Desmi VAC-4001 Troubleshooting guide

DESMI self-priming centrifugal pump
Type VAC-4001
DESMI PUMPING TECHNOLOGY A/S
Tagholm 1 –DK-9400 Nørresundby –Denmark
Tel.:
[phone]
Fax:
[phone]
E-mail:
[email protected]
Internet:
www.desmi.com
Manual:
T1449
Language:
English
Revision:
C (03/19)
OPERATION AND MAINTENANCE INSTRUCTIONS

Table of Contents:
1. PRODUCT DESCRIPTION ................................................................................................................................. 3
1.1 DELIVERY............................................................................................................................................................. 3
2. TECHNICAL DATA ............................................................................................................................................. 3
2.1 NAME PLATE........................................................................................................................................................ 3
2.2 EXPLANATION OF THE TYPE NUMBER......................................................................................................... 3
2.3 TECHNICAL DESCRIPTION .............................................................................................................................. 4
3. INSTALLATION................................................................................................................................................... 4
3.1 MOUNTING/FASTENING ................................................................................................................................... 4
3.2WIRING.................................................................................................................................................................. 6
4. TRANSPORT/ STORAGE .................................................................................................................................. 6
5. DISMANTLING SEE DRAWING NO. 490231................................................................................................... 7
5.1 ACCESS TO IMPELLER AND ROTOR............................................................................................................. 7
5.2 DISMANTLING IMPELLER AND ROTOR......................................................................................................... 7
5.3 DISMANTLING SHAFT SEAL............................................................................................................................. 7
5.4 DISMANTLING SEAT........................................................................................................................................... 7
5.5 DISMANTLING SHAFT WITH BEARINGS ....................................................................................................... 7
5.6 INSPECTION......................................................................................................................................................... 7
6. ASSEMBLING...................................................................................................................................................... 7
6.1 FITTING SEALING RING IN PUMP CASING ................................................................................................... 7
6.2 FITTING SHAFT WITH BEARINGS................................................................................................................... 7
6.3 FITTING NYLON BUSHING................................................................................................................................ 8
6.4 FITTING SHAFT SEAL......................................................................................................................................... 8
6.5 FITTING ROTOR.................................................................................................................................................. 8
6.6 FITTING IMPELLER............................................................................................................................................. 8
6.7 FITTING BEARING BRACKET........................................................................................................................... 8
6.8 SHAFT.................................................................................................................................................................... 8
7. FROST PROTECTION........................................................................................................................................ 8
8. DISMANTLING..................................................................................................................................................... 9
9. START-UP............................................................................................................................................................ 9
9.1 STARTING............................................................................................................................................................. 9
10. SYSTEM BALANCING ..................................................................................................................................... 9
11. INSPECTION AND MAINTENANCE ..............................................................................................................11
11.1 DRAINING THE PUMP.................................................................................................................................... 11
11.2 BEARINGS........................................................................................................................................................ 11
12. REPAIRS...........................................................................................................................................................11
12.1 ORDERING SPARE PARTS........................................................................................................................... 11
13. OPERATING DATA..........................................................................................................................................11
14. EU DECLARATION OF CONFORMITY.........................................................................................................12
15. ASSEMBLY DRAWING...................................................................................................................................12
16. SPARE PARTS LIST........................................................................................................................................14
17. DIMENSIONAL SKETCH.................................................................................................................................15

