Desmi DSL 300-320 Manual

OPERATION AND MAINTENANCE INSTRUCTION
DESMI “in-line” centrifugal pump
Type DSL
DESMI Pumping Technology A/S
Tagholm 1 –DK-9400 Nørresundby –Denmark
Tel.:
[phone]
Fax:
[phone]
E-mail:
[email protected]
Internet:
www.desmi.com
Manual:
T1343
Language:
English
Revision:
Q (12/19)
Special pump No. .................................................

Contents
1. PRODUCT DESCRIPTION................................................................................................................................... 4
1.1 DELIVERY ............................................................................................................................................................... 4
2. TECHNICAL DATA ............................................................................................................................................... 4
2.1 ACCESSORIES ...................................................................................................................................................... 4
2.2 SPACE AROUND THE PUMP.............................................................................................................................. 4
2.3 EXPLANATION OF THE TYPE NUMBER........................................................................................................... 5
2.4 TECHNICAL DESCRIPTION ................................................................................................................................ 6
3. INSTALLATION..................................................................................................................................................... 7
3.1 MOUNTING/FASTENING...................................................................................................................................... 7
3.2WIRING.................................................................................................................................................................... 8
4. TRANSPORT/STORAGE ..................................................................................................................................... 8
5. DISMANTLING....................................................................................................................................................... 8
5.1 DISMANTLING MOTOR AND BRACKET........................................................................................................... 8
5.2 DISMANTLING COUPLING ................................................................................................................................. 8
5.3 DISMANTLING TOP BEARING AND SHAFT SEAL......................................................................................... 8
5.4 DISMANTLING BOTTOM BEARING .................................................................................................................. 9
5.5 DISMANTLING BOTTOM SHAFT SEAL............................................................................................................. 9
5.6 DISMANTLING REAR COVER WITH SHAFT AND IMPELLER...................................................................... 9
6. ASSEMBLING.......................................................................................................................................................10
6.1 FITTING SEALING RING AND IMPELLER....................................................................................................... 10
6.2 FITTING TOP BEARING AND SHAFT SEAL.................................................................................................... 10
6.3 FITTING REAR COVER WITH SHAFT AND IMPELLER................................................................................ 10
6.4 FITTING BOTTOM SHAFT SEAL....................................................................................................................... 10
6.5 FITTING BOTTOM BEARING............................................................................................................................. 11
6.6 FITTING COUPLING............................................................................................................................................ 11
6.7 COUPLING GUARD............................................................................................................................................. 12
7. FROST PROTECTION.........................................................................................................................................12
8. DISMANTLING......................................................................................................................................................12
9. START-UP.............................................................................................................................................................12
9.1 STARTING............................................................................................................................................................. 13
10. SYSTEM BALANCING ......................................................................................................................................13
10.1 FAULT-FINDING CHART.................................................................................................................................. 14
11. INSPECTION AND MAINTENANCE ................................................................................................................16
11.1 INSPECTION DURING OPERATION.............................................................................................................. 16
11.2 DRAINING THE PUMP...................................................................................................................................... 16
11.3 INSPECTION ...................................................................................................................................................... 16
11.4 LUBRICATING BEARINGS............................................................................................................................... 16
12. REPAIRS.............................................................................................................................................................18
12.1 ORDERING SPARE PARTS............................................................................................................................. 18
13. OPERATING DATA............................................................................................................................................19
14. EU DECLARATION OF CONFORMITY...........................................................................................................20

15. INFORMATION RELEVANT FOR DISASSEMBLY OR DISPOSAL AT END-OF-LIFE..............................21
16. ASSEMBLY DRAWING.....................................................................................................................................22
16.1 DSL300 SPACER DESIGNWITH BOTTOM ROLLER BEARING............................................................... 22
16.2 DSL300 COMPACT DESIGN WITH BOTTOM ROLLER BEARING........................................................... 24
16.3 DSL300 SPACER DESIGNWITH BOTTOM SLIDING BEARING............................................................... 26
16.4 DSL300 COMPACT DESIGN WITH BOTTOM SLIDING BEARING........................................................... 28
16.5 DSL400 SPACER DESIGNWITH BOTTOM ROLLER BEARING............................................................... 30
16.6 DSL400 COMPACT DESIGN WITH BOTTOM ROLLER BEARING........................................................... 32
16.7 DSL400 SPACER DESIGNWITH BOTTOM SLIDING BEARING............................................................... 34
16.8 DSL400 COMPACT DESIGN WITH BOTTOM SLIDING BEARING........................................................... 36
17. DIMENSIONAL SKETCH (DESIGN BEFORE 2006)......................................................................................38
18. DIMENSIONAL SKETCH (DESIGN AFTER 2006) .........................................................................................38

