump, remove the base panel at the bottom of the pump and adjust the delay in minutes switch (SW2) to the
desired setting as indicated in table below.
Diagram of Board and Switch SW2 is located in Section 6.11 and 6.12 .
2.29.2 Self-cleaning Purge (Model 2028 only)
Set Cleaning Time
- Allows the end user to change the self-cleaning purge time from 2, 3 or 4 minutes.
1) Press the MENU button on the front panel and use the vacuum control knob to scroll
to the “Setup” option # 3 and push in the Vacuum Control knob.
2) Scroll to “Set Cleaning Time” option # 2 and push in the Vacuum Control knob.
3) Scroll to the desired time (2, 3 or 4 minutes) and push in the Vacuum Control knob.
The * will appear next to the selected and set time ( in seconds).
4) Push in the Vacuum Control knob to exit or scroll to “Back” to go back to the
previous screen.
5) The Self-Cleaning purge will automatically be changed to the new time.
9
Delay in Minutes (Seconds) On Switch Setting (SW2)
2.0 (120 sec)
2.5 (150 sec)
3.0 (180 sec)
3.5 (210 sec)
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2.30 Traps
2.31 When To Use A Trap
The Self-Cleaning Dry Vacuum System is constructed of PTFE or fluorinated plastics on all wetted surfaces to
resists chemical attack from aggressive solvent, base and acid vapors. A totally oil free diaphragm mechanism
removes the need for lubricating and sealing fluids for pulling a vacuum. When pumping gases or low vapor
loads, a trap is not necessary unless you want to capture vapors evolved from the process.
When a heavy load of water or organic vapor is evolved from the vacuum process, condensation of vapor in the
pump mechanism may occur. The reason is the pump is compressing the vapor as it passes through the pump. If
the vapor is dense enough, the compression will cause condensation of the vapor in the pump mechanism. The
valve system in the pump mechanism is designed to pass the small quantity of liquefied vapor formed when
pumping heavy vapor loads. The liquid formed will be ejected from the outlet port. The self-cleaning purge
feature of the Self-Cleaning Dry Vacuum System is designed to eject condensed vapors left in the pump upon
shut-done.
The advantage of a cold trap when pumping heavy vapor loads is that it will increase the effective pumping speed
of the Self-Cleaning Dry Vacuum System. The trap acts as an additional pumping mechanism, increasing the
effective pumping speed. This higher effective pumping speed will shorten the time needed to strip solvent. The
time savings will depend on such factors as the solvent stripped, solvent temperature and operating temperature of
the cold trap.
The cold trap is installed between the pump and the vacuum chamber. The water or organic vapors evolved from
the vacuum process entering the cold trap will come in contact with the cold surfaces of the trap and condense.
Commonly used refrigerants are liquid nitrogen or dry ice with alcohol slurry. Dry ice provides sufficient
cooling to freeze out most heavy water vapor loads. A variety of cold traps are available from Welch. Contact
your closest Gardner Denver Welch Vacuum Technology sales office. See country directory on back cover,
or visit the Welch Web-Site at www.welchvacuum.com.
2.32 The Care of a Liquid Trap
A liquid trap needs no refrigerant. The key maintenance issue when pumping high vapor loads is to regularly
drain the trap of liquid ejected from the dry vacuum pump.
2.33 The Care of a Cold Trap
When using a cold trap the refrigerant should be maintained at a high level in the flask to keep the trap at a
uniformly low temperature. If the trap is rewarmed it may allow re-evaporation of the condensate. If the trap
becomes saturated it should be disconnected from the system, drained and cleaned. An increase in pressure in the
vacuum system will normally indicate that the trap has become saturated. To clean the trap, remove the trap from
the system and allow the trap to warm up and rinse off the condensate with a suitable solvent in a fume hood.
Thoroughly clean and dry the trap before reinstalling the system.
If a liquid nitrogen trap is used, the refrigerant add tube on the liquid nitrogen trap should not be obstructed as the
refrigerant boil-off can produce dangerously high pressures.
2.34 Application Note for Cold Trap
Cold traps employing a dry ice slurry or liquid nitrogen are effective as long as the refrigerant level is maintained.
