Desmi NSA Series Troubleshooting guide

OPERATION AND MAINTENANCE INSTRUCTIONS
DESMI self-priming centrifugal pump
TYPE NSA
DESMI Pumping Technology A/S
Tagholm 1 –DK-9400 Nørresundby –Denmark
Tel.:
[phone]
Fax:
[phone]
E-mail:
[email protected]
Internet:
www.desmi.com
Manual:
T1493
Language:
English
Revision:
E (11/19)
Special pump No. ................................................

Table of contents:
1. PRODUCT DESCRIPTION ......................................................................................................................3
1.1 DELIVERY.................................................................................................................................................3
2. TECHNICAL DATA...................................................................................................................................3
2.1 EXPLANATION OF THE TYPE NUMBER ............................................................................................3
2.2 TECHNICAL DESCRIPTION..................................................................................................................4
3 . INSTALLATION.......................................................................................................................................5
3.1 MOUNTING/FASTENING .......................................................................................................................5
3.2WIRING......................................................................................................................................................5
4. TRANSPORT/ STORAGE........................................................................................................................6
5. INSPECTING THE PUMP ........................................................................................................................7
5.1 INSPECTION.............................................................................................................................................7
5.2 FITTING SHAFT ....................................................................................................................................... 7
5.3 FITTING SHAFT SEAL ............................................................................................................................7
5.4 ALIGNING COUPLING............................................................................................................................7
6. FROST PROTECTION .............................................................................................................................8
7. DISMANTLING..........................................................................................................................................8
8. START-UP.................................................................................................................................................9
8.1 STARTING................................................................................................................................................. 9
9. SYSTEM BALANCING.............................................................................................................................9
10. INSPECTION AND MAINTENANCE ..................................................................................................11
10.1 DRAINING THE PUMP........................................................................................................................12
10.2 BEARINGS............................................................................................................................................12
11. REPAIRS - ORDERING SPARE PARTS ...........................................................................................12
12. OPERATING DATA..............................................................................................................................12
13. EU DECLARATION OF CONFORMITY .............................................................................................13
14. INFORMATION RELEVANT FOR DISASSEMBLY OR DISPOSAL AT END-OF-LIFE................14
15. ASSEMBLY DRAWINGS AND SPARE PARTS LISTS....................................................................15
15.1 ASSEMBLY DRAWING NSA50-200/zz-M12.............................................................................. 15
15.2 ASSEMBLY DRAWING NSA80-250/zz-M12.............................................................................. 16
15.3 ASSEMBLY DRAWING NSA80-250/zz-M09.............................................................................. 17

DESMI Pumping Technology A/S 3
Tagholm 1
9400 Nørresundby –Dänemark
Tlf. nr.: [phone]
Fax [phone]
E-mail: [e-mail] www.desmi.com
1. PRODUCT DESCRIPTION
These operation and maintenance instructions apply to the DESMI NSA-pump series. The
pumps are available in the sizes DN50 and DN80 discharge.
DESMI NSA is a single-stage self-priming centrifugal pump with stainless steel shaft, and
mechanical shaft seal. The NSA-pump is further equipped with a semi-open impeller, which
does not choke as
easily as a closed impeller.
The pump is suited for clean and polluted liquids with temperatures between 0 and 80C. With
special shaft seal up to 140C.
The suction branch of the pump is mounted well above impeller inlet. This is an advantage as
the pump will not - in case of a clack flap leakage - loose all the priming water and
consequently the priming ability.
As the pump is self-priming, contrary to ordinary centrifugal pumps it will resume pumping if,
for a short moment, the liquid has been lowered to a level below the suction pipe.
The pump is particularly suitable for the pumping of water in connection with e.g. cooling of
diesel engines, as bilge pump, ballast pump, irrigation, washing plants, air conditioning,
cooling systems, and sanitary systems, etc. Furthermore, in the majority of cases where the
transport of liquid is required within industry.
1.1 DELIVERY
- Check on receipt that the delivery 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
The pumps are manufactured in various material combinations which appear from the type
number on the name plate. See below.
2.1 EXPLANATION OF THE TYPE NUMBER
All the NSA-pumps are provided with a name plate. The type number indicated on the name
plate is built up as follows:
NSAXXX-YYYB/ZZ-MR/O
XXX : Discharge flange diameter.
YYY : Standard impeller diameter.
B : If mounted with special impeller for 2-pole motor
ZZ : Height of the impeller blades.
M : The material combination of the pump.
R : The assembly combination of the pump.
O : Actual impeller diameter.

