Wilo NPG Series User manual

GBInstallation and operating instructions
Wilo-NPG
4095556/Ed_01_gb_0610_Wilo
ООО "ПромХимТех" - официальный поставщик насосов NL / NLG / NPG вРоссии иСНГ
www.promhimtech.ru / [email protected]

English
Installation and maintenance instructions Wilo-Horizontal pumps NPG
1 Introduction and Safety
1.1 General
These instructions must always be kept close to
the product's operating location or directly with
the product.
These instructions are intended to facilitate fami-
liarization with the product and its permitted use.
Operating the product in compliance with these
instructions is important to help ensure reliability
in service and avoid risks. The instructions may not
take into account local regulations; ensure such
regulations are observed by all, including those
installing the product. Always coordinate repair
activity with operations personnel, and follow all
plant safety requirements and applicable safety
and health laws and regulations.
These instructions should be read prior to
installing, operating, using and maintaining the
equipment in any region worldwide. The equip-
ment must not be put into service until all the
conditions relating to safety noted in the
instructions, have been met.
1.2 CE marking and approvals
It is a legal requirement that machinery and equip-
ment put into service within certain regions of the
world shall conform with the applicable
CE Marking Directives covering Machinery and,
where applicable, Low Voltage Equipment, Elec-
tromagnetic Compatibility (EMC), Pressure Equip-
ment Directive (PED).
Where applicable the Directives and any additional
Approvals cover important safety aspects relating
to machinery and equipment and the satisfactory
provision of technical documents and safety
instructions. Where applicable this document
incorporates information relevant to these Direc-
tives and Approvals.
To confirm the Approvals applying and if the pro-
duct is CE marked, check the serial number plate
markings and the Certification. (See section 9,
Certification.)
1.3 Disclaimer
Information in these User Instructions is belie-
ved to be reliable. In spite of all the efforts to
provide sound and all necessary information the
content of this manual may appear insufficient
and we don’t guarantee as to its completeness
or accuracy.
We manufacture products to exacting Internatio-
nal Quality Management System Standards as cer-
tified and audited by external Quality Assurance
organizations. Genuine parts and accessories have
been designed, tested and incorporated into the
products to help ensure their continued product
quality and performance in use.
Damage or failure caused by misuse is not covered
by the warranty. In addition, any modification of
products or removal of original components may
impair the safety of these products in their use.
1.4 Copyright
All rights reserved. No part of these instructions
may be reproduced, stored in a retrieval system or
transmitted in any form or by any means without
prior permission.
1.5 Duty conditions
The product must not be operated beyond the
parameters specified for the application. If there
is any doubt as to the suitability of the product
for the application intended, contact us for
advice, quoting the serial number.
If the conditions of service on your purchase order
are going to be changed (for example liquid pum-
ped, temperature or duty) it is requested that the
user seeks the written agreement of the company
before start up.
1.6 Safety
1.6.1 Summary of safety markings
These User Instructions contain specific safety
markings where non-observance of an instruction
would cause hazards. The specific safety markings
are:
This symbol indicates electrical safety instructions
where non-compliance will involve a high risk to
personal safety or the loss of life.
This symbol indicates safety instructions where
non-compliance would affect personal safety and
could result in loss of life.
This symbol indicates “hazardous and toxic fluid”
safety instructions where non-compliance would
affect personal safety and could result in loss of
life.
1.6.2 Personnel qualification and training
All personnel involved in the operation, installa-
tion, inspection and maintenance of the unit must
be qualified to carry out the work involved. If the
personnel in question do not already possess the
necessary knowledge and skill, appropriate trai-
ning and instruction must be provided.
This symbol indicates safety instructions
where non-compliance will involve some
risk to safe operation and personal safety
and would damage the equipment or pro-
perty.
This sign is not a safety symbol but indica-
tes an important instruction in the assem-
bly process.
CAUTION!
NOTE:

English
6Wilo AG 09/2005
1.6.3 Safety action
This is a summary of conditions and actions to
prevent injury to personnel and damage to the
environment and to equipment.
NEVER DO MAINTENANCE WORK WHEN THE
UNIT IS CONNECTED TO POWER
GUARDS MUST NOT BE REMOVED WHILE THE
PUMP IS OPERATIONAL
DRAIN THE PUMP AND ISOLATE PIPEWORK
BEFORE DISMANTLING THE PUMP
The appropriate safety precautions should be
taken where the pumped liquids are hazardous.
HANDLING COMPONENTS
Many precision parts have sharp corners and the
wearing of appropriate safety gloves and equip-
ment is required when handling these compon-
ents. To lift heavy pieces above 25 kg (55 lb) use
a crane appropriate for the mass and in accor-
dance with current local regulations.
THERMAL SHOCK
Rapid changes in the temperature of the liquid
within the pump can cause thermal shock, which
can result in damage or breakage of components
and should be avoided.
NEVER APPLY HEAT TO REMOVE IMPELLER
Trapped lubricant or vapour could cause an
explosion.
HOT (and cold) PARTS
If hot or freezing components or auxiliary hea-
ting supplies can present a danger to operators
and persons entering the immediate area action
must be taken to avoid accidental contact. If
complete protection is not possible, the
machine access must be limited to maintenance
staff only, with clear visual warnings and indica-
tors to those entering the immediate area. Note:
bearing housings must not be insulated and
drive motors and bearings may be hot.
If the temperature is greater than 68 °C (175 °F)
or below 5 °C (20 °F) in a restricted zone, or
exceeds local regulations, action as above shall
be taken.
HAZARDOUS LIQUIDS
When the pump is handling hazardous liquids
care must be taken to avoid exposure to the
liquid by appropriate sitting of the pump, limi-
ting personnel access and by operator training.
If the liquid is flammable and/or explosive, strict
safety procedures must be applied.
Gland packing must not be used when pumping
hazardous liquids.
1.7 Noise level
When pump noise level exceeds 85-dBA attention
must be given to prevailing Health and Safety
Legislation, to limit the exposure of plant opera-
ting personnel to the noise. The usual approach is
to control exposure time to the noise or to enclose
the machine to reduce emitted sound. You may
have already specified a limiting noise level when
the equipment was ordered, however if no noise
requirements were defined then machines above
a certain power level will exceed 85 dBA. In such
situations consideration must be given to the fit-
ting of an acoustic enclosure to meet local regula-
tions.
Pump noise level is dependent on a number of
factors - the type of motor fitted, the operating
capacity, pipework design and acoustic characte-
ristics of the building.
The figures in the table below are indicative only,
PREVENT EXCESSIVE EXTERNAL PIPE
LOAD
Do not use pump as a support for piping.
Do not mount expansion joints, so that
their force, due to internal pressure, acts
on the pump flange.
ENSURE CORRECT LUBRICATION
(See section 5, Commissioning, startup,
operation and shutdown.)
START THE PUMP WITH OUTLET VALVE
PARTLY OPENED
(Unless otherwise instructed at a speci-
fic point in the User Instructions.)
This is recommended to minimize the
risk of overloading and damaging the
pump motor at full or zero flow. Pumps
may be started with the valve further
open only on installations where this
situation cannot occur. The pump outlet
control valve may need to be adjusted to
comply with the duty following the run-
up process. (See section 5, Commissio-
ning start-up, operation and shutdown.)
NEVER RUN THE PUMP DRY
INLET VALVES TO BE FULLY OPEN WHEN
PUMP IS RUNNING
Running the pump at zero flow or below
the recommended minimum flow conti-
nuously will cause damage to the seal.
DO NOT RUN THE PUMP AT ABNOR-
MALLY HIGH OR LOW FLOW RATES
Operating at a flow rate higher than nor-
mal or at a flow rate with no backpres-
sure on the pump may overload the
motor and cause cavitations. Low flow
rates may cause a reduction in pump/
bearing life, overheating of the pump,
instability and cavitations/vibration.
CAUTION!
CAUTION!
CAUTION!
CAUTION!
CAUTION!
CAUTION!