______________________________________________________________________________
DESMI Pumping Technology A/S 4
Tagholm 1
9400 Nørresundby –Denmark
Tel: [phone] Fax: [phone]
E-mail: [email protected] www.desmi.com
1. PRODUCT DESCRIPTION
These operation and maintenance instructions apply to the DESMI DSL-pump series, in spacer and
compact design. The pumps are available in sizes ranging from 300 mm to 400 mm on the pressure
flange. The suction flange is bigger than the pressure flange.
The DESMI DSL-pump isa 1-stage centrifugal pump with stainless steelshaft, mechanical shaft seals
and closed impeller of the double-suction type.
The pump is a so-called "in-line" type, i.e. suction and pressure branches are mounted on the centre
line. It is vertical with impeller of the double-suction type with double-curved blades, and it has a
helical pump casing in one casting.
The pump is driven by an electric motor which may be a standard AC motor or a DC motor.
1.1 DELIVERY
-Check on delivery that the shipment is complete and undamaged.
-Defects and damages, if any, to be reported to the carrier or the supplier immediately in
order that a claim can be advanced.
2. TECHNICAL DATA
The pumps are manufactured in various material combinations which appear from the type number
on the name plate. See paragraph 2.3.
2.1 ACCESSORIES
As extra equipment the pump may be mounted with a priming pump of the water ring type, complete
with filter and feed water tank, or it may be delivered with an ejector pump.
Manometers are standard equipment.
2.2 SPACE AROUND THE PUMP
On the spacer pump it is possible to dismantle the impeller and the shaft without dismantling the
electric motor. Therefore, no minimum distance is required above the electric motor. The ventilation
of the motor should, however, be taken into consideration.
On the compact pump the motor and the motor bracket must be removed before dismantling shaft
and impeller. This means that there is to be so much space above the motor that motor with bracket
can be lifted abt. 250 mm up.
Generally, there is to be sufficient space in front of the pump to allow inspection of the shaft seal for
leaks and dismantling of the coupling and the internal parts of the pump. It must also be possible to
dismantle the entire pump, if required.
If the pump is equipped with a slide bearing at the bottom, there is to be a distance of abt. 100 mm
under the middle of the pump measured from the pump feet for dismantling of the slide bearing. In
the standard pump type, i.e. roller bearing and shaft seal at the bottom, this is not

______________________________________________________________________________
DESMI Pumping Technology A/S 5
Tagholm 1
9400 Nørresundby –Denmark
Tel: [phone] Fax: [phone]
E-mail: [email protected] www.desmi.com
necessary, but nevertheless it would be an advantage to provide space under the pump, as it would
facilitate the servicing of the bottom bearing of the pump and the shaft seal considerably.
2.3 EXPLANATION OF THE TYPE NUMBER
All the DSL-pumps are provided with a name plate. The type number indicated on the name plate is
built up as follows:
DSL-XXX-YYY/M-R
XXX : Diameter DN (mm) of the pressure branch (300, 400)
YYY : Diameter (mm) of standard impeller (320, 465, 495).
M : The material combination of the pump.
R : The assembly combination of the pump.
R may be the following:
a : Spacer design. l : Other shaft seal.
b : Spacer design without bottom bearing. m : BS-flanges.
f : Compact design. n : ANSI-flanges.
g : Compact design without bottom bearing. o : Shock-proof combination.
i : With PN 16 flanges. p : Other combination.
j : With PN 25 flanges. q : JIS-flanges.
k : Identical suction and pressure
Flanges.
M may be the following:
Material
combination
A
C
D
Q
Pump casing
Cast iron
Cast iron
Bronze
See note 1)
Impeller
Alu-bronze
Cast iron
Alu-bronze
See note 1)
Sealing ring
Alu-bronze
Cast iron
Alu-bronze
See note 1)
Rear cover
Cast iron
Cast iron
Bronze
See note 1)
Shaft
Stainless steel
Stainless steel
Stainless steel
Stainless steel
Shaft seal
Mechanical
Mechanical
Mechanical
Mechanical
Elastomer
Nitrile
Nitrile
Nitrile
Nitrile
Note 1): The pumps are available in other material combinations at request.
Before putting a pump into operation, the suitability of the material combination of the pump must
always be taken into consideration. In case of doubt, contact the supplier.
The pump is suitable for the pumping of liquids with temperatures up to 80°C. With special shaft seal