If the trap warms up while the pump is running, all of the traped condensables will be ingested by the vacuum
pump. Cold traps must be cleaned out at the end of each day. If the pump is run overnight, the trapped
condensables will ultimately be ingested by the pump as the trap warms up. Cleaning a Dry Ice Slurry/Liquid
Nitrogen trap is easy. The steps are:
1. Turn off the pump.
2. Leak air into the trap.
3. Remove the center well and plexiglas ring to a hood. The center well can be washed off into a
beaker or the condensables can be allowed to evaporate in the hood.
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Section 3: OPERATION
3.10 Starting Procedures
3.11 Starting a Welch Vacuum System
Before attaching the Self-Cleaning Dry Vacuum System to a rotary evaporator, concentrator or gel dryer it is
important to familiarize yourself with the function, features and action of the Self-Cleaning Dry Vacuum System
which you have acquired.
Review the power requirements as described in Section 2.20, Electrical Power
Welch recommends running the system for a few minutes to warm it up before use. The warm-up improves the
pumps ability to pass water and organic vapor. A warm pump will handle more vapor without liquefying it than a
cold pump.
3.12 Cleanliness
Take every precaution to prevent foreign particulates or liquid from entering the pump. Particulates or a flow of
liquid will damage the pumps performance. If you find that large quantities of particulates or liquid will come off
the process during evaculation, a simple liquid trap can be made out of readily available material for protecting
the pump. The trap would consist of a filtering flask placed between the pump and the vacuum chamber. The
simple liquid trap will act as a buffer for the inlet separator connected to the Self-Cleaning Dry Vacuum System.
3.13 Leak Detection
The importance of eliminating all leaks in a vacuum system is obvious. The pump must remove this added
volume of leaked gas to maintain the desired vacuum. Leaks in the application can be located by slightly
pressurizing the system and painting the suspected area with a thick soap solution. Escaping air will produce
soap bubbles.
3.14 Operating Pressure Range
The Self-Cleaning Dry Vacuum System is designed to be run from slightly below atmospheric to
2 Torr (2.7mbar, 29.8 in Hg). See Section 6, specification list for the complete specifications for your unit.
3.15 Operating Instruction for 2028
MANUAL VENT
AUTO Anti BUMPING/FOAMING
MENU MAXIMUM VACUUM
NUMERIC KEY PAD UP/DOWN ARROWS
VACUUM CONTROL
KNOB
Push to select menu options
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VENT MODE
Note: the gauge will not display atmospheric pressure.
The pump will automatically go into vent mode when the pump is turned on.
VENT Mode is the central mode to allow the user to enter MENU, AUTO, MANUAL
and MAXIMUM VACUUM modes. VENT mode allows the user to quickly remove the
vacuum setting on an application and vent the system.
All programs are quickly accessible in VENT mode by pressing the numeric keypad for each
program number.
Example:
Keypad # Program #
0 Repeat Previous Setting
1 1
2 2
3 3
4 4
5 5
Note: Press the ENTER button to run the selected program
MANUAL MODE
Press MANUAL button to enter MANUAL mode
MANUAL mode gives you full control of the vacuum setting by manually opening/closing the
variable valve with each turn of the Vacuum Control knob. The linear bar graph displays the valve
position. Push the Vacuum Control knob to lock in your desired vacuum setting and switch to
AUTO mode. AUTO mode will display the exact vacuum setting and allow you to use all AUTO
mode functions.
Note: MANUAL mode defaults to the valve open (vent) position when pressed except when in
MAXIMUM VACUUM mode where the valve will be in the closed (max vac) position.
AUTO MODE
Press AUTO button or Vacuum Control knob in MANUAL mode to enter AUTO mode
AUTO mode gives you precise control of the vacuum setting via Up/Down arrows, Numeric
Keypad and the Vacuum Control knob. The bottom right of the display shows the set vacuum
setting. The initial vacuum setting must be set via the numeric key pad and enter button. Once
the initial value has been entered the Up/Down arrows, Numeric Keypad and the Vacuum Control
knob will all allow precise vacuum control in AUTO mode. The only exception is when the users
switches from MANUAL mode to AUTO by pushing the Vacuum Control knob
(see MANUAL mode).
MAXIMUM VACUUM MODE
Press MAXIMUM VACUUM button to enter MAXIMUM VACUUM mode
MAXIMUM VACUUM mode closes the valve and sets the pump to the maximum vacuum level.