English
Installation and maintenance instructions Wilo-Horizontal pumps NPG
they are subject to a +3 dB tolerance, and cannot
be guaranteed.
The values are based on the noisiest ungeared
electric motors which are likely to be encountered.
They represent Sound Pressure Levels at 1 m
(3.3 ft) from the directly driven pump, for "free
field over a reflecting plane".
If a pump only has been purchased, for fitting with
your own driver, then the "pump only" noise levels
from the table should be combined with the level
for the driver obtained from the supplier. If the
motor is driven by an inverter, it may show an
increase in noise level at some speeds. Consult a
Noise Specialist for the combined calculation.
In areas where the staff has to intervene, remem-
ber that when the level of the sound pressure is:
Below 70 dBA:
It is not necessary to take special precautions.
Above 70 dBA:
People working continuously in the machine room
must be supplied with protective devices against
noise.
Below 85 dBA :
No particular measures need to be taken for casual
visitors staying in the room during a limited period.
Above 85 dBA:
The room must be considered as a dangerous area
because of the noise and a warning sign must be
fixed at each entry warning the people coming
into the room, even for a short period, that they
must wear hearing protection.
Above 105 dBA:
Special hearing protection adapted to this noise
level and to the spectral noise components must
be installed and a warning sign to this effect erec-
ted at each entry. The staff in the room must
wear ear protection.
Make sure that the noise, which travels through
the walls and windows, does not generate too
high noise levels in the machine room's surroun-
dings.
2 Transport and storage
2.1 Consignment receipt and unpacking
Immediately after receipt of the equipment it
must be checked against the delivery and shipping
documents for its completeness and that there
has been no damage in transportation.
Any shortage and or damage must be reported
immediately and received in writing within one
month of receipt of the equipment. Later claims
cannot be accepted.
Check any crate, boxes and wrappings for any
accessories or spare parts that may be packed
separately with the equipment or attached to
Typical sound pressure level,
dBA, LpA at 1 m reference 20 PPa (LwA sound power1 pW where LpA >85dBA)
Motor size and speed 3550 r/min 2900 r/min 1750 r/min 1450 r/min
Pumpand
motor
Pump
only
Pump and
motor
Pump
only
Pumpand
motor
Pump
only
Pumpand
motor
Pump
only
kW (hp) dBA dBA dBA dBA dBA dBA dBA dBA
<0.55 (<0.75) 71 66 64 62 64 62 63 62
0.75(1) 7466676267626362
1.1 (1.5) 74 68 67 64 67 64 65 64
1.5 (2) 77 70 70 66 70 66 66 66
2.2 (3) 78 72 71 68 71 68 68 68
3 (4) 81 74 74 70 74 70 70 70
4 (5) 82 75 75 71 75 71 71 71
5.5 (7.5) 90 (99) 77 83 73 76 73 72 71
7.5 (10) 90 (99) 78 83 74 77 74 73 72
11 (15) 91 (100) 80 84 76 78 76 74 73
15 (20) 92 (101) 83 85 (94) 79 80 79 76 75
18.5 (25) 92 (101) 83 85 (94) 79 80 79 76 75
22 (30) 92 (101) 83 85 (94) 79 81 79 77 75
30 (40) 100 (109) 85 (94) 93 (102) 81 84 80 80 76
37 (50) 100 (109) 86 (95) 93 (102) 82 84 80 80 76
45 (60) 100 (109) 87 (96) 93 (102) 83 84 80 80 76
55 (75) 100 (109) 88 (97) 95 (104) 84 86 (95) 81 82 77
75 (100) 100 (109) 90 (99) 95 (104) 86 (95) 88 (97) 81 83 78
90 (120) 100 (109) 90 (99) 95 (104) 86 (95) 90 (99) 81 85 (94) 78
110 (150) 100 (109) 91 (100) 95 (104) 87 (96) 91 (100) 83 86 (95) 79
150 (200) 101 (110) 92 (101) 96 (105) 88 (97) 91 (100) 83 86 (95) 79