______________________________________________________________________________
DESMI Pumping Technology A/S 6
Tagholm 1
9400 Nørresundby –Denmark
Tel: [phone] Fax: [phone]
E-mail: [email protected] www.desmi.com
and bearings up to 140°C.
The pump is particularly suitable for the pumping of water in connection with the cooling of diesel
engines and cooling units, as ballast pump, and for waterworks and district heating stations.
Pumps in material combinations A and C are primarily used for fresh water.
Pumps in material combination D are primarily used for sea water.
If the pumps are designed for special purposes, the following is to be indicated:
Pump No. ...........:_______________________________________________________
Pump type ..........:_______________________________________________________
Application ...........:_______________________________________________________
Comment ...........:_______________________________________________________
2.4 TECHNICAL DESCRIPTION
The pumps are as a standard equipped with an electric motor with protection class IP
54.This means that the motor is protected against penetrating dust, and that splashes of
water without pressure do not ruin the motor. If the pumps are installed in explosive areas
they must be equipped with explosion-proof motors. The motors are designed for
continuous operation at a max. ambient temperature of 40°C.
The following table indicatesthe max. permissible numberof revolutions forthe individual pump types:
Pump type
Motors:
6-pole / 50 Hz
6-pole / 60 Hz
Motors:
4-pole / 50 Hz
4-pole/ 60 Hz
DSL 300-320
√
DSL 400-430
√
DSL 400-495
√
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 + 2 dB (A).
The capacity of the pump appears on the name plate of the pump. If the pump has been delivered
without motor, the pump capacity is to be indicated on the plate when mounting the motor.

______________________________________________________________________________
DESMI Pumping Technology A/S 7
Tagholm 1
9400 Nørresundby –Denmark
Tel: [phone] Fax: [phone]
E-mail: [email protected] www.desmi.com
The permissible loads on the flanges are stated in the table below:
Pump type
DN
Forces (N)
Torques (Nm)
Fy
Fz
Fx
∑
My
Mz
Mx
∑Mt
DSL 300-320
300
3000
3750
3350
5860
2750
1900
2200
4000
DSL 400-430
400
4000
5000
4480
7820
4600
3200
3700
6720
DSL 400-495
400
4000
5000
4480
7820
4600
3200
3700
6720
In connection with the permissible loads on the flanges stated in the above table there is also the
following limitation :
2
22






