DESMI PUMPING TECHNOLOGY A/S -3-
Tagholm 1
9400 Nørresundby - Denmark
Tel.: [phone]
Fax [phone]
E-mail: [e-mail] www.desmi.com
1. PRODUCT DESCRIPTION
This operation andmaintenance instructionapplies to the DESMI self-priming centrifugal pump, type
VAC-4001. The pump is available with DN100 on the suction and pressure flanges.
The VAC-4001 pump is a single-stage self-priming centrifugal pump with horizontal inlet and vertical
outlet at the top. The pump is equipped with a rotor which enables it to efficiently evacuate air from
the suction hose. Further the pump has stainless steel shaft and mechanical shaft seal.
The pump is suitable for pumping clean and polluted liquids with temperatures between 0 and 80ºC.
Max. number of revolutions is 3600 RPM.
The pump is particularly suitable for bilge pumping and for use in piping systems where large
amounts of air have to be evacuated.
The VAC-4001 pump is a quality product manufactured in accordance with ISO 9001.
1.1 DELIVERY
- Check on delivery that the shipment is complete and undamaged.
- Defects and damages, if any, to be reported to the carrier and the supplier
immediately in order that a claim can be advanced.
2. TECHNICAL DATA
2.1 NAME PLATE
Manufacturer:
DESMI
DK-9400 Nørresundby
Phone [phone]
Fax [phone]
e-mail: [e-mail]
http:\\www.desmi.com
TYPE: Pump type number
CODE NO.: Pump item No.
PUMP NO.: Pump No.
IMP.: Impeller diameter
WEEK/YEAR: Production week and year
The pumps are manufactured in various material combinations which appear from the type number
on the name plate.
2.2 EXPLANATION OF THE TYPE NUMBER
The VAC-4001 pump is provided with a name plate. The type number indicated on the name plate
is built up as follows:

DESMI PUMPING TECHNOLOGY A/S -4-
Tagholm 1
9400 Nørresundby - Denmark
Tel.: [phone]
Fax [phone]
E-mail: [e-mail] www.desmi.com
VAC-4001/M-R
M : The material combination of the pump.
R : The assembly combination of the pump.
M may be the following:
A : Standard. Casing: GG20. Impeller: Bronze. Rotor: Stainless steel
D : Casing: Rg5, Impeller: Bronze. Rotor: Stainless steel
E : Special alloy.
The pumps can be delivered in other material combinations, which are agreed with the supplier.
R may be the following:
01 : With electromagnetic clutch.
03 : With hydraulic motor.
04 : V-belt pulley and disengaging clutch.
07 : On base plate with petrol or diesel engine, or with electric motor.
09 : With bare shaft end.
10 : Special-tailored according to task.
Any use of the pump is to be evaluated on the basis of the materials used in the pump. In case of
doubt, contact the supplier.
Pumps in material combinations A are primarily used for fresh water.
Pumps in material combination D are primarily used for seawater.
2.3 TECHNICAL DESCRIPTION
The noise level of the pump depends on the motor type supplied, as the noise from the pump can
be calculated as the noise level of the motor + 2dB(A).
3. INSTALLATION
3.1 MOUNTING/FASTENING
The pump should be mounted and fastened on a solid base plate with a flat and horizontal surface
to avoid distortion. The pump must be mounted in such a way that the shaft centerline is horizontal.
When mounting a V-belt pulley on the pump a bore H7 is recommended. To facilitate the mounting
the hub in the V-belt pulley may be heated to about 100ºC after which the V-belt pulley is easily
lead over the shaft towards the shoulder. Alternatively, the V-belt pulley may be mounted with a
TAPER LOCK bush.

DESMI PUMPING TECHNOLOGY A/S -5-
Tagholm 1
9400 Nørresundby - Denmark
Tel.: [phone]
Fax [phone]
E-mail: [e-mail] www.desmi.com
When dimensioning the V-belt pulley it is important to follow the rules of the DESMI nomograms for
the pump size in question - contact DESMI.
Be careful when fitting the suction line to the pump so that it is absolutely tight, as even small
leakages may impede the priming. When pumping polluted liquids a strainer is necessary. The
strainer must be equipped with a sieve, the passage area of which is to be 3 x the area of the
suction pipe. The mesh size is to be 1-3 mm smaller than the impeller gap of the pump in question.
In order to secure priming of the pump the pressure pipe is to be arranged so that water locks in
the pipe are avoided.
If the pump is to be driven by a motor via a flexible coupling, motor and pump are to be placed on a
common base plate. The following should be observed:
- Avoid distortion of the base plate.
- Avoid distortion in the piping system.
- Check that pump and motor are aligned correctly.
Two proposals for alignment are indicated above. The deviations mentioned cover a complete
revolution of the coupling. The distance between the coupling halves is to be between 2 and
4 mm.
At installations pumping hot or very cold liquids, the operator must be aware that it is
dangerous to touch the pump surface, and, consequently, he must take the
necessary safety measures.