English
8Wilo AG 09/2005
sidewalls of the box or equipment.
Each product has a unique serial number. Check
that this number corresponds with that advised
and always quote this number in correspondence
as well as when ordering spare parts or further
accessories.
2.2 Handling
2.2.1 General instructions concerning handling
Boxes, crates, pallets or cartons may be unloaded
using forklift vehicles or slings dependent on their
size and construction. See 2.3.1 for positioning of
slings.
To lift heavy pieces above 25 kg (55 lb), use a
winch adapted to the mass and in accordance with
the current local regulations.
To lift machines or pieces with one or several sus-
pension rings, only use hooks and chains in com-
pliance with the local regulations concerning
safety. Never put cables, chains or ropes directly
on or in the suspension rings. Cables, chains or lif-
ting ropes must never present excessive bending.
Never bend the lifting hooks, suspension rings,
chains, etc., which should only be made to endure
stresses within, calculated limits. Remember that
the capacity of a lifting device decreases when the
direction of the lifting force direction makes an
angle with the device axis.
To increase the safety and the efficiency of the lif-
ting device, all the lifting elements must be as
perpendicular as possible. If necessary a lifting
beam can be placed between the winch and the
load.
When heavy pieces are lifted up, never stay or
work under the load or in the area, which could be
in the path of the load if it were to swing or fall
away. Never leave a load hanging from a winch.
The acceleration or the slowing-down of lifting
equipment must stay in the safety limits for the
staff.
A winch must be positioned in such a way that the
load will be raised perpendicularly. Where possible
necessary precautions must be taken to avoid the
swing of the load, using for example two winches
making approximately the same angle, below 30°,
with the vertical.
2.2.2 Pump masses
All motors (for masses see the motor description
plate) must be handled with a winch.
For masses above 25 kg (55 lb), manual handling
is forbidden.
2.3 Lifting
2.3.1 Slinging of motor pumps units
Use handling means in accordance with motor
pump unit mass mentioned on the CE plate. For
the masses of the pumps bare end of shaft see
table § 2.2.2 and nameplate.
Pump type Pump mass (kg)
NPG65 – 315 140
NPG100 – 315 160
NPG150 - 200 130
NPG150 - 500 475
NPG200 - 250 175
NPG200 - 315 260
NPG200 - 355 265
NPG200 - 400 370
NPG200 - 500 420
NPG250 - 250 290
NPG250 - 315 330
NPG250 - 355 370
NPG250- -400 415
NPG250 - 500 500
NPG300 - 300 370
NPG300 - 400 480
NPG300 - 450 550
NPG300 - 500 710
NPG350 - 350 700
NPG400 - 500 1100
NPG400 - 650 1250
NPG500 - 500 1450
To avoid distortion, the pump unit
should be lifted as shown.
Motor pump unit
CAUTION!

English
Installation and maintenance instructions Wilo-Horizontal pumps NPG
When handling always wear gloves, safety boots
and an industrial safety helmet.
For masses above 25 kg (55 lb), manual handling
is forbidden.
2.4 Storage
Do not store pumps starting on the fan guard.
The pump may be stored as above for up to 6
months. Consult us for preservative actions when
a longer storage period is needed.
2.5 Recycling and end of product life
At the end of the service life of the product or its
parts, the relevant materials and parts should be
recycled or disposed of using an environmentally
acceptable method and local regulations. If the
product contains substances that are harmful to
the environment, these should be removed and
disposed of in accordance with current regulati-
ons. This also includes the liquids and or gases that
may be used in the "seal system" or other utilities.
Make sure that hazardous substances are dis-
posed of safely and that the correct personal
protective equipment is used. The safety speci-
fications must be in accordance with the current
regulations at all times.
3 Pump Description
3.1 Configurations
The centrifugal motor pump unit is designed for
the pumping of cold water or all clear liquids which
are not solid and liquid mixtures, corrosive, abra-
sive or explosive when in contact with the pump
motor unit and its working parts (Important: for
other liquids consult us for preliminary advice).
The NPGtype pump is a single-stage pump with
axial suction, support under pump casing (Stan-
dard NF EN 733) and tangential vertical discharge.
The pumps of this range allow to the removal of
the pump rotor whilst leaving the pump casing
connected to the suction and discharge pipework.
The pump must be stored in a non-explosive,
ventilated location, sheltered from bad weather,
dust and vibrations.
The reliability of the delivered machine can only
be ensured if it is used according to the conditions
given in this manual. The maximum values speci-
fied in this manual must never be exceeded..
Bareshaft pump
Store the pump in a clean, dry location
away from vibration. Leave piping con-
nection covers in place to keep dirt and
other foreign material out of pump
casing. Turn pump at intervals to pre-
vent brinelling of the bearings and the
seal faces, if fitted, from sticking.
CAUTION!
Maximum working pressure at suc-
tion:
in the limit of the
maximum working
pressure at discharge
for zero flow accor-
ding to the pump
type
Maximum pumped fluid temperature
• Gland packing without cooling: d105 °C
• Mechanical seal without cooling:
•ACSversion d80 °C
• Standard version d140 °C
Maximum solid suspension 50 g/m3
Density 1
Viscosity 1
Frequency 50 Hz
Maximum speed
• for all pumps exept 1450 min-1
•forNPG400-500, NPG400-650,
NPG500-500
990 min-1
•forNPG65-315 , NPG100-315 2900 min-1

English
10 Wilo AG 09/2005
3.2 Nomenclature
Designation of pump:
Each pump is supplied with the following name-
plate:
4Installation
4.1 Location
The pump should be located to allow room for
access, ventilation, maintenance and inspection
with ample headroom for lifting and should be as
close as practicable to the supply of liquid to be
pumped.
Maximum effective pressure at discharge in bar
NPG(cast iron EN-GJL-250) - PN 10 NPG(cast iron EN GJS-400-15) - PN 16 - PN 10

Impeller
DN
150
DN
200
DN
250
DN
300
DN
350
DN
400
DN
500
DN
150
DN
200
DN
250
DN
300
DN
350
DN
400
DN
500
200 4 6
250 4 4 6 6
300 4 6
315 8 8 12 12
350 4 6
355 8 8 12 12
400 8 8 8 12 12 12
450 8 12
500 16 10 10 10 6.5 4 15 15 15 10 6
650 6.5 10
NPG200 / 315 - 37 / 4-12 - ...
NPGType of pump WILO
200 Nominal width of pipe mount
315 Diameter of impeller
37 Power of motor
4 2 or 4 poles motor
12 05 Mechanical seal-standard coupling
12 Mechanical seal-coupling with
spacer
01 Packing gland-standard coupling
02 Packing gland-coupling with spacer
XX Other design
... Options
Nameplate
1 Type of pump
2 Flow rate
3Head
4 Date of construction and article number
5 Diameter of impeller
6 Speed of rotation
7Mass
8 Maximum admissible pressure at 20 °C
9 Maxi/Mini temperature
10 Radial/Thrust bearing
1
2
3
4
5
6
7
8
9
10

English
Installation and maintenance instructions Wilo-Horizontal pumps NPG
4.2 Foundation
The base plate should be mounted onto a firm
foundation, either an appropriate thickness of
quality concrete or sturdy steel framework. It
should NOT be distorted or pulled down onto the
surface of the foundation, but should be suppor-
ted to maintain the original alignment.
Anchor bolts must be in accordance with the foot
bolt holes. Use anchor bolts of accepted standards
and sufficient to ensure seave fitting in the foun-
dation.
Provide sufficient space in the foundation to
accommodate the anchor bolts. If necessary, pro-
vide concrete risers.
Usually the pump and its drive are mounted on a
common base plate.
4.2.1 Setting the base plate for anchoring
• Clean the foundation surface thoroughly.
• Put shims on the foundation surface (approx 20-
25 mm thick), one on each side of the bolt hole (as
an alternative, leveling screws can be used). .
• Lay the base plate and level in both directions with
extra shims. The base plate should be level to
within 0.5 mm per 1 m.
If anchor bolts have been pre-cast in the founda-
tion slightly tighten the anchor bolts. Otherwise
let them hang in the foundation holes.
4.3 Initial alignment
There are many methods of installing
pump units to their foundations. The
correct method depends on the size of
the pump unit, its location and noise vib-
ration limitations. Non-compliance with
the provision of correct foundation and
installation may lead to failure of the
pump and, as such, would be outside the
terms of the warranty.
Type of
base
Article
number
Length
mm  mm
Length
thread mm
4 740707 300 20 60
5 740708
6 740709
7 740710 300 24 100
8 740711
9 740712
10 4084125
CAUTION!
Before connecting the couplings verify
the motor rotation direction.
CAUTION!