DESMI Pumping Technology A/S 4
Tagholm 1
9400 Nørresundby –Dänemark
Tlf. nr.: [phone]
Fax [phone]
E-mail: [e-mail] www.desmi.com
M may be the following:
A : Standard. casing: GG20. Impeller/wear plate: RG5.
B : Standard. casing: GG20. Impeller/wear plate: Stainless steel.
C : All cast iron.
D : Casing: RG5. Impeller/wear plate: RG5.
E : Special bronze casing and/or impeller
The pumps are available in other material combinations at request.
R may be the following:
07 : Mounted on base frame with petrol or diesel engine, or with
hydraulic or electric motor.
09 : With bare shaft end.
12 : Flange-mounted with electric motor.
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.
Pumps in material combinations A and C are primarily used for freshwater.
Pumps in material combination D are primarily used for seawater.
If the pumps are designed for special purposes the following is to be indicated:
Pump No. :
Pump type :
Application :
Comment :
2.2 TECHNICAL DESCRIPTION
The noise level from 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).
The noise level of the motor appears from the instruction manual for the motor.
The pump capacity appears on the nameplate 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.
The permissible loads on the flanges are indicated in the following table:
Pump
Fv (N)
Fh (N)
F (N)
Mt (Nm)
NSA-50-200
1250
950
1550
170
NSA-80-250
1450
1050
1800
270

DESMI Pumping Technology A/S 5
Tagholm 1
9400 Nørresundby –Dänemark
Tlf. nr.: [phone]
Fax [phone]
E-mail: [e-mail] www.desmi.com
Fv : The max. permissible sum of the vertical forces on the two flanges.
Fh : The max. permissible sum of the horizontal forces on the two flanges.
F : The vectorial sum of the two forces Fv and Fh.
Mt : The max. permissible sum of the torches on the two flanges.
In connection with the permissible loads on the flanges the following is to be observed:
where index "calc" is the values calculated by the user.
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. Check that the centre line of the shaft is horizontal.
The max. permissible loads on the flanges stated in paragraph 2.2. are to be observed.
The suction line to the pump is to be mounted carefully, so that it is absolutely tight, as even
minor 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 height of the
impeller blades of the pump in question.
The pipes are to be arranged in such a way that stresses resulting from fluctuations in
temperature will not have any effect on the pump. Because of the 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 through a flexible coupling, motor and coupling are to be placed on a
common base plate. In this connection the following must be observed:
- Avoid distortion of the base plate.
- Avoid distortion of the piping system.
- Check carefully that pump and motor are accurately aligned.
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.
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
OF June 14, 1989, on the safety of machines.
3.2WIRING
Wiring to be carried out by authorised skilled workmen according to the rules and
regulations in force.
2
22






















t
calccalc M
M
F
F

DESMI Pumping Technology A/S 6
Tagholm 1
9400 Nørresundby –Dänemark
Tlf. nr.: [phone]
Fax [phone]
E-mail: [e-mail] www.desmi.com
4. TRANSPORT/ STORAGE
The weights of the pumps without motor are stated in the following table:
Pump
Weight kg
Pump
Weight kg
NSA50-200/zz-A12
60
NSA80-250/zz-A12
95
NSA50-200/zz-D12
60
NSA80-250/zz-D12
105
NSA80-250/zz-A09
92
NSA80-250/zz-D09
102
Lift the pump by placing the rope around it and see to it that the pump is balanced.
The rope must not bear against sharp edges and corners.
Lifting eyes might be mounted in the pump and used instead. The pump weights appear
from the above table.
Before shipment the pump is to be fastened securely on a pallet or the like.
The pump is to be stored in a dry area.

DESMI Pumping Technology A/S 7
Tagholm 1
9400 Nørresundby –Dänemark
Tlf. nr.: [phone]
Fax [phone]
E-mail: [e-mail] www.desmi.com
5. INSPECTING THE PUMP
5.1 INSPECTION
When the pump has been dismantled, check the following parts for wear and damage:
- Wear plate/impeller : Max. clearance 0.4 - 0.5 mm.
- Shaft seal/rear cover : Check seat for flatness and cracks.
Check rubber parts for elasticity.
- Bearings : Replace in case of wear and noise.
5.2 FITTING SHAFT
When the pump has been assembled, check that the shaft rotates freely. In case the shaft
has been dismantled in the 12-combination, adjust the shaft to the original, axial position on
the electric motor to obtain a 0,2-0,5 mm gap between impeller and wear plate. Fasten the
pointed screws (if three screws first the middle screw) according to the below table –screws
to be secured with Loctite 243 or Omnifit 40M or similar. Check that the wobble, measured
as close to the shaft end as possible, is within the limits indicated in the table.
Motor size
Torque
Pointed screws
Max. wobble
100/112
10 Nm
70 μm
132
24 Nm
70 μm
5.3 FITTING SHAFT SEAL
Before fitting the seat, clean the recess in the shaft seal cover. When fitting the seat, remove
the protective coating 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 surface of the slide ring rubber bellows
with soapy water and push it over the shaft. The use of a conical fitting bush as shown on
the 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 soapy water 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 there are no leaks.
5.4 ALIGNING COUPLING
In order to avoid break-downs of a pump coupled to a motor on the same base plate through
a flexible coupling, the following should be observed:

DESMI Pumping Technology A/S 8
Tagholm 1
9400 Nørresundby –Dänemark
Tlf. nr.: [phone]
Fax [phone]
E-mail: [e-mail] www.desmi.com
1. Avoid distortion of the base plate.
2. Avoid distortion in the piping system.
3. Check on the coupling that pump and motor are aligned accurately.
Below please find 2 proposals for alignment. The deviations mentioned cover a complete
revolution of the coupling. The distance between the coupling halves is to be between 2 and
4 mm.
* : Steel ruler.
** : Thickness gauge.
6. 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 empty the pump. Alternatively, it is possible to use anti-
freeze liquids in normal constructions.
7. 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 beenpumping
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.

DESMI Pumping Technology A/S 9
Tagholm 1
9400 Nørresundby –Dänemark
Tlf. nr.: [phone]
Fax [phone]
E-mail: [e-mail] www.desmi.com
8. START-UP
A self-priming centrifugal pump will not function until the pump casing
has been filled with liquid. Remove the plug at the top of
the pump casing andfill the pump with cold liquid. Fit the
plug and the pump is ready for service.The liquid also
serves as coolant for the shaft seal. Consequently, the
pump must in no circumstances be started before it has
been primed with liquid. Furthermore, the pump must
never 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.
The pump is equipped with a relief valve, which opens at a pre-set pressure. Be careful: If
the valve opens, the escaping liquid will most likely be hot. The relief valve must in NO
circumstances be removed or re-adjusted !
As regards maintenance of the relief valve - see paragraph 10.
8.1 STARTING
Before starting the pump check that
- the shaft rotates freely without jarring sounds.
- the pump casing is filled with liquid.
Start the pump for a moment to check the direction of rotation. If the direction is correct (i.e.
in the direction of the arrow), the pump may be started.
9. 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.
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 –Dänemark
Tlf. nr.: [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
pump/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 dimensioning/
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
7. RPM too low
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
Electric motor running on two
phases or lower frequency?

DESMI Pumping Technology A/S 11
Tagholm 1
9400 Nørresundby –Dänemark
Tlf. nr.: [phone]
Fax [phone]
E-mail: [e-mail] www.desmi.com
FAULT
CAUSE
REMEDY
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
5. RPM too high
6. Pump and electric
motor not aligned.
Insert orifice plate or check
valve/Contact DESMI
Contact DESMI
Dismantle the pump, remove
the cause
Check fuses, cable
connection, and cable
Frequency too high.
Align unit (see para. about
alignment)
The pump capacity is
unstable
1. Suction line leaks
2. Air pockets in suction
line
3. The pump takes air
Tighten suction line
Normally they disappear in a
short time
Liquid reservoir emptied/
Suction line not sufficiently
submerged
The pump makes
noise
1. Cavitation in pump
2. Incorrect alignment
3. Defective bearings
Suction lift too high/ Suction
line wrongly dimensioned/
liquid temperature too high.
Align the pump and motor
(see para. about alignment)
Replace bearings
10. INSPECTION AND MAINTENANCE
- 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 type of liquid, which has been pumped as well
as with the safety measures he is to take when handling the liquid.
- Inspect the shaft seal for leaks at regular intervals.
- Activate the relief valve at regular intervals in order to check the function. If the valve is
choked, replace or clean it, if possible.