DESMI PUMPING TECHNOLOGY A/S -6-
Tagholm 1
9400 Nørresundby - Denmark
Tel.: [phone]
Fax [phone]
E-mail: [e-mail] www.desmi.com
When connecting the pump and a prime mover the power transmission is to be
equipped with a guard in accordance with the provisions of the COUNCIL DIRECTIVE.
3.2WIRING
Wiring to be carried out by authorised skilled workmen according to the rules and
regulations in force.
4. TRANSPORT/ STORAGE
The weights of the pumps are stated in the following table, and the pumps are to be lifted as shown
below.
Pump
Weight [kg]
VAC-4001/A09
85
VAC-4001/A07 excl. electric motor
100
VAC-4001/A02
155
The pumps are to be stored in a dry place.
Before shipment the pump is to be fastened securely on pallets or the like.
The pump is to be lifted as shown here:
Screw lifting eyes into the pressure flange and mount lifting straps
The lifting straps must not bear against sharp edges and corners.

DESMI PUMPING TECHNOLOGY A/S -7-
Tagholm 1
9400 Nørresundby - Denmark
Tel.: [phone]
Fax [phone]
E-mail: [e-mail] www.desmi.com
5. DISMANTLING SEE DRAWING NO.490231
Before dismantling the pump, drain the bearing bracket of oil. Unscrew stud (31) and drain the oil
into a bucket.
5.1 ACCESS TO IMPELLER AND ROTOR
Remove M12 nuts (1), which hold the bearing bracket (3) to the pump casing. Pull the bearing
bracket (3) to remove the complete bearing bracket with rotor, impeller, bearings, and shaft.
Remove the O-ring (12).
5.2 DISMANTLING IMPELLER AND ROTOR
Remove impeller nut (21) and washer (37). Pull off the impeller (19). Remove Allen screws (15),
which hold the rotor housing (17) to the rear plate (14). Remove the rotor housing (17). Pull key
(20) and rotor (16) off the shaft (5). Take care not to damage the seat which is mounted in the
rotor. Remove rear plate (14) and nylon bushing (13).
5.3 DISMANTLING SHAFT SEAL
Pull the shaft seal off the shaft.
5.4 DISMANTLING SEAT
Pull the shaft seal seat carefully out of the recess of the rotor hub.
5.5 DISMANTLING SHAFTWITH BEARINGS
Before dismantling the shaft (5) with bearings (9-33), remove the lock ring (4) and the oil sealing
ring (8). The shaft can now be pulled out of the bearing bracket allowing inspection of the bearings.
5.6 INSPECTION
When the pump has been dismantled, check the following parts for wear and damage:
- Sealing ring/impeller: Max. clearance 0.4-0.5 mm measured in radius
- Shaft seal: Check wear ring and seat for flatness and cracks.
Check the rubber parts for elasticity and scratches.
- Bearing: Replace in case of wear and noise
- Rotor: Check the rotor for damages
- Nylon bushing: Check for wear
6. ASSEMBLING
6.1 FITTING SEALING RING IN PUMP CASING
When fitted, the sealing ring (22) is to bear against the shoulder of the pump casing.
6.2 FITTING SHAFTWITH BEARINGS
Lead shaft with bearings into the bearing bracket. Fit oil sealing ring (8) and lock ring (4)