t
M
calcM
F
calcF
where index "calc" is the values calculated by the user.
The permissible loads on the flanges appear from the following table. The values apply to standard
pumps in bronze (Rg5) and cast iron (GG20). As to pumps in SG iron (GGG40) or NiAlBz the values
are to be increased by factor 1.5.
At the same time none of the forces or moments may exceed the indicated figure multiplied by 1.4.
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 max. permissible loads on the flanges indicated in paragraph 2.4 are to be observed.
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 8
Tagholm 1
9400 Nørresundby –Denmark
Tel: [phone] Fax: [phone]
E-mail: [email protected] www.desmi.com
3.2 WIRING
Wiring to be carried out by authorized skilled workmen according to the rules and
regulations in force.
4. TRANSPORT/STORAGE
The pumps are to be lifted as shown on the figure. The
weight appears from the table below.
The pump is to be stored in a dry area.
The centre of gravity of the pump is on the centre line
of the shaft.
Before shipment the pump is to be fastened and supported
securely on a pallet or the like.
The pump is to be lifted as follows:
The lifting straps must not bear against
sharp edges and corners.
The pump weights do not include motor.
PUMP TYPE
WEIGHT IN KG
SPACER
A/D-
COMBINATION
WEIGHT IN KG COMPACT
A/D-COMBINATION
DSL 300-320
710/795
645/730
DSL 400-430
1360/1520
1240/1400
DSL 400-495
1366/1526
1246/1406
5. DISMANTLING
5.1 DISMANTLING MOTOR AND BRACKET
Normally, it will not be necessary to dismantle motor and bracket in the spacer pump, whereas it has
to be done in the compact type. Remove the copper pipes to the manometers and the rear cover,
then unscrew the nuts (920.1) . Motor with bracket can now be lifted up and out. It is also possible to
dismantle the motor only by removing the screws (901.1).
5.2 DISMANTLING COUPLING
The spacer shaft (860.1) can be taken out after the screws (914.5) have been removed. Pull the pump
half off the shaft. In the compact pump the motor has to be removed before the coupling can be
dismantled as described in paragraph 5.1.
5.3 DISMANTLING TOP BEARING AND SHAFT SEAL
Dismantle the bearing cover (360.1). Remove the circlip (932.1). Pull out carefully the bearing with
bearing housing by means of the threads of the bearing housing (382.1). Press out the bearing from
behind the bearing housing. Press out the ceramic ring of the shaft seal (433.1) from the cover, and
pull up the remaining components of the shaft seal.

______________________________________________________________________________
DESMI Pumping Technology A/S 9
Tagholm 1
9400 Nørresundby –Denmark
Tel: [phone] Fax: [phone]
E-mail: [email protected] www.desmi.com
5.4 DISMANTLING BOTTOM BEARING
Dismantle the four screws (914.3). Pull down bearing housing (382.2) with outer ring and rollers. If
the bearing has to be replaced, it is necessary to dismantle the inner ring. Remove the circlip (932.2)
and heat the inner ring by means of a heating ring. Press out the outer ring from the bearing housing
after the bearing cover has been removed.
The procedure is the same if the bottom bearing of the pump is a slide bearing with the only exception
that instead of the outer ring it is the slide bearing (310.1) which follows the bearing housing. The
shaft lining can be pulled off after the shaft nut (922.2) has been removed. If the slide bearing has to
be replaced, it can be pressed out of the housing.
5.5 DISMANTLING BOTTOM SHAFT SEAL
Dismantle the bearing housing as described in paragraph 5.4. Loosen the screws holding the shaft
seal housing (441.1) and pull out the shaft seal housing. Remove intermediate ring (550.1 it is not
found in all the pumps) and the water deflector from the housing. Press the ceramic ring of the shaft
seal (433.2) out of the housing. Pull the remaining seal components off the shaft.
If the bottom bearing of the pump is a slide bearing, there is no mechanical shaft seal at the bottom.
5.6 DISMANTLING REAR COVER WITH SHAFT AND IMPELLER
This operation offers 3 different possibilities dependent onthe aids available. First, dismantle coupling
and bottom bearing/shaft seal as described in paragraphs 5.2, 5.4, and 5.5.
A. Crane/Lifting Hoist available and sufficient space above motor:
Remove motor with bracket as described in paragraph 5.1. It is not necessary to remove the motor
bracket, if the rear cover can pass the top flange in the bracket. Remove the nuts (920.1) which hold
the rear cover. Mount a lifting eye at the shaft end and lift up the complete arrangement. Loosen the
pointed screw (904.3), remove the shaft nut (922.1), and pull the impeller off the shaft. Now check the
sealing rings (502.1) for wear.
B. Lifting Hoist Available:
This possibility applies to the spacer pump only. Remove the nuts (920.3) which hold the rear cover.
Dismantle the copper pipe to the rear cover. Mount lifting eyes in the rear cover and at the top of the
motor bracket. Pull up the complete arrangement bymeans of hoists andtip it outthrough the opening
of the motor bracket. Follow item A.
C. Limited Lifting Possibilities:
This possibility applies to the spacer design only. Dismantle the top bearing and the shaft seal as
described in paragraph 5.3. Remove the nuts (920.3) which hold the rear cover. Dismantle the copper
pipe to the rear cover. Dismantle the rear cover, e.g. by means of a pulley drawer. Pull up the shaft
with impeller. Follow item A.

