Grundfos SR User manual

SR, SF
GRUNDFOS INSTRUCTIONS
Installation and operating instructions

2
LIMITED WARRANTY
Products manufactured by GRUNDFOS PUMPS CORPORATION (Grundfos) are warranted to the original
user only to be free of defects in material and workmanship for a period of 24 months from date of installation,
but not more than 30 months from date of manufacture. Grundfos’ liability under this warranty shall be limited
to repairing or replacing at Grundfos’ option, without charge, F.O.B. Grundfos’ factory or authorized service
station, any product of Grundfos’ manufacture. Grundfos will not be liable for any costs of removal, installa-
tion, transportation, or any other charges which may arise in connection with a warranty claim. Products which
are sold but not manufactured by Grundfos are subject to the warranty provided by the manufacturer of said
products and not by Grundfos’ warranty. Grundfos will not be liable for damage or wear to products caused by
abnormal operating conditions, accident, abuse, misuse, unauthorized alteration or repair, or if the product
was not installed in accordance with Grundfos’ printed installation and operating instructions.
To obtain service under this warranty, the defective product must be returned to the distributor or dealer of
Grundfos’ products from which it was purchased together with proof or purchase and installation date, failure
date, and supporting installation data. Unless otherwise provided, the distributor or dealer will contact
Grundfos or an authorized service station for instructions. Any defective product to be returned to Grundfos or
a service station must be sent freight prepaid; documentation supporting the warranty claim and/or a Return
Material Authorization must be included if so instructed.
GRUNDFOS WILL NOT BE LIABLE FOR ANY INCIDENTAL OR CONSEQUENTIAL DAMAGES, LOSSES,
OR EXPENSES ARISING FROM INSTALLATION, USE, OR ANY OTHER CAUSES. THERE ARE NO
EXPRESS OR IMPLIED WARRANTIES, INCLUDING MERCHANTABILITY OR FITNESS FOR A PARTICU-
LAR PURPOSE, WHICH EXTEND BEYOND THOSE WARRANTIES DESCRIBED OR REFERRED TO
ABOVE.
Some jurisdictions do not allow the exclusion or limitation of incidental or consequential damages and some
jurisdictions do not allow limit actions on how long implied warranties may last. Therefore, the above limita-
tions or exclusions may not apply to you. This warranty gives you specific legal rights and you may also have
other rights which vary from jurisdiction to jurisdiction.

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CONTENTS
Page
1. Preinstallation 3
2. System overview 3
3. Applications 3
4. Identification 4
5. Operating conditions 4
5.1 Maximum ambient temperature 4
5.2 Fluid temperature 4
5.3 Humidity 4
5.4 Minimum inlet pressure 4
5.5 Maximum inlet pressure 4
5.6 Maximum operating pressure 4
5.7 Pump cycling 4
6. Installation 4
6.1 Handling 4
6.2 Pump location 4
6.3 Connection 4
6.4 Foundation 5
6.5 Pipework in general 5
6.6 Suction piping 5
6.7 Discharge piping 5
6.8 Bypass 6
7. Electrical connection 6
7.1 Motor 6
7.2 Supply power 6
7.3 Field wiring 6
7.4 Motor protection 6
7.5 Pump start-up 6
7.5.1 Priming 6
7.6 Check motor rotation 6
7.6.1 Starting and adjusting 7
8. Operation and maintenance 7
8.1 Operation 7
8.2 Maintenance 7
8.3 Taking pump out of operation 7
9. Service 7
10. Troubleshooting 8
10.1 Preliminary tests 8
10.2 Troubleshooting chart 9
11. Disposal 11
Shock hazard
A faulty motor or wiring can cause electrical shock that could be
fatal, whether touched directly or conducted through standing
water. For this reason, proper grounding of the pump to the
grounding terminal of the power supply is required for safe instal-
lation and operation.
In all installations, the above-ground metal plumbing should be
connected to the power supply ground as described in Article
250-80 of the NEC.