DESMI PUMPING TECHNOLOGY A/S -8-
Tagholm 1
9400 Nørresundby - Denmark
Tel.: [phone]
Fax [phone]
E-mail: [e-mail] www.desmi.com
6.3 FITTING NYLON BUSHING
Press nylon bushing (13) into place in the bearing bracket hub.
6.4 FITTING SHAFT SEAL
Before fitting the seat, clean the recess in the rotor. When fitting the seat, remove the protective
coating, if any, without scratching the lapped surface. Dip the outer rubber ring of the seat into
soapy water. Now press the seat into place with the fingers and check that all parts are correctly
imbedded. If it is necessary to use tools for assembling, protect the sliding surface of the seat to
prevent it from being scratched or cut. Lubricate the inner diameter of the slide ring rubber bellows
with soapy water and push it over the shaft. The use of a fitting bush as shown on the below
assembly drawing is recommended to avoid that the rubber bellows is cut. Push the slide ring over
the shaft with the hand. If the rubber bellows is tight, use a fitting tool and take care that the slide
ring is not damaged.
If the carbon ring is not fixed, it is important to check that it is fitted correctly, i.e. the
chamfered/lapped side is to face the seat. The carbon ring can be held by a little grease.
When using oil on the shaft, the bellows will settle and seat in about 15 minutes, and until then
tightness should not be expected.
6.5 FITTING ROTOR
Fit locating pin (18) in the rotor hub. Place rear plate (14) in the recess of the nylon bushing and
lead the rotor over the shaft and against the shoulder of the shaft. Mount the rotor housing (17) on
the rear plate (14) by means of the Allen screws (15).
6.6 FITTING IMPELLER
Fit the sunk key (9) in the shaft and lead the impeller towards the shoulder of the shaft. Take care
that the pin is placed in the hole of the impeller hub. Secure the impeller with a washer (37) and a
nut (21).
6.7 FITTING BEARING BRACKET
Place the O-ring (12) that seals between pump casing and bearing bracket on the bearing bracket
where it can be held with a little silicone grease. Lead bearing bracket into place and fasten with
nuts (1). Mount drain plug (7) and fill bearing bracket with oil (SAE 15W40) until half the shaft is
covered.
6.8 SHAFT
When the pump has been assembled, check that the shaft rotates freely.
7. FROST PROTECTION
Pumps which are not in operation during frost periods are to be drained to avoid frost damage.
Remove the drain bolt (32) at the bottom to empty the pump. Alternatively, it is possible to use anti-
freeze liquids in normal constructions.
Fitting bush

DESMI PUMPING TECHNOLOGY A/S -9-
Tagholm 1
9400 Nørresundby - Denmark
Tel.: [phone]
Fax [phone]
E-mail: [e-mail] www.desmi.com
8. DISMANTLING
Before dismantling the pump make sure that it has stopped. Empty the pump of
liquid before it is dismantled from the piping system. If the pump has been pumping
dangerous liquids you are to be aware of this and take the necessary safety
measures. If the pump has been pumping hot liquids, take great care that it is
drained before it is removed from the piping system. If cold or very hot liquids have
been pumped, the operator must be aware that it is dangerous to touch the pump
surface and he must, consequently, take the necessary safety measures.
9. START-UP
A self-priming centrifugal pump will not function until the pump casing has been filled
with liquid.
The liquid also serves as coolant for the shaft seal. In order to protect the shaft seal
the pump must not run dry.
WARNING
For safety reasons the pump is only allowed to operate against closed discharge valve for a short
time (max. 5 minutes and at a max. temperature of 80°C for standard pumps). Otherwise there is a
risk of damage to the pump and, at worst, of a steam explosion. If the pump is not monitored, the
installation of a safety device is recommended.
9.1 STARTING
Before starting the pump check that
- the shaft rotates freely without noise
- the pump casing is filled with liquid.
Start the pump for a moment to check direction of rotation. If the direction is correct (i.e. in the
direction of the arrow), the pump may be started.
10. SYSTEM BALANCING
It is often difficult to calculate a manometric delivery head in advance. It is, however, decisively
important to the quantity of liquid delivered. A considerably smaller delivery head than expected
will increase the quantity of liquid delivered, causing increased power consumption and perhaps
cavitation in pump and piping. In the pump the impeller may show signs of heavy erosion caused
by cavitation (corrosion) which may at times render an impeller unfit for use in a very short time.
Not unusually do similar erosions occur in pipe bends and valves elsewhere in the piping system.
Therefore, after start-up, it is necessary to check either the quantity of liquid delivered or the power
consumption of the pump e.g. by measuring the current intensity of the connected motor. Together
with a reading of the differential pressure the quantity of water delivered can be determined against
the characteristics of the pump.
In cases where the liquid flow of the pump has to be reduced a valve in the piping system is the
most common solution. This valve always has to be placed on the suction side of the pump - never
on the delivery side.
Should the pump not function as intended, please proceed according to the fault-finding list. Bear
in mind, though, that the pump was carefully checked and tested at the factory and that the
majority of faults stem from the piping system.

