Gardner Denver Welch 2090W-01 User manual

OWNER’S MANUAL FOR DRY
VACUUM PUMPS
MODELS 2090W-01 and 2085W-01
Part No. 642978
Printed in the U.S.A.
WARNING
Be sure to properly identify intake and discharge
before using pump. See Section 2.5.

2
TABLE OF CONTENTS
SECTION PAGE
1.
Safety Information
3
2.
Installation
5
3.
Operation
8
4.
Maintenance
8
5.
Troubleshooting
9
6.
Specifications
10
7.
DimensionalDrawing
11
8.
ExplodedViews and Kits
12/13
9.
Warranty
14

3
Section 1: SAFETY INFORMATION
Read and understand the following information and instructions included with your Welch Dry
Vacuum Pumps before using. This information is for your safety and to prevent damage to the
pumps.
1.1 CAUTION: To Prevent Injury...
1.1a Never operate this product if it is not working properly, has been dropped, damaged or has fallen into water,
please return the product to a Welch service center for examination and repair.
1.1b Keep the cord away from heated surfaces.
1.1c 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.
1.1d Never drop or insert fingers or any other object into any openings.
1.1e This pump is thermally protected and can automatically restart when the protector resets. Always disconnect
power source before servicing.
1.1f Wear safety glasses or goggles when operating this product.
1.1g Use only in well ventilated areas.
1.1h All electrical products generate heat. To avoid serious burns never touch unit during or immediately after
operation.
1.1i Be sure to properly identify intake and discharge before using pump. See Section 2.5.
1.2 CAUTION: To Reduce Risk Of Electrical Shock...
1.2a Do not disassemble. Disassembly or attempted repairs if accomplished incorrectly can create electrical
shock hazard. Refer servicing to qualified service agencies only.
1.2B Be sure to connect pump to a properly grounded outlet only.
1.3 WARNING: To Reduce Risk Of Electrocution...
I.3a Do not use this product in or near area where it can fall or be pulled into water or other liquids.
1.3b Do not reach for this product if it has fallen into liquid. De-energize immediately.

4
1.3c Never operate this product outdoors in the rain or in a wet area.
WARNING
Failure to observe the above safety precautions could result
in severe bodily injury, including death in extreme cases.

5
Section 2: INSTALLATION
2.1 Introduction
This manual has been compiled not only for the care and maintenance of the Welch Dry Vacuum pump now in
your possession, but as a helpful reference and guide to prevent many problems which can occur if used
improperly.
2.2 Unpacking
Carefully remove the Dry Vacuum pump from the shipping case and unfasten and remove the wooden skid.
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 Welch Vacuum be sure to include your order numbers for quick identification.
Do not return the pump to the factory without first calling for a returned goods number.
2.3 Pump Mounting
Rubber feet are attached to the pump. Rubber feet are excellent for applications involving a semi-flexible surface
such as bench tops; they help to isolate noise and eliminate creeping. T he 2 090 / 2 08 5 vacuum pumps should
be mounted in a horizontal plane.
2.4 Pump Location
The pressure/vacuum pump should be located preferably in a clean, dry and well ventilated area. Please be sure
not to block the ventilation ports located on the motor housing. The pump should be placed where the surrounding
temperature remains between 10oC and 40oC (50oF and 104oF). Always check to insure the location chose is
protected from direct or indirect moisture contact. Welch recommends that the pump be installed at the highest
point within the system to prevent possible water condensate from entering the pump. The pump should be
located as closely to its system in order to utilize it most efficiently.
2.5 Intake and Discharge Provisions
The intake/exhaust connections are NW25 ISO vacuum flange with a 3/8"-18 NPT threaded I.D.
WARNING
The motor is thermally protected and will automatically restart
unexpectedly when the overload device resets.
WARNING
BurstingHazard–Partsforuseonexhaustportshouldbesuitable
forpressuresnotlessthan100PSIG.