1. Preinstallation
Check the condition of the pump
Examine your pump carefully to make sure that no damage has
occurred during shipment.
Your Grundfos SR, SF pump should remain in its shipping carton
until it is ready to be installed. This carton has been specially
designed to protect the pump from damage. During unpacking
and prior to installation, care should be taken to ensure the pump
is not dropped or mishandled. Immediately report any damage in
writing to the transportation company and ask to have it
inspected. Do not destroy packing materials until the shipment is
inspected and the claim is settled.
2. System overview
Fig. 1 Component overview of an SR, SF pump
1) Must not be used for lifting the entire pump.
3. Applications
The Grundfos SR, SF end-suction pumps are service pumps
designed to pump fluids in a wide range of applications.
Acceptable fluids include:
• Hot and cold water
• Thin, clean, non-aggressive and non-explosive liquids.
Consult manufacturer for fluids containing chlorine or hydrocar-
bons.
When pumping liquids with a density and/or viscosity higher than
that of water, motors with correspondingly higher outputs must be
used, if required.
The O-rings and the mechanical shaft seal chosen must be suit-
able for the liquid to be pumped.
For further information, contact Grundfos.
SAFETY WARNING
Electrical work
All electrical work should be performed by a qualified
electrician in accordance with the latest edition of the
US National Electrical Code (NEC), local codes and
regulations.
Prior to installation, read these installation and oper-
ating instructions. Installation and operation must
comply with local regulations and accepted codes of
good practice.
Keep these instructions with the pump for future ref-
erence.
TM03 1890 3305
Pos. Description Pos. Description
1 Suction port 6 Motor feet
2 Discharge port 7 Drain/venting plugs
3 Motor lifting eye 1) 8 Fan cover
4 Terminal box 9 Pump head
5 Pump housing

4
4. Identification
Fig. 2 Example of SR, SF nameplate
5. Operating conditions
5.1 Maximum ambient temperature
104°F (40°C)
Consult Grundfos for higher ambient temperature conditions.
5.2 Fluid temperature
–13°F to +212°F (–25°C to +100°C)
• 176°F continuous (80°C)
• 212°F intermittent (100°C).
5.3 Humidity
Max. 95%.
5.4 Minimum inlet pressure
According to the NPSHR curve + a safety margin of minimum 2
feet of head.
5.5 Maximum inlet pressure
The actual inlet pressure and the pressure when the pump is run-
ning against a closed valve must always be lower than the maxi-
mum permissible operating pressure.
5.6 Maximum operating pressure
174 psi (12 bar) at 212°F (100°C).
5.7 Pump cycling
• 1 hp to 5 hp: Max. 20 starts per hour
• 7.5 hp to 15 hp: Max. 15 starts per hour
• 20 hp to 40 hp: Max. 10 starts per hour.
6. Installation
6.1 Handling
Fig. 3 Pumps should be lifted by means of nylon straps and
shackles, if required.
6.2 Pump location
The pump should be located:
• in a dry, well-ventilated area which is not subject to freezing or
extreme variations in temperature
• at least 6 inches from any obstruction or hot surfaces
• with adequate air supply to prevent overheating and adequate
space to remove the pump for repair
• as close to the water source as possible to reduce piping
losses, e.g. open systems requiring suction lift.
Installation of pump and motors in areas where there are vapors,
gasses or dusts, flammable or combustible materials, subject to
fire or explosion, should be done in accordance with ABNT NBR,
NEC Art. 500, UL-674 standards and local codes. (UL = Under-
writers Laboratories, Inc.).
6.3 Connection
Arrows on the pump housing show the direction of flow of liquid
through the pump.
The pumps can be installed with the motor/pump shaft in all posi-
tions between vertical and horizontal, but the motor must never
fall below the horizontal plane.
Fig. 4 Permissible positions for pump and motor
Isolating valves should be fitted on either side of the pump to
avoid draining the system if the pump needs to be cleaned or
repaired.