______________________________________________________________________________
DESMI Pumping Technology A/S 10
Tagholm 1
9400 Nørresundby –Denmark
Tel: [phone] Fax: [phone]
E-mail: [email protected] www.desmi.com
6. ASSEMBLING
6.1 FITTING SEALING RING AND IMPELLER
Press the sealing ring into place. It is to bear against the shoulders of pump casing and rear cover.
Fit the keys (940.3) in the shaft, and lead the impeller towards the shoulder of the shaft. Tighten the
shaft nut (922.1). Tighten the pointed screw (904.4). Lead the shaft with impeller into the rear cover
(130.1).
6.2 FITTING TOP BEARING AND SHAFT SEAL
Before fitting the seat, clean the recess in the bearing housing (382.1). Dip the outer rubber ring of
the seat into olive oil (or another neutral oil) or in silicone grease. Now press the seat into place with
the fingers and check that it is correctly embedded. If it is necessary to use fitting tools, then protect
the sliding surface of the seat to prevent it from being scratched or cut. Lubricate the inner diameter
of the rubber bellows of the slide ring and the shaft piece under the rubber bellows with silicone grease.
Lead the slide ring unit down over the shaft and make sure that the slide ring is protected. Push the
slide ring down along the shaft until the spring locates over the thrust collar and contacts the shell.
Push and compress thespring.When you let go of the seal, the slide ring unit is to move slowlyacross
the shaft. 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. Push the O-ring (412.3) into place in the track of the bearing
housing, then lead the bearing housing with the ceramic ring carefully down over the shaft. Tighten
the screws (914.4). When using oil or silicone grease on the shaft, the bellows will settle and seat in
about 15 minutes, and until then tightness should not be expected. After start, check by viewing the
leak hole that that there are no leaks.
When replacing the shaft seal the bearing (321.1) should also be replaced. Lead the support disc
(505.1) down over the shaft, and press the bearing (321.1) into place. Use pressing tools which are
fitted by means of the thread in the shaft end. Lead down the other support disc, and fit the circlip
(932.1). Fit the bearing cover.
6.3 FITTING REAR COVER WITH SHAFT AND IMPELLER
Fit the O-rings (412.1) and (412.4) in the rear cover and use a little grease. If there is only 1 0-ring in
the rear cover, use the gasket (400.2) between rear cover and pump casing instead. Lower rear cover
with shaft and impeller into the pump casing. Fit the rear cover by tightening the nuts (920.3), as there
is resistance from the O-rings.
6.4 FITTING BOTTOM SHAFT SEAL
Before fitting the seat, clean the recess in the shaft seal housing (441.1). Dip the outer rubber ring of
the seat in olive oil (or another neutral oil) or in silicone grease. Now press the seat into place with
the fingers and check that it is correctly imbedded. If it is necessary to use fitting tools, then protect
the sliding surface of the seat to prevent it from being scratched or cut. Lubricate the inner diameter
of the rubber bellows of the slide ring and the shaft piece under the rubber bellows with silicone grease.
Lead the slide ring unit over the shaft and make sure that the slide ring is protected. Push the slide
ring along the shaft until the spring locates over the thrust collar and contacts the shell. Push and
compress the spring. When you let go of the sealing the slide ring unit is to move slowly across the
shaft. 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.Lead the O-ring or the gasket into place in the bearing
housing (441.1). Lead the bearing housing carefully up over the shaft and tighten the screws (914.1).
When using oil or silicone grease on the shaft the bellows will settle and seat in about 15 minutes,
and until then tightness should not be expected. After start, check for leaks by viewing the leak hole.