6
2.6 Electrical Power
2.6a Power Source Review
Review the power source and the motor rating to be sure they agree in voltage, phase and frequency. Serious
damage may occur to the motor if it is connected to an improper voltage. All Welch pumps must be grounded.
Grounding reduces the risk of electric shock in the event of an electrical short circuit. Consult your local electrical
codes if you have doubts.
2.6b Overload Protection.
Motor thermal overload protection is made available by the motor manufacturer as an aid to minimizing motor
failure. Overload protection is a standard feature on both 50 and 60 Hz single-phase motors. The motors have
automatic overload protection. Automatic reset protection is designed to rest itself after a predetermined cooling
period. If the fault to the drive remains unaltered, the motor will cycle on and off until the fault is corrected.
2.7 Vacuum Connections
The 2090/2085 vacuum pumps come with NW25 ISO vacuum flange with a 3/8"-18 NPT threaded I.D. Hinge
clamps and centering assemblies should be implemented if using the flange connections. If using the 3/8”-18 NPT
threaded connection, a suitable quality liquid/paste thread sealant should be used. Since both models operate in
the viscous flow regime, 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 process be kept as short as possible. The
exhaust plumbing will act to muffle pump noise. The exhaust vent line will allow gases and vapors pumped
through the pump to be piped from the work area into a hood. Be sure to safely exhaust the process vapors with
consideration to worker health and fire safety.
2.8 Traps
2.8a The need for a Trap
The use of Teflon coated aluminum heads, Teflon liner over diaphragms and stainless valves allows the pumps to
handle mildly corrosive solvents, acids and bases. If there is a chance liquid may be drawn from the process
under evacuation, Welch recommends a liquid trap be placed between the process and the pump.
When a heavy load of vapor is evolved from the vacuum process, a cold trap is recommended to help prevent
damage to the pump mechanism.
The symptom of a high vapor load is if you have droplets of liquid coming out of the exhaust port. If you see
droplets of water, Welch recommends you use a cold trap to capture the water before entering the pump or dilute
the water vapor stream by adding dry nitrogen to the gas flow. Please call our customer service department for
additional information at [phone].

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2.8b The Care of a Trap
When using a cold trap the refrigerant should be maintained at a high level in order 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 into the system.

8
Section 3: OPERATION
3.1 Starting Procedures
3.1a Starting a Welch Dry Vacuum Pump.
Before attaching the pump to a system it is well to familiarize yourself with the function and action of the
pressure vacuum pump which you have acquired. Review the power requirements as described in Section 2.6.
Welch recommends running the pump for a few minutes to warm it up before use. The warm-up improves the
pumps ability to handle humid air.
3.1b Cleanliness
Take every precaution to prevent foreign particulates from entering the pump. Particulates will damage the
pump’s performance. If you find that particulates will come off the process during evacuation, a particulate trap
in the foreline will work.
3.2 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 for these pump can be located by slightly pressuring
the system and painting the suspected area with a water / liquid dish soap solution. Escaping air will produce
soap bubbles.
3.3 Operating Pressure Range
Models 2090 and 2085 Dry vacuum pumps are designed to be run from atmospheric to their maximum vacuum
level on the intake side. Consult the Specification Table in the back of this manual for the ratings for your
specific model.
3.4 Shutdown Procedures
After use, Welch recommends the pump be run for about 2 minutes disconnected from the vacuum process with
air or dry nitrogen passing through the pump. The air or dry nitrogen pumped through the mechanism will purge
out water vapor or droplets of water condensate that may have formed on the inside of the pump. Purging of the
pump mechanism helps prevent corrosion.
Section 4: MAINTENANCE
Welch dry diaphragm vacuum pumps are 100% oil-free. No maintenance is necessary for the bearings. All
bearings are sealed and permanently lubricated. Lubrication should not be attempted.
WARNING
The pump is not recommended for pumping highly corrosive acid or
base vapors or gases. Serious damage to the pump will result
and will shorten the pump’s service life.

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Section 5: TROUBLESHOOTING
5.1 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 unwarranted vacuum problems still exist, the pump should be checked. A simple criterion for the
condition of the pump is the determination of its maximum vacuum capability. This can be accomplished by
blocking of the intake and reading the vacuum level on the gauge (See Section 2.8).
5.2 Troubleshooting Guide
Poor Pumping
Speed
X
Poor
Vacuum
X
Loud Unit
X
Possible Cause
Damaged Valves
Corrective Action
Replace flapper valves
X
X
X
Debris in Valves
Remove debris and check
X
X
X
X
X
X
X
X
Damaged Gaskets
Loose Head Screws
Loose fittings
for valve damage
Replace gaskets
Tighten head screws
Tighten fittings
Others Symptoms:
1. Pump does not turn on - Cause: Inlet under vacuum - Corrective Action: Release vacuum at inlet.
2. Pump rocks when turned off - Cause: Inlet under vacuum - Corrective Action: Release vacuum at inlet prior
to turning off the pump.