TM03 1865 3305
Pos. Description Pos. Description
1 Type designation 5 Rated rpm
2Model, material number
and production code 6 Rated motor hp
3 Rated flow 7 Max. operating pressure
4Head in feet at rated
flow 8 Max. fluid temperature
2
36 47 5 8
1
Type
Model
Q
PHP
GPM H
PSI max
Feet n
Made in Brazil
981417
RPM
F° max
SR-F-20-16-B-2-60-BBVE-A
A 96292383 05 32
88
2
52
175
3500
176
Large pump motors (5 hp and up) are supplied with a
lifting eye which must not be used for lifting the
entire pump, e.g. by a crane or similar lifting equip-
ment.
TM03 1893 3305
TM03 1891 3305

5
6.4 Foundation
Grundfos recommends to install the pump on a concrete founda-
tion which is heavy enough to provide permanent and rigid sup-
port to the entire pump. The foundation must be capable of
absorbing any vibration, normal strain or shock. As a rule of
thumb, the weight of the concrete foundation should be 1.5 times
the weight of the pump.
Fig. 5 Example of a concrete foundation
Bolt hole dimensions are according to NEMA standard. Secure
the pump to the foundation using all four bolt holes. Uneven sur-
faces can result in pump base breakage when the mounting bolts
are tightened. (NEMA = National Electrical Manufacturers' Asso-
ciation).
To prevent vibrations from being transmitted to the building and
pipework, it is recommended to fit expansion joints and vibration
dampers.
Fig. 6 Expansion joints and vibration dampers on pump
6.5 Pipework in general
When installing the pipes, ensure that the pump housing is not
stressed by the pipework. The use of pipe compound or teflon
tape on all male threads (SR pumps) or a gasket (SF pumps) is
acceptable as a means of providing a positive seal at the pump
port conditions.
According to good installation practice, we recommend that:
• the system is thoroughly cleaned and flushed of all foreign
materials and sediment prior to pump installation
• the use of unnecessary fittings, valves or accessory items is
avoided, especially in the vicinity of the pump suction and dis-
charge ports
• the piping is adequately supported to reduce thermal and
mechanical stresses on the pump
• the pump is not installed at the lowest point in the system due
to the natural accumulation of dirt and sediment; if there is
excessive sediment or suspended particles present, we advise
you to use a strainer to prevent its entry into the pump
• all pipework is done in accordance with the recommendations
of the US Hydraulic Institute.
6.6 Suction piping
The suction pipe should be adequately sized and run as straight
and short as possible to keep friction losses to a minimum. Avoid
using unnecessary fittings, valves or accessory items.
Care should be taken to provide a means of pump isolation (e.g.
gate or butterfly valves) in applications where the pump is in a
pressurized or flooded suction condition.
If the pump is installed in a suction lift application, horizontal suc-
tion piping must rise gradually from the source to the pump and
contain no high spots which allow air pockets to form.
Fig. 7 Suction piping
6.7 Discharge piping
Before the pump is installed, we recommend that the discharge
piping is pressure-checked to at least the maximum pressure the
pump is capable of generating or as required by local codes and
regulations.
According to good installation practice, we recommend that:
• a check valve and isolation valve is installed in the discharge
pipe
• pipe, valves, and fittings are at least the same diameter as the
discharge pipe or sized in accordance with good piping prac-
tices to reduce fluid velocities and pipe friction losses.
Pipe, valves and fittings must have a pressure rating equal to or
greater than the maximum system pressure.
The standard discharge position for SR, SF pumps is vertical
(upward). To simplify pumping connections, however, the pump
housing may be rotated to optional positions in the field.
The pump housing can be rotated to any of four positions at
90-degree intervals as shown in fig. 8.
Fig. 8 Repositioning pump housing (viewed from suction
end)
Reposition the pump housing as follows:
1. Loosen and remove each of the nuts that attach the pump
housing to the pump head.
2. Carefully lift the pump housing off the pump head and rotate it
to the required position. Check that the O-ring is properly
seated.