English
12 Wilo AG 09/2005
4.3.1 Thermal expansion
4.3.2 Alignment methods
Ensure pump and driver are isolated electrically
and the half couplings are disconnected. Ensure
that the pump pipework, suction and discharge,
is disconnected.
Although the pump will have been aligned at the
factory it is most likely that this alignment will
have been disturbed during transportation or
handling. If necessary, align the motor to the
pump, not the pump to the motor.
Alignment
Parallelism and concentricity check:
Admissible margin for a motor with roller bearings:
= 0.15 mm parallel checking
= 0.1 mm angular checking
If necessary, improve the machine alignment:
Complete unit mounted on common base plate:
The machines are first aligned accurately in our
workshops. Usually, any misalignment observed
on-site is due to a wrong adjustment under the
base plate (disturbed during transport or because
of forces exerted by the pipework). It is only
necessary to rectify the adjustment under base
plate. If it proves to be insufficient, modify the
motor and the pipeworks adjustment.
Never connect the electric motor before the
setting has been completely finished.
The pump and motor will normally have
to be aligned at ambient temperature
and should be corrected to allow for
thermal expansion at operating tempe-
rature. In pump installations involving
high liquid temperatures, the unit should
be run at the actual operating tempera-
ture, shut down and the alignment che-
cked immediately.
The alignment MUST be checked.
Check the alignment at three or four
points, before pipeworks assembly.
The alignment will be definitive only
after pipework connection (see § 4.4.4.).
CAUTION!
CAUTION!
CAUTION!
with a rule with a comparator
with a sliding rule with a caliper gauge
CAUTION!

English
Installation and maintenance instructions Wilo-Horizontal pumps NPG
4.4 Piping
4.4.1 Suction and discharge pipework
The dimensions of the pipes do not directly
depend on suction and discharge diameters of the
pump.
a) First, choose a flow speed < 2 m/s at suction,
and about 3 m/s at discharge.
b) Take into account the available NPSH, which
must be superior to the required NPSH of the
pump.
Never use pump as a support for piping. Do not
mount expansion joints in such a way that their
force, due to internal pressure, may act on the
pump flange.
Maximum forces and moments allowed on the
pump flanges vary with the pump size and type.
These external strains may cause misalignment,
hot bearings, worn couplings, vibrations and the
possible failure of the pump casing.
When designing the pipes (§ 4.4.2.1, § 4.4.2.2,
§ 4.4.3.1) take necessary precautions in order not
to exceed maximum allowed strains.
Forces and moments applied to the pump flanges
must never exceed the values shown in the table
below:
Forces and moments values are applied to the
whole flanges and not flange-by-flange. For their
sharing out on the pump flanges, refer to standard
NFCR 13 931.
4.4.2 Suction piping
4.4.2.1 Design of a flooded suction line
The suction line must be as short and direct as
possible, never mount an elbow directly on the
Protective covers are fitted to the pipe
connections to prevent foreign bodies
entering during transportation and
installation. Ensure that these covers are
removed from the pump before connec-
ting any pipes.
CAUTION!
DN
Flange
Forces (daN) Moments (m.daN)
Fy Fz Fx ¦FMy Mz Mx ¦M
Vertical Discharge 150 160 200 180 310 45 60 80 110
200 215 265 240 415 85 100 125 180
250 270 335 300 520 125 145 180 260
300 320 400 360 625 170 200 240 355
350 375 465 420 730 220 255 310 455
400 430 530 480 835 275 320 390 570
450 485 600 540 940 340 390 480 705
500 540 665 600 1040 410 470 580 850
Horizontal Suction 150 180 160 200 315 45 60 80 110
200 240 215 265 415 85 100 125 180
250 300 270 335 520 125 145 180 260
300 360 320 400 625 170 200 240 355
350 420 375 465 730 220 255 310 455
400 480 430 530 835 275 320 390 570
450 540 485 600 940 340 390 480 705
500 600 540 665 1040 410 470 580 850
Ensure piping and fittings are flushed
before use.
CAUTION!
Ensure piping for hazardous liquids is
arranged to allow pump flushing before
removal of the pump.
CAUTION!

English
14 Wilo AG 09/2005
inlet flange of the pump.
a) Avoid sharp elbows or sudden narrowing. Use
convergent d20° (total angle).
b) Arrange the pipework so that there are no air
pockets (no bulges).
c) If high points cannot be avoided in suction line,
provide them with air relief cocks.
d) If a strainer is necessary, its net area should be
three or four times the area of the suction pipe.
e) If an inlet valve is necessary, choose a model
with direct crossing.
4.4.2.2 Design of a suction lift line
The inlet pipe must be as short and as direct as
possible, never place an elbow directly on the
pump inlet nozzle.
a) Avoid sharp elbows or sudden narrowings. Use
convergents 20° (total angle) with upright gene-
rating.
b) Arrange that the suction pipework is inclined
upwards towards the pump ensuring that there
are no peaks.
c) If a foot valve is necessary, do not oversize it
because it would generate pulsations (valve bea-
ting).
4.4.3 Discharge piping
4.4.3.1 Design of a discharge line
a) If discharge line is provided with a divergent, its
total angle will be between 7° and 12°.
b) Install the discharge valve after the non-return
valve downstream.
The non-return valve will be set in the discharge
pipe to protect the pump from any excessive
pressure surge and from reverse rotation.
If necessary, a control manometer can be connec-
ted on the pipework.
4.4.4 Final checks
a) Check the tightening of anchor bolts. Tighten
them if necessary.
b) Check that protective covers on suction and
discharge flanges are removed.
c) Check that holes of pipework flanges are paral-
lel and correspond to those of the pump.
d) Tighten suction and discharge flanges.
4.5 Electrical connections
Electrical connections must be made by a quali-
fied Electrician in accordance with relevant local
national and international regulations. This
includes any grounding.
It is important to be aware of the EUROPEAN
DIRECTIVE on electromagnetic compatibility
when wiring up and installing equipment on site.
Attention must be paid to ensure that the tech-
niques used during wiring/installation do not
increase electromagnetic emissions or decrease
the electromagnetic immunity of the equip-
ment, wiring or any connected devices.
The motor must be wired up in accordance with
the motor manufacturer's instructions (nor-
mally supplied within the terminal box) inclu-
ding any temperature, earth leakage, current
and other protective devices as appropriate. The
Flooded suction configuration
Do not tighten flanges before the final
check (see § 4.4.4).
CAUTION!
Do not tighten flanges before the final
check (see § 4.4.4).
Installation of the control manometer
Do not tighten flanges before the final
check (see § 4.4.4.).
CAUTION!
CAUTION!