______________________________________________________________________________
DESMI Pumping Technology A/S 11
Tagholm 1
9400 Nørresundby –Denmark
Tel: [phone] Fax: [phone]
E-mail: [email protected] www.desmi.com
6.5 FITTING BOTTOM BEARING
If a new bearing has to be mounted, heat the inner ring of the new bearing with a heating ring and
lead the bearing into place on the shaft. Fit the circlip (932.2). Press the outer ring with rollers into
place in the bearing housing. Tighten the bearing cover. Push up the water deflector (507.1) until it
bears against the shoulder of the shaft. Fit the intermediate ring (550.1 is not found on all the pumps).
Then fit the O-ring in the track of bearing housing. Lead bearing housing with outer ring and rollers
into place and tighten.
Remember to fill the bearing completely and the bearing housing approx. 1/3 with grease during
assembly
(Use approx. 40 grams of grease in DSL 300 and 60 grams in DSL 400).
If the pump is equipped with slide bearing at the bottom, and this has to be replaced, press a new
slide bearing (310.1) into the bearing housing (382.2) until it bears against the shoulder. Lead the O-
ring into place in the bearing housing. Fit the key (940.4) in the shaft and push the shaft lining (524.1)
onto the shaft so that it catches the key. Tighten and and secure the shaft nut (922.2) by means of
the pointed screw (904.3). Lead the bearing housing with slide bearing up and see to it that the pin is
guided into the little hole in the pump casing Lead the O-ring (412.5) into place in the bottom cover
(361.1). Tighten the cover and make sure that the pin is guided into the hole of the bearing housing.
6.6 FITTING COUPLING
Fit the key (940.2) in the shaft. Press the coupling half against the shoulder of the shaft and fasten it
with the pointed screw (904.1).
If the pump is a spacer, proceed with the assembling as follows:
1. Inspect Allen screws (914.5) and coupling bushes (867.1)for damage and clean themwith a cloth.
Replace screws or bushes if damaged!
2. Degrease the screw threads with e.g. benzine and clean the threaded holes in the coupling half
pump and coupling half motor with compressed air. If new coupling halves are mounted at the
same time, clean the threaded holes with benzine as well.
3. Place the coupling bushes in the top holes of the spacer (860.1). The chamfering on the bushes
to face downwards! Place the coupling bushes in the bottom holes of the spacer. The chamfering
on the bushes is to face upwards.
4. Hold your hand under the spacer and the bottom coupling bushes, and push the spacer carefully
into place.
5. Apply screw locking to the screws - LOCTITE type 242 is recommended as it allows dismantling
-and fit and fasten all the screws with the hand. It might be necessary to push the spacer a little
until the screws catch the thread and you feel that the spacer has found its right place.
6. Now tighten the screws with a torque wrench (5.3 kgm = 12 mm screws). As the shaft will rotate
during this operation it is necessary to "lock" the spacer by wedging a mandrel or a piece of flat
iron or the like in between the two following screw heads in order to lock the system while
tightening the screws.
7. When the coupling guard and the copper pipe to the rear cover have been fitted, and the
procedure in paragraph 6.1 has been followed, the pump is ready for start.

______________________________________________________________________________
DESMI Pumping Technology A/S 12
Tagholm 1
9400 Nørresundby –Denmark
Tel: [phone] Fax: [phone]
E-mail: [email protected] www.desmi.com
The fitting of the coupling in a compact pump is to be carried out just as carefully as described above,
but in a slightly different order:
Place the coupling bushes in the coupling half (861.2). The chamfering on the bushes is to face
downwards. Fit motor bracket and motor. Fit and fasten the screws (914.5) as described above. Fit
the copper pipe to manometers and rear cover. Fasten the coupling guard.
6.7 COUPLING GUARD
Protect the coupling guard against unintentional access to shaft and coupling. The pump must not be
started when the coupling guard (598.1) is dismantled. The coupling guard is either open below
(spacer design) or perforated (compact design) to allow inspection of leaks at the shaft seal.
7. FROST PROTECTION
Pumps which are not in operation during frost periods are to be drained to avoid frost damage.
Remove the plug at the bottom to emptythe pump. Alternatively, it is possible to use anti-freeze liquids
in normal constructions.
8. DISMANTLING
Before dismantling the pump make sure that it has stopped. Wiring to be dismantled by
skilled workmen. Then 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.
9. START-UP
A centrifugal pump will not function until it has been filled with liquid between the foot valve and up to
somewhat above the impeller.
The liquid also serves as coolant for the shaft seal. In order to protect the shaft seal the
pump must not run dry.
ATTENTION
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.