3. Apply thread sealant, Loctite 567 or like, to the staybolt
threads.
4. Reinstall the nuts and tighten diagonally and evenly.
TM03 1895 3305
TM03 1892 3305
TM00 2263 3393TM03 1894 3305

6
6.8 Bypass
Note: The pump is not allowed to run against a closed discharge
valve as this will cause an increase in temperature/formation of
steam in the pump which may cause damage to the pump.
If there is any danger of the pump running against a closed dis-
charge valve, a minimum liquid flow through the pump should be
ensured by connecting a bypass to the discharge pipe. The
bypass line should feed back to the suction source.
A minimum flow rate equal to 10% of the flow rate at maximum
efficiency is needed at all times. Flow rate and head at maximum
efficiency are stated on the pump nameplate.
7. Electrical connection
7.1 Motor
The SR, SF pumps are supplied with heavy-duty, 2-pole
3450 rpm TEFC NEMA C-face motors selected to our rigid speci-
fications. Motors have been selected to operate without exceed-
ing their service factor ratings. Motors with other enclosure types
and for other voltages and frequencies are available on a special
order basis. Motors are commercially available NEMA frame.
Replace motors according to the motor nameplate data or contact
Grundfos to locate a motor supplier.
7.2 Supply power
1 x115/208-230 V ±10%
3 x 208-230/460 V ±10% or 3 x 575 V ±10%.
Check the electrical supply to make sure that the voltage, phase,
and frequency match that of the pump motor. The proper operat-
ing voltage, other electrical information and wiring diagrams can
be found on the motor nameplate.
Note: If voltage variations are larger than ±10%, do not operate
the pump.
7.3 Field wiring
Wire sizes should be based on the current carrying properties of
a conductor as recommended by the latest edition of the NEC,
local codes and regulations. Direct-on-line (DOL) starting is
approved due to the extremely fast run-up time of the motor and
the low moment of inertia of the pump and motor. If DOL starting
is not acceptable and reduced starting current is required, an
auto-transformer, resistant starter, or soft start should be used.
We recommend that a fused disconnect is used for each pump
where service and standby pumps are installed.
7.4 Motor protection
Single-phase motors
Single-phase SR, SF pumps are equipped with multi-voltage,
squirrel cage induction motors with built-in thermal protection.
Three-phase motors
SR, SF pumps with three-phase motors must be used with the
proper size and type of motor starter to ensure that the motor is
protected against damage from low voltage, phase failure, current
imbalance, and overloads. A properly sized starter with manual
reset and ambient-compensated extra-quick trip in all three legs
should be used.
The overload should be sized and adjusted to the current rating of
the motor.
Note: Under no circumstances should the overloads be set to a
higher value than the service factor current shown on the motor
nameplate. This will void the warranty.
Overloads for auto-transformers and resistant starters should be
sized in accordance with the recommendations of the manufac-
turer.
7.5 Pump start-up
Note: Do not start the pump before priming and venting the
pump. Never operate the pump dry.
7.5.1 Priming
The suction pipe and the pump must be filled with liquid before
the pump is started.
Closed system
1. Remove the topmost drain/vent plug.
2. Gradually open the isolation valve in the suction line until a
steady stream of airless water runs out of the open plug.
3. Replace the plug and securely tighten.
4. Completely open the isolation valves.
Open system
Filling with liquid is best accomplished through the discharge port
or an opening in the discharge piping at a level above the pump
volute.
1. Remove the topmost drain/vent plug.
2. Pour water into the discharge until the suction piping and
pump are completely filled.
If the suction piping does not slope downward from the pump
towards the water level, the air in the line must be purged
while the system is being filled.
3. Replace the drain/vent plug and securely tighten.
4. Connect and/or seal the discharge piping.
7.6 Check motor rotation
1. Make sure power is off.
2. Make sure that the pump has been filled and vented.
3. Rotate the pump shaft to be certain it turns freely.
4. Verify that the electrical connections are in accordance with
the wiring diagram on the motor.