To adjust the vacuum level in MAXIMUM VACUUM mode you can press the MANUAL mode
button and use Vacuum Control knob to open/close the variable valve (see manual mode) or press
the Anti-BUMPING/FOAMING button to decrease the vacuum level by several torr.
Note: Selecting MANUAL mode while in MAXIMUM VACUUM sets the unit in MANUAL
mode with the valve in the closed (maximum vacuum) position.
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13
Anti-BUMPING/FOAMING MODE
The anti-BUMPING/FOAMING functions will decrease the set vacuum level by several torr.
Continual pressing of the Anti-BUMPING/FOAMING button will decrease the vacuum setting
an equally additional several torr, mbar or kPa.
The anti-BUMPING/FOAMING is only enabled in AUTO mode.
Press once and the vacuum decreases, press a second time and the unit goes
back to MAXIMUM VACUUM.
MENU MODE
Press MENU to access all program functions
1) Repeat
2) Program
3) Setup
4) About
5) Exit
Use the Vacuum Control knob to scroll through all the MENU options. Push the Vacuum Control
knob to select a highlighted MENU option
- 1) REPEAT
Repeat displays the previous run vacuum setting or program number. Use the Vacuum Control
knob to scroll to the Repeat option and press to repeat previous setting.
Note: The Repeat option is quickly accessible in VENT mode by pressing number “0”.
- 2) PROGRAM
Selecting the Program option allows the end user to select from one of five stored programs, enter
a new program or edit an existing one. Use the Vacuum Control knob to scroll to the Program
option and press to enter the Program menu screen.
The Program screen displays all existing stored programs in desired vacuum units and time
(minutes). Use the Vacuum Control knob to scroll up and down and press the Vacuum Control
knob to enter your selection.
If the memory location is empty the following screen will appear. Enter the values requested, first
vacuum setting (P1), first time setting in minutes (T1), second vacuum setting (P2), second time
setting in minutes (T2). If P1is entered and T1 is left blank the program will only store a vacuum
setting. If T1 and/or T2 is left blank, P2 will be set to run until unit is manually turned off.
If the values are entered correctly and have been saved, the program will redisplay the
entered values with the option to Edit, Run or Exit the program you just entered.
After each program ends with a timed value, the unit will automatically go into VENT, or
Self-Cleaning mode if Auto Shutdown is Enabled in Setup. ( see Setup)
If the memory location is full. The following screen will appear and request if you want to Edit,
Run or Exit the program. Use the Vacuum Control knob to select your option.
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All programs are quickly accessible in VENT mode by pressing the numeric keypad for each program number.
Example:
Keypad # Program #
1 1
2 2
3 3
4 4
5 5
Note: All pressure values will be entered according to the predefined unit settings
(torr, mbar, kPa). Time will be entered in minutes.
SETUP MODE
Press SETUP to access all program functions
1) Set Units
2) Set Cleaning Time
3) Auto Shutdown
4) Back
5) Exit
Use the Vacuum Control knob to scroll through all the MENU options. Push the Vacuum Control
knob to select a highlighted MENU option
- 1) SET UNITS
Use the Vacuum Control knob to select the Set Units option to change displayed units from torr,
mbar, and kPa. The Selecting Units screen will appear and display the current units setting with
an asterisk. Use the Vacuum Control knob to select the desired units and push the Vacuum
Control knob to change. The screen will now display the new vacuum units.
Use the Vacuum Control knob to select Exit or Back to make additional changes from the
Setup screen.
- 2) SET CLEANING TIME
Use the Vacuum Control knob to select the Set Cleaning Time option to change the Self-Cleaning
cycle time from 2, 3 or 4 minutes. The Select Clean Time screen will appear and display the
current setting with an asterisk. Use the Vacuum Control knob to select the desired time and push
the Vacuum Control knob to change. The screen will now display the new vacuum units.
Use the Vacuum Control knob to select Exit or Back to make additional changes from the
Setup screen.
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- 3) AUTO SHUTDOWN
Auto Shutdown mode allows the user to enable or disable shutting down the unit after a timed
program has run. When Auto Shutdown is Enabled the unit will automatically entered a timed
Self-Cleaning cycle after a time-entered program has completed. If Auto Shutdown has been
Disabled the unit will automatically go into vent mode and have to be manually turned off after a
time entered program has completed.