English
Installation and maintenance instructions Wilo-Horizontal pumps NPG
identification nameplate should be checked to
ensure the power supply is appropriate.
A device to provide emergency stopping shall be
fitted.
Carry out the ground connections according to the
current local regulations.
4.6 Final shaft alignment check
a) Check the alignment pump-motor according to
the procedure § 4.3.2. Rectify if necessary by
adjusting the motor only.
b) Check by hand that the pump turns freely.
A binding indicates a distortion of the pump,
which is due to excessive pipes strains. If neces-
sary the pipework design must be re-examined.
c) If it provided, connect auxiliary pipe systems
(hydraulic, pneumatic, sealing system).
d) Control tightness and functionality of auxiliary
piping.
4.7 Protection systems
If there is any possibility of the system allowing
the pump to run against a closed valve or below
minimum continuous safe flow a protection
device should be installed to ensure the tempera-
ture of the liquid does not rise to an unsafe level.
If there are any circumstances in which the system
can allow the pump to run dry, or start up empty, a
power monitor should be fitted to stop the pump
or prevent it from being started. This is particularly
relevant if the pump is handling a flammable
liquid.
If leakage of product from the pump or its associa-
ted sealing system can cause a hazard it is recom-
mended that an appropriate leakage detection
system is installed.
To prevent excessive surface temperatures at
bearings it is recommended that temperature or
vibration monitoring are carried out. See sections
5.5.4 and 5.5.5.
If a defect of cooling can lead to temperature hig-
her than those acceptable a system of cooling
surveillance must be installed.
Except when explicitly required by the customer in
the specifications, when a possibility of reverse
rotation exists the customer must install a reverse
rotation protection device.
The customer must install all equipment required
to avoid water hammer.
5 Commisioning, start-up, operation and
shutdown
These operations must be carried out by fully
qualified personnel.
5.1 Direction of rotation
5.2 Guarding
Guarding is supplied fitted to the pump set.
If this has been removed or disturbed ensure
that all the protective guards around the pump
coupling and exposed parts of the shaft are
securely fixed.
5.3 Priming and auxiliary supplies
These operations must be carried out by person-
nel with approved qualifications.
To avoid any risk of jamming, the direc-
tion of rotation will be checked after pri-
ming of the pump (§ 5.3.1, § 5.3.2) and
before the first start (§ 5.4.2).
CAUTION!
Starting or operating pumps with the
wrong direction of rotation can be harm-
ful to the pumps. Ensure that the pump
rotation is the same as the arrow on the
pump casing.
It is preferable to check the direction of
rotation before installing the coupling. If
not, the pump must be filled in with the
liquid before start-up.
If maintenance work has been carried
out to the site's electricity supply, the
direction of rotation should be re-che-
cked as above in case the supply phasing
has been altered.
Ensure all electrical, hydraulic, pneu-
matic, sealant and lubrication systems
(as applicable) are connected and opera-
tional.
Ensure the inlet pipe and pump casing
are completely full of liquid before star-
ting continuous duty operation.
CAUTION!
CAUTION!
CAUTION!
CAUTION!

English
16 Wilo AG 09/2005
5.3.1 Priming of a flooded pump
Close the discharge valve; fill the pump by ope-
ning the suction valve. Let air escape by removing
the plug located on the pipework.
The discharge pipe is headed and there is a by-
pass valve on the check valve, open slightly the
discharge valve and the by-pass of the check
valve.
When the pump is totally free of air bubbles,
replace the plugs.
5.3.2 Priming of a sump suction pump
* With foot valve:
Fill suction pipe and casing with liquid from an
independent source (pressure 1 to 2 bars).
Let air escape by removing the plugs located on
the pipework.
When the pump is totally free of air bubbles,
replace the plugs.
* Without foot valve:
Priming may be accomplished by means of venting
system.
5.4 Starting the pump
5.4.1 Bring controls and preparation before the first
starting and after each service call
Necessarily:
• Check the tightening of the different plugs.
• Check that the gland lightly tightens the packing
rings.
Install all protection systems and more particu-
larly the coupling guard and the shield grid
(reference [7450]) of the bearing.
• Open all suction valves (if existing).
• Close the outlet valve and the bypass valve.
• Ensure inlet pipe and pump casing are completely
full of liquid.
5.4.2 First pump start-up
• Start motor and check outlet pressure.
• If pressure is satisfactory, slowly OPEN outlet
valve.
• Do not run the pump with the outlet valve closed
for a period longer than 30 seconds.
• If NO pressure, or LOW pressure, STOP the pump.
Refer to faultfinding chart for fault diagnosis.
• The pump should run smoothly and without vibra-
tion.
• The pump must never run at a capacity of less than
40 % of that at the best efficiency.
Never remove a plug when the pump is running.
5.5 Running the pump
5.5.1 Venting the pump
Vent the pump to enable all trapped air to
escape taking due care with hot or hazardous
liquids.
Under normal operating conditions, after the
pump has been fully primed and vented, it
should be unnecessary to re-vent the pump.
5.5.2 Pump fitted with a stuffing box
If the pump has a packed gland there must be
some leakage from the gland. Gland nuts should
initially be finger tight only. Leakage should take
place soon after the stuffing box is pressurized. If
no leakage takes place the packing will begin to
overheat. If overheating takes place the pump
should be stopped and allowed to cool before
being restarted.
When the pump is restarted it should be checked
to ensure leakage is taking place at the packed
gland.
Priming of a flooded suction pump
Priming of a suction pump configuration
with foot valve
Foot valves are not recommended when
the pumped liquid has suspended solid
particles. They may lodge between foot
valve seat and shutter.
NOTE:
Risk of seal ring overheating.
Check the direction of rotation of the
motor. Refer to the rotation arrow of the
pump.
Suction valves must be fully open when
pump is running. Never run the pump
dry, it will cause damage.
CAUTION!
CAUTION!