5. Briefly switch the power on and observe the direction of rota-
tion. When viewed from the motor end, the pump should rotate
clockwise.
6. To reverse the direction of rotation, first switch off the supply
power.
7. On the three-phase motors, interchange any two power leads
on the load side of the starter. On single-phase motors, see
the connection diagram on the motor and change the wiring as
required.
8. Repeat step 3 to ensure that improper rotation has not
unthreaded the impeller from the pump shaft.
9. Switch on the power and again check the motor for proper
rotation.
All electrical work should be performed by a qualified
electrician in accordance with the latest edition of the
US National Electrical Code (NEC), local codes and
regulations.
The safe operation of this pump requires that it is
grounded in accordance with the NEC and local gov-
erning codes or regulations. Connectthe ground wire
to the grounding screw in the terminal box and then
to the acceptable grounding point.

7
7.6.1 Starting and adjusting
Before starting the pump, check the following:
1. The pump is primed.
2. The direction of rotation is clockwise when viewed from the
motor end.
3. All piping connections are tight and pipes are adequately sup-
ported.
4. The suction line isolation valve is completely open (if valve is
installed.
For initial starting, the isolation valve in the discharge pipe
should be closed and gradually opened after the pump is
turned on. Opening this valve too fast may cause water ham-
mering in the discharge pipe. Unless the discharge valve is
being used as a flow throttling device, make sure the valve is
completely open.
In addition:
5. Check and record the voltage and amperage of the motor.
adjust the motor overloads, if required.
6. Check and record operating pressures, if pressure gauges
have been installed.
7. Check all controls for proper operation. If the pump is con-
trolled by a pressure switch, check and adjust the cut-in and
cut-out pressures. If low-water-level controls are used, be sure
the low-water-level switch is properly adjusted so the pump
cannot run if the pump should break suction.
8. Operation and maintenance
8.1 Operation
Pump
The pumps are water-lubricated and do not require any external
lubrication or inspection.
Under no circumstances should the pump be operated for any
prolonged periods of time without flow through the pump.
This can result in motor and pump damage due to overheating. A
properly sized relief valve or bypass line should be installed to
allow sufficient water to circulate through the pump to provide
adequate cooling and lubrication of the pump bearings and seals.
Motor
Pump cycling should be checked:
• 1 hp to 5 hp: Max. 20 starts per hour
• 7.5 hp to 15 hp: Max. 15 starts per hour
• 20 hp to 40 hp: Max. 10 starts per hour.
Rapid cycling is a major cause of premature motor failure due to
increased heat build-up in the motor. If necessary, adjust controls
to reduce the frequency of starts and stops.
8.2 Maintenance
Pump
The pump is maintenance-free.
If the pump is to be drained for a long period of inactivity, inject a
few drops of silicone oil on the shaft between the motor stool and
the coupling. This will prevent the shaft seal faces from sticking.
Motor
The motor should be checked at regular intervals. It is important
to keep the motor clean in order to ensure adequate ventilation. If
the pump is installed in a dusty environment, the pump must be
cleaned and checked regularly.
Lubrication
The bearings of motors up to 15 hp are greased for life and
require no lubrication.
The bearings of motors of 15 hp and up must be greased in
accordance with the indications on the motor nameplate.
The motor should be lubricated with a polyurea-based grease
meeting the following specifications:
• NLGI grade 2
• Viscosity of basic oil: 115 cSt at 104°F (~ 40°C).
Temperature range: –22°F (~ –30°C) to 284°F (~ 140°C) during
continuous operation.
Do not over-grease the bearings. Over-greasing causes
increased bearing heat and can result in bearing/motor failure.
Preventative maintenance
At regular intervals, depending on the conditions and time of
operation,
• check that the pump meets required performance and is oper-
ating smoothly and quietly.
• check that there are no leaks, particularly at the shaft seal.
• check that the motor is not overheating.
• remove and clean all strainers or filters in the system.