DESMI PUMPING TECHNOLOGY A/S -10-
Tagholm 1
9400 Nørresundby - Denmark
Tel.: [phone]
Fax [phone]
E-mail: [e-mail] www.desmi.com
FAULT
CAUSE
REMEDY
The pump does not
prime
1. The pump is not filled
with liquid
2. Leaking non-return
valve in pump
3. Wrong direction of
rotation
4. Air is drawn in because
of too little liquid or
leaking suction line
5. Liquid lock in outlet
line
6. Temperature of liquid
too high
7. Air cannot escape on
pressure side
Fill pump casing with liquid
Remove foreign body in
valve/Remove any coating
on mating faces
Change direction of rotation
Lower suction pipe/ Tighten
suction line
Change the pressure line so
that the air can pass out
freely
Replace liquid in pump
casing/Wrong dimen-
sioning/Contact DESMI
Ventilate the system
The pump has no or too
low capacity
1. Wrong direction of
rotation
2. Piping system choked
3. The pump is choked
4. Suction line leaks
Pump takes air
5. Suction lift too high
6. Pump and piping system
wrongly dimensioned
Change direction of rotation
to clockwise when viewed
from shaft end (the direction
of the arrow)
Clean or replace
Clean the pump
Find the leakage/repair the
fault, non-return valve not
submerged
Check data sheet Q/H curve
and NPSH or contact
DESMI
As 5
The pump uses too
much power
1. Counter-pressure too
low
2. The liquid is heavier
than water
3. Foreign body in pump
4. Electric motor is
running on 2 phases
Insert orifice plate or check
valve/Contact DESMI
Contact DESMI
Dismantle the pump,
remove the cause
Check fuses, cable
connection, and cable
The pump makes noise
1. Cavitation in pump
Suction lift too high/
Suction line wrongly
dimensioned/Liquid
temperature too high

DESMI PUMPING TECHNOLOGY A/S -11-
Tagholm 1
9400 Nørresundby - Denmark
Tel.: [phone]
Fax [phone]
E-mail: [e-mail] www.desmi.com
11. INSPECTION AND MAINTENANCE
Inspect the shaft seal for leaks at regular intervals.
This is done by checking the oil inside the bearing bracket. If the shaft seal is leaking the oil
becomes white.
- Before inspection of a pump without guard check that the pump cannot be .......started
unintentionally.
- The system is to be without pressure and drained of liquid.
- The repairman must be familiar with the type of liquid that has been pumped as well as the
safety measures he is to take when handling the liquid.
11.1 DRAINING THE PUMP
When the piping system has been drained, note that there is still liquid in the pump. Remove the
liquid by dismantling the drain bolt (32) at the bottom of the pump.
11.2 BEARINGS
The pump is equipped with deep groove ball bearings with a nominal life of 25,000 working hours
when direct coupled to electric motor, whereas the nominal life with overhanging V-belt drive is
about 10,000 working hours. The bearings are oil lubricated and they only require that the oil level
in the bearing bracket is correct. However, they should be replaced in case of noise or bearing
wear. In connection with a leaking shaft seal where water has penetrated the bearings, inspect
these for damages and replace is necessary.
12. REPAIRS
12.1 ORDERING SPARE PARTS
When ordering spare parts please always state pump type and pump no. (available from the name
plate of the pump). See also spare parts drawing with item nos.
13. OPERATING DATA
The following working pressures are allowed
PUMP
VAC-4001
Pressure [mWC]
35
(10.2 mWC = 1 bar)
The above-mentioned max. working pressure is NOT valid for pumps approved by a classification
society. Pumps approved by classification societies have been pressure tested according to the
requirements of these societies, i.e. a test pressure of 1.5 x the permissible working pressure. The
test pressure is stated in the test certificate and stamped into the discharge flange of the pump.