English
Installation and maintenance instructions Wilo-Horizontal pumps NPG
When adjusting an operating stuffing box (shield
grids removed for this operation) the operator
must be very careful. Safety gloves are compul-
sory and loose clothes are not allowed (above all
to the arms) to avoid being caught by the pump
shaft.
The pump should be run for ten minutes with
steady leakage and the gland nuts tightened by
10 degrees at a time until leakage is reduced to an
acceptable level.
The temperature of the gland should be checked
after each round of tightening. If the temperature
starts to climb rapidly then back off the gland nuts
until the temperature drops down. Wait for the
temperature to stabilize before tightening again.
The leakage must not be reduced below a rate of
20 drops per minute.
Bedding in of the packing may take several hours.
Shield grids being removed during installation of
the gland packing, it must be ensured that they
are replaced as soon as this operation is comple-
ted.
5.5.3 Pump fitted with mechanical seal
A mechanical seal ensures a seal without leakage
and does not need any adjustment. Nevertheless
if a light leakage occurs during start-up, it should
disappear after the initial running in of the friction
faces.
Safety instructions when the pump is running.
If hot or freezing components of the machine can
present a danger to operators, they must be shiel-
ded to avoid accidental contact. If a 100 % pro-
tection is not possible, the machine access must
be confined to the maintenance staff only.
If the temperature is greater than 80 °C, a war-
ning plate must be clearly placed on the pump.
It is strictly forbidden to open switch cupboards,
switch boxes, or all other live electric equipment.
If it is necessary to open them in order to take rea-
dings, to carry out tests or adjustments for
example, only a skilled technician may do them
with adapted tools. Make sure that physical pro-
tections against electrical risks are used.
5.5.4 Bearings
It is important, particularly with grease lubrication,
to keep a check on bearing temperatures. After
start up the temperature rise should be gradual,
reaching a maximum after approximately 1.5 to
2 hours. This temperature rise should then remain
constant or marginally reduce with time.
5.5.5 Normal vibration levels, alarm and trip
For guidance, pumps generally fall under a classi-
fication for rigid support machines within the
International rotating machinery standards and
the recommended maximum levels below are
based on those standards.
Mechanical Seal
For NPG150-200,
200-250, 200-315
200-355, 250-250
250-315, 300-300,
65-315A, 100-315A
Simple mechanical seal
Other NPG
Balanced mechanical seal
Other NPG
Never run a mechanical seal dry, even for
a short while.
Vibration velocity - unfiltered mm/s (in./s)r.m.s.
Normal Nd5.6 (0.22)
Alarm Nx1.25 d7.1 (0.28)
Shutdown trip Nx2.0 d11.2 (0.44)
CAUTION!

English
18 Wilo AG 09/2005
The example (N) value is given for the preferred
operating flow region (typically this may extend to
70 to 120 % of the pump best efficiency point);
outside the preferred flow region the actual vibra-
tion experienced may be multiplied by up to 2.
These standard values can vary with the rotational
speed and the power absorbed by the pump. For
any special case, do not hesitate to consult us.
5.5.6 Stop/start frequency
Pump sets are normally suitable for the number of
equally spaced stop/starts per hour shown in the
table below. Check actual capability of the driver
and control/starting system before commissio-
ning.
Where duty and standby pumps are installed it is
recommended that they are run alternately every
week.
5.6 Stopping and shutdown
5.6.1 Stopping and restarting in continuous running
According to hydraulic conditions of the installa-
tion and its automation degree, stop and restart
procedures can have different forms. Neverthe-
less all of them must respect imperatively the fol-
lowing rules:
Stopping:
a) Avoid that the unit turns in the opposite direc-
tion to the normal running.
b) Make sure that the discharge line pressure does
not reach the foot valve.
c) Avoid a continuous running below the authori-
zed flow rate (see § 5.4.2).
Restart:
a) Ensure that the pump is completely full of liquid.
b) Ensure a continuous supply with a sufficient
available NPSH.
c) Ensure a backpressure so that the motor power
is not in excess.
Protect the pump against water hammer when
stopping or starting
Shutdown:
5.7 Hydraulic, mechanical and electrical duty
This product has been supplied to meet the per-
formance specifications of your purchase order,
however it is understood that during the life of the
product these may change. The following notes
may help the user decide how to evaluate the
implications of any change.
5.7.1 Specific gravity (SG)
Pump capacity and total head in meters (feet) do
not change with SG, however pressure displayed
on a pressure gauge is directly proportional to SG.
Power absorbed is also directly proportional to SG.
It is therefore important to check that any change
in SG will not overload the pump driver or over-
pressurize the pump.
5.7.2 Viscosity
For a given flow rate the total head reduces with
increased viscosity and increases with reduced
viscosity. Also for a given flow rate the power
absorbed increases with increased viscosity, and
reduces with reduced viscosity.
5.7.3 Pump speed
Changing pump speed effects flow, total head,
power absorbed, NPSHR, noise and vibration. Flow
varies in direct proportion to pump speed, head
varies as speed ratio squared and power varies as
speed ratio cubed.
The new duty, however, will also be dependent on
the system curve. If increasing the speed, it is
important therefore to ensure the maximum
pump working pressure is not exceeded, the driver
is not overloaded, NPSHA > NPSHR, and that noise
and vibration are within local requirements and
regulations.
5.7.4 Pumped flow
Flow must not fall outside the minimum and maxi-
mum continuous safe flow shown on the pump
performance curve and or data sheet.
5.8 Pumps for Food Use or Potable Water (ACS
range)
If the pump has not been specifically ordered for a
food or drinking water application it must not be
used for these types of applications. If it has been
ordered for this type of application the following
Alarm and trip values for installed pumps
should be based on the actual measure-
ments (N) taken on site on the bearing
housings of the pump in the fully com-
missioned as new condition. Measuring
vibration at regular intervals will then
show any deterioration in pump or sys-
tem operating conditions.
Motor rating kW (hp) Maximum stop/starts
per hour
Up to 15 (20) 15
Between 15 (20) and 90 (120) 10
90 (120) to 150 (200) 6
Above 150 (200) Refer
Respect the starting frequency imposed
by the motor manufacturer.
CAUTION!
CAUTION!
Close the outlet valve and stop the
motor. Eventually close the inlet valve.
For prolonged shutdowns and especially
when ambient temperatures are likely to
drop below freezing point, the pump and
any cooling and flushing arrangements
must be drained or otherwise protected.
CAUTION!
CAUTION!