• verify the tripping of the motor overload protection.
• check the operation of all controls; check control cycling twice
and adjust if necessary.
If the pump is not operated for unusually long periods, the unit
should be maintained in accordance with these instructions. In
addition, if the pump is not drained, the pump shaft should be
manually rotated or run for short periods of time at monthly inter-
vals.
If the pump fails to operate or there is a loss of performance, see
section 10.2.
8.3 Taking pump out of operation
Freeze-protection
Pumps which are not being used during periods of freezing
should be drained to avoid damage.
To drain the pump,
1. close the isolation valves
2. remove the drain/vent plugs at both the top and bottom of the
pump volute.
Do not replace the plugs until the pump is to be used again.
9. Service
If Grundfos is requested to service the pump, Grundfos must be
contacted with details about the pumped liquid, etc. before the
pump is returned for service. Otherwise Grundfos can refuse to
accept the pump for service.
Possible costs of returning the pump are paid by the customer.
Ensure that the escaping water does not cause injury
to persons or damage to the motor or other compo-
nents.
In hot-water installations, pay special attention to the
risk of injury caused by scalding hot water.
If a pump has been used for a liquid which is injuri-
ous to health or toxic, the pump will be classified as
contaminated.

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10. Troubleshooting
10.1 Preliminary tests
When working with electrical circuits, use caution to avoid electrical shocks. We recommend the use of rubber gloves and
boots.
Before starting any work on the pump, make sure that metal terminal boxes and motors are properly grounded. Failure to
ground the pump may result in serious electrical shock.
Supply voltage
TM03 1637 2505
How to measure What it means
Use a voltmeter (set to proper scale) to mea-
sure the voltage at the pump terminal box or
starter.
On single-phase units, measure between
power leads L1 and L2 (or L1 and N for
115 volt units).
On three-phase units, measure between:
• Power leads L1 and L2
• Power leads L2 and L3
• Power leads L3 and L1.
When the motor is under load, the voltage
should be within ±10% of the rated voltage.
Larger voltage variation may cause winding
damage.
Large variations in the voltage indicate a
poor electrical supply, and the pump should
not be operated until these variations have
been corrected.
If the voltage constantly remains high or low,
the motor should be changed to the correct
supply voltage.
Current measurement
TM03 1638 2505
How to measure What it means
Use an ammeter (set on the proper scale) to
measure the current on each power lead at
the terminal box or starter. See the motor
nameplate for amp draw information.
Current should be measured when the pump
is operating at constant discharge pressure.
If the amp draw exceeds the listed service
factor amps (SFA) or if the current imbalance
is greater than 5% between each leg on
three-phase units, check the following:
• Burned contacts on the motor starter.
• Loose terminals in starter or terminal box
or possible wire defect.
• Too high or too low supply voltage.
• Motor windings are shorted or grounded.
Check winding and insulation resistances.
• Pump is damaged causing a motor over-
load.
Insulation resistance
TM03 1639 2505
How to measure What it means
Turn off power and disconnect the supply
power leads in the pump terminal box. Using
an ohm- or mega ohmmeter, set the scale se-
lector to R x 100K and zero-adjust the meter.
Measure and record the resistance between
each of the terminals and ground.
Motors of all hp, voltage, phase and cycle
duties have the same value of insulation re-
sistance. Resistance values for new motors
must exceed 1,000,000 ohms. If they do not,
the motor should be repaired or replaced.

9
10.2 Troubleshooting chart
Fault Possible cause How to check How to fix
1. Pump does not run. a) No power at motor. Check for voltage at motor ter-
minal box. If no voltage at motor, check feeder panel for tripped circuits
and reset circuit.
b) Fuses are blown or circuit
breakers are tripped. Turn off power and remove fuses. Check for continuity with
ohmmeter.
Replace blown fuses or reset cir-
cuit breaker. If new fuses blow or
circuit breaker trips, the electrical
installation, motor, and wires
must be checked.
c) Motor starter overloads are
burned or have tripped out. Check for voltage on line and load side of starter. Replace burned heaters or reset. Inspect starter for other damage.