DESMI Pumping Technology A/S 12
Tagholm 1
9400 Nørresundby –Dänemark
Tlf. nr.: [phone]
Fax [phone]
E-mail: [e-mail] www.desmi.com
10.1 DRAINING THE PUMP
When the piping system has been drained, note that there is still some liquid left in the
pump. Remove the remaining liquid by dismantling the pipe plug at the bottom of the pump.
10.2 BEARINGS
The pump (09 design only) is equipped with ball bearings, which were lubricated for life
before leaving the factory. Therefore, they require no attention but are to be replaced in case
of noise or bearing wear. Place a bead of grease on the sides of cleaned or newly mounted
bearings. As far as semi-closed bearings are concerned, place grease on the open side of
the bearing only.
A recommended grease quality on a lithium-basis is used:
ESSO.................................................Beacon 2
BP......................................................Energrease EP grease 2
Shell...................................................Alvania grease 2
Mobil ..................................................Mobil lux grease EP 2 or Mobil plex 47
Castrol................................................Spherol AP2
Texaco...............................................Multifak EP 2
Q8......................................................Rembrandt EP 2 and Rubens
Statoil.................................................Statoil Uniway U2
11. REPAIRS -ORDERING SPARE PARTS
When ordering spare parts please always state pump type and pump No. (appears on the
name plate of the pump). See also spare parts drawing with item Nos.
12. OPERATING DATA
The following working pressures are allowed:
PUMP
NSA50-200
NSA80-250
PRESSU
RE [bar]
8
12
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.
The following max. numbers of revolutions are allowed for NSA-pumps with full impeller
diameter:
Pump
Max. number of
revolutions
Pump
Max. number of
revolutions
NSA50-200
3000 RPM
NSA80-250
3000 RPM
The capacities of the pumps appear from the nameplates.

DESMI Pumping Technology A/S 13
Tagholm 1
9400 Nørresundby –Dänemark
Tlf. nr.: [phone]
Fax [phone]
E-mail: [e-mail] www.desmi.com
13. EU DECLARATION OF CONFORMITY
DESMI PUMPING TECHNOLOGY A/S, hereby declare that our pumps of the type NSA 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

DESMI Pumping Technology A/S 14
Tagholm 1
9400 Nørresundby –Dänemark
Tlf. nr.: [phone]
Fax [phone]
E-mail: [e-mail] www.desmi.com
14.INFORMATION RELEVANT FOR DISASSEMBLY OR DISPOSAL AT END-OF-
LIFE
No damage materials are used in DESMI pumps –please refer to DESMI Green Passport
(can be sent on request –contact a DESMI sales office) –i.e. common recycling companies
can handle the disposal at end-of-life. Alternatively the pump and motor can be returned to
DESMI at end-of-life for safe recycling.

DESMI Pumping Technology A/S 15
Tagholm 1
9400 Nørresundby –Dänemark
Tlf. nr.: [phone]
Fax [phone]
E-mail: [e-mail] www.desmi.com
15.ASSEMBLY DRAWINGS AND SPARE PARTS LISTS
15.1 ASSEMBLY DRAWING NSA50-200/zz-M12
1 Nut
2 Stud
3 Sealing washer
5 Impeller
6 O-ring
8 Washer
9 Nut
10 Wear plate
11 Pump casing
12 Stud
13 Plug/sealing
washer
14 Relief valve
17 Shaft/Pointed
screw
19 Motor bracket
20 Name plate
21 Screw for
nameplate
22 Nut
29 Key
30 Stud
31 Screw/washer
33 Plug/sealing
washer
37 Shaft seal
38 Check valve

DESMI Pumping Technology A/S 16
Tagholm 1
9400 Nørresundby –Dänemark
Tlf. nr.: [phone]
Fax [phone]
E-mail: [e-mail] www.desmi.com
15.2 ASSEMBLY DRAWING NSA80-250/zz-M12
1 Pump
casing
2 Motor bracket
4 Rear cover
6 Pointed screw
7 Impeller
8 Wear plate
9 Set screw
10 Washer
15 Shaft
16 Key
17 Intermediate flange*
18 Spring washer
19 Stud
20 Stud
21 Stud
22 Stud
24 Pointed screw
25 Nut
26 Nut
27 Washer
28 Pipe plug
29 Pipe plug
30 Inlet flange
31 Screw/washer
32 Allen screw**
37 Shaft seal
38 Check valve
41 O-ring
44 Sealing washer
46 Sealing washer
75 Pipe plug
76 Relief valve
*) Only for size 132
motor
**) If B5 motor

DESMI Pumping Technology A/S 17
Tagholm 1
9400 Nørresundby –Dänemark
Tlf. nr.: [phone]
Fax [phone]
E-mail: [e-mail] www.desmi.com
15.3 ASSEMBLY DRAWING NSA80-250/zz-M09
1
Pump casing
17
Key
29
Pipe plug
2
Bearing housing
18
Spring washer
30
Inlet flange
4
Rear cover
19
Stud
31
Bearing
5
Cover under
bearing
20
Stud
32
Bearing
6
Lock ring
21
Stud
37
Shaft seal
7
Impeller
22
Stud
38
Check valve
8
Wear ring
23
Pointed screw
39
V-ring
9
Set screw
24
Support washer
41
O-ring
10
Washer
25
Nut
44
Sealing washer
11
Set screw
26
Nut
46
Sealing washer
15
Shaft
27
Washer
75
Pipe plug
16
Key
28
Pipe plug
76
Relief valve