Note: The Self-Cleaning cycle is a key component of the Self-Cleaning pump and
cannot be disabled.
Use the Vacuum Control knob to select the Auto Shutdown option to Enable or Disable the Auto
Shutdown feature after a program has been completed. The Auto Shutdown screen will appear
and display the current setting with an asterisk. Use the Vacuum Control knob to select the
desired option and push the Vacuum Control knob to change. The screen will now display the
new setting.
Use the Vacuum Control knob to select Exit or Back to make additional changes from the
Setup screen.
- 4) ABOUT
Use the Vacuum Control knob to select the About option. The About option lists the product
model, version and contact information.
Section 4: MAINTENACE
4.10 General Maintenance
Welch dry vacuum units are 100% oil-free. The pump employs a diaphragm with uninterrupted Teflon® coating.
No maintenance is necessary for the bearings. All bearings are sealed and permanently lubricated. Lubrication
should not be attempted.
Welch’s Recommendation:
To extend the service life of the diaphragm membrane, turn off the Self-Cleaning Dry Vacuum System
when not in use. Running the system when not being used only creates wear on the flexing membrane in
the pump. When running the pump for several hours at a time in an application, Welch recommends air,
vapor or gas pass through the pump rather than run in a blank-off condition. The air, vapor or gas aid in
cooling of the pump mechanism extending the membrane’s service life.
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Section 5: CALIBRATION
5.10 Starting the Calibration for Model 2027 only
Under normal conditions the digital vacuum gauge on model 2027 vacuum system should not need recalibration
as it has been factory set. In the event that calibration is lost, the unit will flash the message:
“CAL Err” in the display. To recalibrate the unit an external vacuum gauge capable of measuring down to
2 Torr or less will be required.
Step 1: Unplug power from unit
Step 2: Turn unit over and remove the four phillips screws and the bottom cover.
Step 3: Locate the jumper (J11). See figure below
Remove the jumper and place over both pins. See figure “calibration mode” below
Step 4: Attach gauge to inlet of pump.
Step 5: Re-apply power to the unit.
CAUTION
Unit will start-up as soon as power is applied.
Display will flash: “ SEt CAL”.
WARNING
Unit is power be careful when removing calibration jumper ( Step 6)
Step 6: When external gauge shows 2 Torr or less, remove the jumper.
The unit will either go into purge cycle or normal operation, based on the position of the
ON/Off switch.
Step 7: Turn unit off and let purge cycle run to completion.
Remove power and install the jumper back to default setting, see figure “default setting” below.
Re-attache the bottom cover with four phillips screws.
default
setting
calibration
mode
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Section 6: TROUBLESHOOTING
6.10 Vacuum Problems
Leakage, contamination and unusual outgassing are the general causes of problems associated with poor vacuum.
To operate at maximum efficiency a system must be thoroughly clean. If the system is completely clean and free
from leaks, and unwarrantable vacuum problems still exist, the pump should be checked. A simple criterion for
checking the condition of the pump is the determination of its maximum vacuum capability. This can be
accomplished by blocking off the intake and reading the vacuum level on the gauge. (See Section 2.25)
17
Problem Possible Cause Solution
�Power off �Check all power connections
�Pump under Vacuum �Disconnect pump from system.
Open vacuum control valve and
Gas ballast.
Pump not working
�Self Diagnostic Test �Do nothing - the pump is running a
30sec. self diagnostic test to ensure
all components are working correctly.
If problem persists, contact Welch
Technical Support*.
�Open vacuum control valve and gas
ballast.
Pump stalled
�Pump under vacuum
Note:
Pump Cannot Start Under Vacuum
�Turn-off and UNPLUG PUMP,
remove top housing and turn fan a
few times. Replace cover and turn on,
if problem still persists contact Welch
Technical Support*.
Turn pump off, disconnect from
application, restart pump
�Check vacuum pressure of 2027xx with
external vac. gauge, attached to pump
inlet fitting.