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Section 6: SPECIFICATIONS
Welch Model
2090
2085
Free Air Displacement
CFM (L/min)@60Hz
4.5 (127)
6.9 (176)
Ult. Press., Torr (mbar)
25 (33)
100 (133)
Max Vacuum, in. Hg
29
26
Number of Vacuum Stages
2
1
Motor Horsepower
1/2
1/2
Vacuum Restart
yes
yes
Minimum Tubing Needed, I.D. in.
7/16
7/16
Weight, lbs. (kg)
52 (23.6)
52 (23.6)
Catalog Number
2090W-01
2085W-01
Motor Voltage
115V / 208-230V / 1PH / 60HZ
Motor Amps
9.8 / 4.9-4.9
Motor Hazardous Classification
CLASS 1 DIV 1 GROUP C,D
CLASS 2 DIV 1 GROUP E,F,G

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Section 7: DRAWINGS
7.1 Dimensional Drawings

12
Exploded View for 2085W-01
Parts List for
2085W-01
Item
No.
Part No.
Description
Diaphragm
Service Kit
2090K-01
Valve Plate
Service Kit
2090K-0 2
13
See Note 1
Valve Keeper
-
2
14
See Note 1
Screw-Valve Flapper-Intake
-
4
15
See Note 1
Screw-Valve Plate
-
10
16
See Note 1
Screw-Valve Flapper-Exhaust
-
4
17
See Note 1
Valve Plate Gasket
-
2
18
See Note 1
Valve Flapper-Intake & Exhaust
-
4
22
-
Connecting Rod
-
-
23
See Note 1
Diaphragm
2
-
24
See Note 1
Screw-Hold Down Plate
8
-
25
See Note 1
Hold Down Plate
2
-
26
See Note 1
PTFE Liner
2
-
Note 1: These parts are not available separately, but are supplied within kits.

13
Exploded View for 2090W-01
Parts List for
2090W-01
Item
No.
Part No.
Description
Diaphragm
Service Kit
2090K-01
Valve Plate
Service Kit
2090K-0 2
13
See Note 1
Valve Keeper
-
2
14
See Note 1
Screw-Valve Flapper-Intake
-
4
15
See Note 1
Screw-Valve Plate
-
10
16
See Note 1
Screw-Valve Flapper-Exhaust
-
4
17
See Note 1
Valve Plate Gasket
-
2
18
See Note 1
Valve Flapper-Intake & Exhaust
-
4
22
-
Connecting Rod
-
-
23
See Note 1
Diaphragm
2
-
24
See Note 1
Screw-Hold Down Plate
8
-
25
See Note 1
Hold Down Plate
2
-
26
See Note 1
PTFE Liner
2
-
Note 1: These parts are not available separately, but are supplied within kits.

14
Section 9: WARRANTY
UNPACKING
Inspect the pump carefully. If any damage has occurred, file claim with the carrier immediately. Save the shipping
container for carrier to inspect.
OPERATING PUMP
Refer to the enclosed Instruction/Operation Manual for all information to properly operate and maintain the pump.
WARRANTY
This Welch product is warranted to be free from defects in material and workmanship. The liability of GardnerDenver
Thomas under this warranty is limited to servicing, adjusting, repairing or replacing any unit or component part
which in the judgment of Gardner Denver Thomas has not been misused, abused or altered in any way causing
impaired performance or rendering it inoperative. No other warranties are expressed or implied. The method
of executing this warranty: servicing, adjusting, repairing or replacing shall be at the discretion of Gardner Denver
Thomas. Vacuum pumps that have been used for any period, however short, will be repaired under this warranty
rather than replaced.
The warranty is effective for one year from the date of original purchase when:
1. The warranty card has been completed and returned.
2. The product is returned to the factory or other designated service
centers, freight prepaid.
3. The product in our judgment is defective through no action or fault of the user.
If the product has become defective through misuse, abuse, or alteration, repairs will be billed regardless of the age
of the product. In this event, an estimate of the repair costs will be submitted and authorization of these charges
will be required before the product is repaired and returned.
To reduce additional charges and delays either within or outside of the warranty period, contact Welch at (847)-
676-8800 for a return authorization number. Products without a return authorization number will be refused by
our receiving department. Before shipping, properly pack the pump, insure it against loss or damage, and on the
outside of the pump packaging and the packing slip write in the return authorization number. Pumps damaged
due to improper packaging are the customer’s responsibility.

15
Notes
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Welch by Gardner Denver
1601 Feehanville Drive, Ste 550
Mount Prospect, IL 60056
Phone: [phone] (Technical Support)
Fax: [phone]
E-Mail: [e-mail]
Web-Page: www.welchvacuum.com
Copyright© 2013 Gardner Denver Welch Vacuum Technology, Inc.
Welch is registered trademarks of Gardner Denver