DESMI PUMPING TECHNOLOGY A/S -12-
Tagholm 1
9400 Nørresundby - Denmark
Tel.: [phone]
Fax [phone]
E-mail: [e-mail] www.desmi.com
14. EU DECLARATION OF CONFORMITY
DESMI PUMPING TECHNOLOGY A/S, hereby declare that our pumps of the type VAC-
4001 are manufactured in conformity with the following essential safety and health
requirements in the COUNCIL DIRECTIVE 2006/42/EC on machines, Annex 1.
The following harmonized standards have been used:
EN/ISO 13857:2008
Safety of machinery. Safety distances to prevent danger zones
being reached by the upper limbs
EN 809:1998 + A1:2009
Pumps and pump units for liquids –Common safety requirements
EN12162:2001+A1:2009
Liquid pumps –Safety requirements –Procedure for hydrostatic
testing
EN 60204-1:2006/A1:2009
Safety of machinery –Electrical equipment of machines (item 4,
General requirements)
Ecodesign Directive
(2009/125/EC).
Water pumps:
Commission Regulation No 547/2012.
Applies only to water pumps marked with the minimum efficiency
index MEI. See pump nameplate.
Pumps delivered by us connected with prime movers are CE-marked and comply with the
above requirements.
Pumps delivered by us without prime movers (as partly completed machinery) must only be
used when the prime mover and the connection between prime mover and pump comply
with the above requirements.
Nørresundby, Marts 05 2019
Henrik Mørkholt Sørensen
Managing Director
DESMI Pumping Technology A/S
Tagholm 1
9400 Nørresundby

DESMI PUMPING TECHNOLOGY A/S -13-
Tagholm 1
9400 Nørresundby - Denmark
Tel.: [phone]
Fax [phone]
E-mail: [e-mail] www.desmi.com
15. ASSEMBLY DRAWING

DESMI PUMPING TECHNOLOGY A/S -14-
Tagholm 1
9400 Nørresundby - Denmark
Tel.: [phone]
Fax [phone]
E-mail: [e-mail] www.desmi.com
16. SPARE PARTS LIST
Pos. No. Description Qty. Item No.
01 Nut M12 6 704063
02 Stud M12x25 6 708883
03 Bearing bracket 1 590750
04 Lock ring 1 701112
05 Shaft 1 590770
06 Lock ring 1 701125
07 Drain plug 3/8” BSP 1 2037505
08 Oil sealing ring 1 701292
09 Ball bearing 6010-2RS1 1 703381
10 Nipple 3/8”x40 1 710938
11 End plug 3/8” RG 1 190530
12 O-ring 1 710945
13 Nylon bushing 1 590760
14 Rear plate for rotor housing 1 190531
15 Allen screw M5x30 4 710940
16 Rotor 1 190532
17 Rotor housing 1 190533
18 Locating pin ø4x18 1 706284
19 Impeller 1 590730
20 Key 5x5x20 1 700012
21 Impeller nut M18x1.5 1 710943
22 Wear ring 1 590720
23 Stud M16x40 A4 8 710935
24 Nut M16 A4 8 704037
25 Filling plug 3/4” 1 706970
26 Stud M16x40 A4 8 710935
27 Nut M16 A4 8 704037
28 Gasket for inspection cover 1 190528
29 Inspection cover 1 190529
30 Nyloc nut M12 2 703232
31 Stud M12x25 A4 2 708883
32 Drain bolt 3/4” 1 190527
33 Ball bearing 5205 1 710937
34 Shaft seal 1 710936
36 O-ring for rotor housing 1 710946
37 Lock washer M18 1 710944
38 Pump casing 1 590710
39 Shaft end 1 590780
40 Allen screw M10x170 A4 1 710947
41 Key 7x8x50 1 706834
42 Key 7x8x40 1 700021

DESMI PUMPING TECHNOLOGY A/S -15-
Tagholm 1
9400 Nørresundby - Denmark
Tel.: [phone]
Fax [phone]
E-mail: [e-mail] www.desmi.com
17. DIMENSIONAL SKETCH