______________________________________________________________________________
DESMI Pumping Technology A/S 13
Tagholm 1
9400 Nørresundby –Denmark
Tel: [phone] Fax: [phone]
E-mail: [email protected] www.desmi.com
9.1 STARTING
On pumps not running the shaft shall be rotated (at least 2-3 revolutions) monthly to avoid standstill
damage to shaft seal and bearings. If the pump is filled with liquid it can alternatively be started up
shortly.
In special applications, it may require more frequent shaft rotation or start-up in order to avoid
seizing of the impeller and/or the shaft seal.
In pressurized systems the shaft seal often leaks a bit during standstill –in most cases the leakage
stops shortly after the pump is started up.
Before starting the pump check that
1. the shaft can rotate freely without jarring sounds.
2. pump and suction line are filled with liquid:
a. Pump with positive : Ventilate by means of the valve (741.1) of the rear cover.
suction lift
b. Pump with priming unit : Check that the priming continues until liquid comes out.
The above is important as the liquid serves as coolant for the shaft seal.
3. Start the pump for a moment to check the direction of rotation. If the direction is correct (i.e.
clockwise when viewed from above), the pump may be started.
NOTICE –for preventing premature failure of shaft seal and/or sliding bearing it is recommended:
- For pumps with bottom roller bearing: To run at least 300 rpm and use max. 1 minute on
acceleration from 0 to 300 rpm and max. 1 minute on deceleration from 300 to 0 rpm.
- For pumps with bottom sliding bearing: To run at least 500 rpm and use max. 1 minute
on
acceleration from 0 to 500 rpm and max. 1 minute on deceleration from 500 to 0 rpm.
Also pumps with bottom sliding bearing should not run with less than 0.5 bar differential
pressure.
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

______________________________________________________________________________
DESMI Pumping Technology A/S 14
Tagholm 1
9400 Nørresundby –Denmark
Tel: [phone] Fax: [phone]
E-mail: [email protected] www.desmi.com
the characteristics of the pump.
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.
10.1 FAULT-FINDING CHART
FAULT
CAUSE
REMEDY
The pump has no or
too low capacity
1. Wrong direction of
rotation
2. Piping system
choked
3. Pump choked
4. Suction line leaks/
Pump takes air
5. Suction lift too high
6. Pump and piping
system wrongly
dimensioned
7. The pump is not
ventilated
Change direction of
rotation to clockwise
when viewed from
above (the direction of
the arrow)
Clean or replace
Clean the pump
Find leakage, repair
the fault, non-return
valve not submerged
Check data sheet Q/H
curve and NPSH or
contact DESMI
As 5
Ventilate the pump