�If external vac. gauge pressure is
different than unit's display by more
than 5 Torr, problem is with one of
three electronic parts (electronic
problems):
- Vac. pressure display
- Pressure pickup
- Electronic board
�Loose or not completely inserted wire or
connector
�All electronic connections on
electronic board and vac. display
should be rechecked to see that there
is no
�Multi wired pickup ribbon connection at
pressure pickup may have loose/broken
one of the four wires (usually one of
outside wires).
�New pickup should be installed or
repaired by re-soldering loose wire to
pressure pickup.
Electronic Failures
Display Shows unreliable measurements
�Electronic board could have corrupted
software or calibration
�Faulty board should be returned to
the factory to exchange it for new one
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Problem Possible Cause Solution
�External connection leak �Check and tighten all external tubing
connections; check tubing for cracks;
tighten connections in PTFE heads
�Gas Ballast is On �Switch Gas Ballast to OFF position
�Vacuum Control is not Closed �Closed Vacuum control (CW)
�Jar “Intake Side” is not tightened in place �Use Rubber Wrench to tighten jar
�Check vacuum pump pressure with external
vac. gauge, attached to pump inlet fitting
�If external vac. gauge pressure is the
same as unit's display, problem is with
faulty pump or external connection leaks
(mechanical problems)
�Solenoid valve is not operating properly �Valve is always in closed position except
purge cycle. Remove valve silencer and
plug valve inlet with rubber stopper. If
pressure drops it indicates leaky valve.
Insufficient Vacuum
�Internal leak �Bad valve or bad diaphragm; both bad
parts also effect noise; if there is no
vacuum, intake stage is problem.
�Vacuum level around 30-40 Torr
indicates bad exh. stage, valve or
diaphragm.
�Bad valve or diaphragm �Change Valve / Diaphragm
�Loose eccentric or counterweight �Tighten Loose Parts. Use Loctite
�Broken diaphragm threaded insert �Change Diaphragm
�Bad Con-Rod bearing or motor bearing �Change Con-Rod
�Broken motor shaft �Change Shaft
�Loose housing cover �Tighten housing screws on back of unit
Slide rail loose, remove housing cover
and slightly crimp slide rails on inner top
of housing cover. Do not over crimp.
�Loose inlet/outlet jars �Tighten jars
High noise
�Damaged diaphragm �Check vacuum performance - See Poor
Vacuum section below
If vacuum is still poor, contact
Welch Technical Support*.
�Loose motor mounting screws �Tighten screws
Excessive vibration
�Incorrectly installed counterweight or wrong
C'weight
�Failures described above also contribute to
excessive noise
�Adjust/reinstall/change C’weight
�Indicates partially plugged passage, usually
in exh. stage
�Clean/Unplug Stage
Mechanical Failures
Slow pump-down
�Plugged silencer �Unplug /change silencer
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Problem Possible Cause Solution
�Motor failure �Change Motor
seized pump
�Broken diaphragm – Con-rod connection �Change Diaphragm and/or Con-Rod
�Poor readings �See section 2.25.1 Analog Vacuum
Gauge
�Check vacuum performance - See
Poor Vacuum section above
Analog gauge
�Gauge not responding �Remove housing cover - check
connections and ensure hose is not
kinked. If hose is loose or kinked,
reattach or straighten.
�If problem persists, verify vacuum
with independent vacuum gauge. If
independent vacuum gauge reading
is still poor, Contact Welch Technical
Service.
�Poor readings �See section 2.25.2 Digital Vacuum
Gauge
�Check vacuum performance with
independent gauge - See Poor
Vacuum section above
�No display �Check power and power cord
�Turn pump off and UNPLUG PUMP,
wait 30 seconds, re-connect to power
and turn pump back on.
Digital gauge
�Displays "CAL Err" �Unit has detected a calibration error.
Mechanical Failures
Poor
Vacuum
�Leaks �Check inlet jar for leaks - Check inner
gasket and fittings, tighten if loose.
Disconnect pump from system, block off
inlet port, check vacuum level on the
gauge.
�If vacuum level reading is good, work
back through your application checking
for leaks.
�If vacuum level reading is still poor,
check vacuum control valve and gas
ballast to ensure they are completely
closed.
�If vacuum level reading is still poor,
disconnect pump from the application and
run the pump for 10 minutes with the
inlet port open, turn unit off and allow the
unit to complete purge cycle (clean).
Repeat and retest vacuum performance.
�If problem persists, contact Welch
Technical Support*.
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