English
Installation and maintenance instructions Wilo-Horizontal pumps NPG
recommendations are to be followed.
5.8.1 Cleaning prior to operation
Pumps that are to be used for a food or drinking
water application should be cleaned before being
put into initial operation and after the installation
of spare parts that are in contact with the liquid.
Cleaning once the pump has been commissioned
will depend on the application and operating con-
ditions. The user must ensure that the cleaning
procedures are suitable for the application and
operating conditions, and local regulations.
6Maintenance
6.1 General
It is the plant operator's responsibility to ensure
that all maintenance, inspection and assembly
work is carried out by authorized and qualified
personnel who have adequately familiarized
themselves with the subject matter by studying
this manual in detail (see also section 1.6.2.).
Any work on the machine must be performed
when it is at a standstill. It is imperative that the
procedure for shutting down the machine is follo-
wed, as described in section 5.6.
On completion of work all guards and safety
devices must be re-installed and made operative
again.
Before restarting the machine, the relevant
instructions listed in section 5, Commissioning,
start up, operation and shut down must be obser-
ved.
Oil and grease leaks may make the ground slip-
pery. Machine maintenance must always begin
and finish by cleaning the ground and the exte-
rior of the machine.
Before working on the pump, take measures to
prevent an uncontrolled start. Puta warning board
on the starting device with the words:
"Machine under repair: do not start".
With electric drive equipment, lock the main
switch open and withdraw any fuses. Put a war-
ning board on the fuse box or main switch with the
words:
"Machine under repair: do not connect".
Never clean equipment with inflammable solvents
or carbon tetrachloride. Protect yourself against
toxic fumes when using cleaning agents.
6.2 Maintenance schedule
6.2.1 Standard maintenance
Roller bearing
6.2.1.1 For NPG150-200, 200-315, 200-355, 250-250,
250-315, 300-300, 65-315A, 100-315A
The bearing housings are provided with sealed for
life ball bearings. No maintenance is required.
6.2.1.2 For other NPG
The bearings fitted are prepacked with grease at
the factory. When the regressing period is reached
it is necessary to remove as much of the old grease
as possible with a clean lint free cloth and repack
the bearings with fresh grease.
The grease used in factory for first filling is:
SHELL ALVANIA R2
Its equivalents:
• MOBIL: Mobilux EP 2,
• TOTAL: Multis 2,
• ELF: ELF MULTI
Lubrication in hours frequency* of operation Added quantity in cm3
Pump type Coupling side Pump side Coupling side Pump side
NPG150 - 500 4 000 4 000 30 30
NPG200 - 250 6 000 6 000 15 15
NPG200 - 400 8 000 8 000 25 25
NPG200 - 500 4 000 4 000 30 30
NPG250 - 355 8 000 8 000 25 25
NPG250 - 400 8 000 8 000 25 25
NPG250 - 500 4 000 4 000 30 30
NPG300 - 400 8 000 8 000 25 25
NPG300 - 450 4 000 4 000 30 30
NPG300 - 500 3 500 3 500 50 50
NPG350 - 350 4 000 4 000 40 40
NPG400 - 500 3 500 3 500 50 50
NPG400 - 650 3 500 3 500 50 50
NPG500 - 500 3 500 3 500 50 50
*At least once a year

English
20 Wilo AG 09/2005
6.2.2 Routine inspection (daily/weekly)
a) Check operating behavior. Ensure noise, vibra-
tion and bearing temperatures are normal.
b) Check that there are no abnormal fluid or lubri-
cant leaks (static and dynamic seals) and that any
sealant systems (if fitted) are full and operating
normally.
c) Pump fitted with a stuffing box: leakage of 20
drops per minute.
d) Pump fitted with a mechanical seal: no leakage.
e) Check the level and condition of oil lubricant.
On grease lubricated pumps, check running hours
since last recharge of grease or complete grease
change.
6.2.3 Periodic inspection (six monthly)
b) Check pump-running records for hourly usage
to determine if bearing lubricant requires chan-
ging.
c) The coupling should be checked for correct
alignment and worn driving elements.
Ensure that your equipment corresponds to the
arrangements of this leaflet.
6.2.4 Mechanical seals
The current maintenance is limited to seal control.
It is necessary to detect any small leakage which
announces the beginning of the deterioration of
friction faces or secondary seal elements (rings,
bellows, synthetic membranes). It is advisable to
stop the pump as soon as possible. Have an appro-
ved seal vendor replace or repair the seal.
6.2.5 Gland packing
6.2.5.1 Pump fitted with a packed gland
A well run in and correctly adjusted packing gland
requires little maintenance.
If, after some time, the leakage becomes too
great, the gland should be tightened again in order
to return these to a normal level.
If re-tightening is not possible, new packing must
be installed.
6.2.5.2 Gland packing inspection and removal
a) Remove the shield guards
b) Slide back the gland
c) Remove the packing rings with an extractor
designed for this purpose (including the lantern
ring if it exists; note its position and its direction of
rotation).
d) Inspect the state of the sleeve surface; the pre-
sence of many marked grooves will indicate that it
must be replaced.
e) Carefully clean the different pieces of the
packing gland.
6.2.5.3 Gland packing fitting
If the packing is supplied as cord the packing must
be cut so that the external diameter is lightly tigh-
tened and there is an initial gap between the
sleeve and the packing ring.
For that purpose, wind the packing helically
around the shaft sleeve or a chuck of the same
diameter. (Take precautions to avoid damaging
sleeve)
Setting of packing
Follow the instructions:
a) Assemble of the packing in S.
b) Stagger by about 90° between two rings.
c) Assemble packing after packing.
The following checks should be made
and the appropriate action taken to
remedy any deviations:
a) Check foundation bolts for security of
attachment and corrosion.
If a check shows a bad running of the
motor pump unit, the user must:
Refer to the "fault finding chart" chapter 7
of this leaflet to apply the recommended
solutions.
CAUTION!
CAUTION!
NOTE:
Ensure a tightening on the stuffing box
housing and not on the sleeve.
CAUTION!