______________________________________________________________________________
DESMI Pumping Technology A/S 15
Tagholm 1
9400 Nørresundby –Denmark
Tel: [phone] Fax: [phone]
E-mail: [email protected] www.desmi.com
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 16
Tagholm 1
9400 Nørresundby –Denmark
Tel: [phone] Fax: [phone]
E-mail: [email protected] www.desmi.com
11. INSPECTION AND MAINTENANCE
11.1 INSPECTION DURING OPERATION
It is important to check at regular intervals that:
1. the pump pressure is as prescribed.
2. the pump does not vibrate, make noise or get hot.
3. there is no air in the pump.
4. no liquid is dripping from the drain holes for the shaft seals thus indicating leaks.
If one of the above points is not satisfactory, stop the pump and repair the fault.
11.2 DRAINING THE PUMP
When the piping system has been drained, note that there is still liquid left in the pump. Remove most
of the liquid by dismantling the pipe plug (912.1) at the bottom. Remove the remaining liquid by tilting
the pump casing (102.1) towards one of the flanges.
11.3 INSPECTION
- Before any inspection of the pump check that the unit cannot be started unintentionally.
- The system is to be without pressure and drained of liquid.
- The repairman must be familiar with the liquid which has been pumped as well as the safety
measures he is to take when handling the liquid.
When the pump has been dismantled check the following parts for wear and damage:
- Sealing ring/impeller : Wear=max. 1.5 mm diameter difference.
- Shaft seal : Check seat for flatness and cracks.
Check rubber parts for elasticity.
- Bearings : Slackness or noise.
- Coupling parts : Screws and coupling bushes, see paragraph 6.6.
- Pipes from pressure side
to top and bottom shaft
seal : Cleanness.
11.4 LUBRICATING BEARINGS
The top bearing is a closed ball bearing which does not need lubrication.
If the bottom bearing is a cylindrical roller bearing, then the lubricating procedure is as follows:
Pump without external grease kit:
1. Dismantle the bearing as described in paragraph 5.4.
2. Remove the old grease from bearing and bearing housing.
3. If the bearing has just been cleaned or if it is a new bearing, fill bearing completely and bearing
housing approx. 1/3 with grease.
4. Use a recommended lithium-based grease, see the table below.

______________________________________________________________________________
DESMI Pumping Technology A/S 17
Tagholm 1
9400 Nørresundby –Denmark
Tel: [phone] Fax: [phone]
E-mail: [email protected] www.desmi.com
Pump with external grease kit:
Later models of the DSL pumps with roller bottom bearing are equipped with external grease kit.
See drawing 405719 following.
On these pumps the bottom roller bearing shall be re-lubricated with 10 grams of grease every 5000
running hours through the external grease nipple mounted on the side of the pump casing.

______________________________________________________________________________
DESMI Pumping Technology A/S 18
Tagholm 1
9400 Nørresundby –Denmark
Tel: [phone] Fax: [phone]
E-mail: [email protected] www.desmi.com
Recommended types of grease:
ESSO
Beacon 2
BP
Energrease LS EP 2
Shell
Gadus S5 V100 2
Mobil
Mobil lux grease EP 2 and Mobil plex 47
Castrol
Spheerol AP 2
Texaco
Multifak EP 2
Q8
Rembrandt EP 2 and Rubens
Statoil
UniWay Li 62
5. The intervals between the lubrication of the bearings depend on the number of revolutions:
a. Pump with 4-pole motor: 5000 hours
b. Pump with 6-pole motor: 6000 hours
c. Pump with 8-pole motor: 7000 hours
If the pump is equipped with slide bearing, the bottom bearing needs no lubrication. The bearing is
lubricated and cooled by the liquid pumped via the pressure side of the pump.
12. REPAIRS
12.1 ORDERING SPARE PARTS
When ordering spare parts please always state pump type and serial No. See the name plate of the
pump and the spare parts drawing with item Nos. See assembly drawing.

______________________________________________________________________________
DESMI Pumping Technology A/S 19
Tagholm 1
9400 Nørresundby –Denmark
Tel: [phone] Fax: [phone]
E-mail: [email protected] www.desmi.com
13. OPERATING DATA
Type
Max. power consumption
KW
740/870/980/1170/ 1450 / 1750 rpm
Max. permissible
working pressure
(GG20 and RG5)
bar
Max. permissible
working pressure
(NiAlBz and ductile iron GGG40)
bar
DSL 300-320
- / - / 30 / 50 / 95 / 165
5
10
DSL 400-430
92 / 150 / 215 / 365 / - / -
5
8
DSL 400-495
92 / 150 / 215 / 365 / - / -
5
8
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 20
Tagholm 1
9400 Nørresundby –Denmark
Tel: [phone] Fax: [phone]
E-mail: [email protected] www.desmi.com
14. EU DECLARATION OF CONFORMITY
DESMI PUMPING TECHNOLOGY A/S, hereby declare that our pumps of the type DSL 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. Safetydistancesto 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, March 05 2019
Henrik Mørkholt Sørensen
Managing Director
DESMI Pumping Technology A/S
Tagholm 1
9400 Nørresundby