English
Installation and maintenance instructions Wilo-Horizontal pumps NPG
After setting the last packing ring, secure the
packing with the gland and tighten the nut by
hand.
After tightening, the shaft should turn by hand as
easily as before the setting of the packing.
6.3 Spare parts
6.3.1 Ordering of spares
When ordering spares the following information
should be quoted:
1 Pump serial number.
2 Pump size.
3 Part name
4 Part number
5 Number of parts required.
The pump size and serial numberare shown on the
pump nameplate.
To ensure continued satisfactory operation,
replacement parts to the original design specifica-
tion should be of our supply. Any change to the
original design specification (modification or use
of a non-standard part) will invalidate the pump’s
safety certification.
6.3.2 Storage of spares
Spares should be stored in a clean dry area away
from vibration. Inspection and re-treatment of
metallic surfaces (if necessary) with preservative
is recommended at 6 monthly intervals.
6.4 Recommended spares and consumable items
[1500], [2250], [3011], [3012], [4130], [4610]
Dimensions in millimeters Gland packing
Pump Stuffing box size D1 D2 D3 D4 D5 L1 Qty ■
mm
NPG150-200 44/64 38 44 64 86 M12 45 4 10
NPG150-500 55/90 55 65 90 120 M16 65 5 12
NPG200-250 44/64 38 44 64 86 M12 45 4 10
NPG200-315 56/76 50 56 76 86 M12 45 4 10
NPG200-355 56/76 50 56 76 86 M12 45 4 10
NPG200-400 49/85 49 60 85 110 M14 65 5 12
NPG200-500 55/90 55 65 90 120 M16 65 5 12
NPG250-250 56/76 50 56 76 86 M12 45 4 10
NPG250-315 56/76 50 56 76 86 M12 45 4 10
NPG250-355 49/85 49 60 85 110 M14 65 5 12
NPG250-400 55/90 55 65 90 120 M16 65 5 12
NPG250-500 55/90 55 65 90 120 M16 65 5 12
NPG300-300 56/76 40 56 76 86 M12 45 4 10
NPG300-400 55/90 55 65 90 120 M16 65 5 12
NPG300-450 55/90 55 65 90 120 M16 65 5 12
NPG300-500 74/120 74 90 120 150 M16 64 4 14
NPG350-350 55/90 55 65 90 120 M16 65 5 12
NPG400-500 74/120 74 90 120 150 M16 64 4 14
NPG400-650 74/120 74 90 120 150 M16 64 4 14
NPG500-500 80/132 80 100 132 180 M16 72 4 16

English
22 Wilo AG 09/2005
Destroy all the gaskets after dismantling, replace
them when reassembling.
It is recommended that bearings are not reused
after any removal from the shaft.
After serving during two years, replace the gland
packing.
6.5 Disassembly
Refer to section 1.6, Safety, and section 6 Main-
tenance, before dismantling the pump.
Repair of the pump
If the pump presents abnormalities or a persis-
tent malfunction, contact immediately the
After-sales Service.
According to the After-sales Service instructions,
disassembly will be limited to the dismantling of
the pump.
Disconnect the unit from power
• Close the inlet valve (if fitted) and outlet valve.
• Wait for the moment when the pump casing is
cooled and at ambient temperature.
Drain pump
Dismantle inlet and outlet pipeworks as well as
all pipeworks.
REMOVE PUMP TAKING INTO ACCOUNT SAFETY
(§ 1) AND HANDLING (§ 2.2) PROCEDURES.
ANY DISASSEMBLY, REPAIR OR REASSEMBLY
WILL BE CARRIED OUT UNDER FLOWSERVE'
RESPONSABILITY, EITHER DIRECTLY BY THE
AFTER-SALES SERVICE OR BY OTHER FLOW-
SERVE-AGENTS WHO WILL GET THE REQUIRED
INSTRUCTIONS AND APPROVALS. THIS IS THE
CASE OF AUTHORIZED REPAIRERS WHOSE
ADDRESSES AND TELEPHONE NUMBERS WILL BE
GIVEN ON REQUEST.
7 Faults, Causes and Remedies
Before dismantling the pump for over-
haul, ensure genuine replacement parts
are available. Refer to sectional dra-
wings for part numbers and identifica-
tion.
CAUTION!
Trouble Possible Causes Solutions
Insuffcient flowrate Pump or suction pipe not completely
filled
Check and complete filling
Air bubbles in pipes Check and desecrate the pipes
Suction level too low • Check: the available NPSH > the
required NPSH
• Reduce geometrical suction lift
• Reduce head losses in pipes and in fit-
tings (diameter increase and appropri-
ate fitting positions)
• Check valves and strainers
• Check the immersion head of the suc-
tion valve
Wrong rotation Reverse 2 phases on motor terminal
boxes
The motor is running on 2 phases only Check and control the motor electrical
power supply
Motor running too low Check the connection in the terminal
box according to the voltage
Total manometric head system higher
than pump differential head
• Check the discharge head
• Check the head losses in discharge
pipes (partly closed valve, foreign par-
ticles, back pressure too high)
• Modify the installation or change the
pump set
Pipes (valves, filter...) Control, dismantle and clean
Worn wear-ring surfaces Foresee pump mending
Irregular pump running Pump or suction pipe not completely
filled
Check and complete filling
Air bubbles in pipes Check and desecrate the pipes
The motor is running on 2 phases only Check and control the motor electrical
power supply
Seizure, jamming CONSULT US
Excessive strains on flanges Check the flange connections and elimi-
nate strains (pipe positioning or elastic
sleeves mounting)
Defective motor bearings CONSULT US

English
Installation and maintenance instructions Wilo-Horizontal pumps NPG
Driver overload The motor is running on 2 phases only Check and control the motor electrical
power supply
Total manometric head system lower
than pump differential head
Throttle at discharge valve or trim the
impeller (contact our local agent)
Seizure, jamming CONSULT US
Excessive strains on flanges Check the flange connections and elimi-
nate strains (pipe positioning or elastic
sleeves mounting)
Defective motor bearings CONSULT US
Specific gravity or viscosity of liquid too
high
Consult our local agent to analyze the
problem
Mechanical seal leak Seizure, jamming CONSULT US
Excessive strains on flanges Check the flange connections and elimi-
nate strains (pipe positioning or elastic
sleeves mounting)
Defective gland packing on the shaft • Check and replace all the gland
packing parts
• Mechanical seal
Defective motor bearings CONSULT US
Equipment vibration Pump or suction pipe not completely
filled
Check and complete filling
Air bubbles in pipes Check and desecrate the pipes
Suction level too low • Check: the available NPSH > the
required NPSH
• Reduce geometrical suction lift
• Reduce head losses in pipes and in fit-
tings (diameter increase and appropri-
ate fitting positions)
• Check valves and strainers
• Check the immersion head of the suc-
tion valve
Total manometric head system higher
than pump differential head
• Check the discharge head
• Check the head losses in discharge
pipes (partly closed valve, foreign par-
ticles, back pressure too high)
• Modify the installation or change the
pump set
Total manometric head system lower
than pump differential head
Throttle at discharge valve or trim the
impeller (contact our local agent)
Pipes (valves, filter...) Control, dismantle and clean
Insufficient flow rate Check the suction and discharge pipes
(valves, back pressure)
Seizure, jamming CONSULT US
Excessive strains on flanges Check the flange connections and elimi-
nate strains (pipe positioning or elastic
sleeves mounting)
Defective motor bearings CONSULT US
Misalignment Check the alignment of the pump and of
its driver
Foundations not sufficiently rigid Check the setting of base plates: tighte-
ning, bad adjustment, seal
Trouble Possible Causes Solutions