If heater trips again, check the
supply voltage and starter hold-
ing coil.
d) Starter does not energize. Energize control circuit and
check for voltage at the holding
coil.
If no voltage, check control cir-
cuit fuses. If voltage, check hold-
ing coil for shorts. Replace
defective coil.
e) Defective controls. Check all safety and pressure
switches for operation. Inspect
contact in control devices.
Replace worn or defective parts
or controls.
f) Motor is defective. Turn off power and disconnect
wiring. Measure the lead to
lead resistances with the ohm-
meter (R x 1). Measure lead to
ground values with ohmmeter
(R x 100K). Record measured
values.
If an open or grounded winding
is found, remove the motor and
repair or replace.
g) Defective capacitor (single-
phase motors). Turn off power and discharge capacitor. Check with ohmme-
ter (R x 100K).
When the meter is connected to
the capacitor, the needle should
jump towards “0” ohms and
slowly drift back to infinity. Re-
place capacitor if defective.
h) Pump is bound. Turn off power and manually
rotate pump shaft. If shaft does not rotate easily, check coupling setting and adjust
as necessary. If shaft rotation is
still tight, remove pump and in-
spect. Disassemble and repair.

10
2. Pump runs but at reduced
capacity or does not de-
liver water.
a) Wrong rotation. Check wiring for proper con-
nections. Correct wiring.
b) Pump is not primed or is
air-bound. Turn pump off, close isolation valve(s), and remove the prim-
ing plug. Check fluid level.
Refill the pump, replace the plug,
and start the pump. Long suction
lines must be filled before start-
ing the pump.
c) Strainer, check valve or
foot valve is clogged. Remove strainer, screen or valve and inspect. Clean and replace. Reprime the pump.
d) Suction lift is too large. Install compound pressure
gauge at the suction side of
the pump. Start pump and
compare reading to perfor-
mance data.
Reduce suction lift by lowering
the pump, increasing the suction
line size or removing high friction
loss devices.
e) Suction and/or discharge
piping leaks. Pump runs backwards when turned off. Air in suction pipe. Suction pipe, valves, and fittings must be airtight. Repair any
leaks and retighten all loose fit-
tings.
f) Pump is worn. Install pressure gauge, start
pump, gradually close the dis-
charge valve and read pres-
sure at shut-off.
Convert PSI to feet (Measured
PSI x 2.31 ft. / PSI = ____ft.) Re-
fer to the specific pump curve for
shut-off head for that pump
model. If head is close to curve,
pump is probably OK. If not, re-
move pump and inspect.
g) Pump impeller or connec-
tion port is clogged. Disassemble and inspect pump passageways. Remove any foreign materials found.
3. Pump cycles too much a) Pressure switch is not
properly adjusted or is de-
fective.
Check pressure setting on
switch and operation. Check
voltage across closed con-
tacts.
Readjust switch or replace if de-
fective.
b) Level control is not prop-
erly set or is defective. Check setting and operation. Readjust setting (refer to level control manufacturer’s data). Re-
place if defective.
c) Insufficient air charging or
leaking tank or piping. Pump air into tank or dia- phragm chamber. Check dia-
phragm for leak. Check tank
and piping for leaks with soap
and water solution. Check air
to water volume.
Replace as necessary.
d) Tank is too small. Check tank size and air volume
in tank. Tank volume should be
approximately 10 gallons for
each gpm of pump capacity.
The normal air volume is 2/3 of
the total tank volume at the
pump cut-in pressure.
Replace tank with one of correct
size.
e) Pump is oversized. Install pressure gauges on or
near pump suction and dis-
charge ports. Start and run
pump under normal conditions,
record gauge readings.
Convert PSI to feet (Measured
PSI x 2.31 ft. / PSI = ____ft.) Re-
fer to the specific pump curve for
that model. Ensure that total
head is sufficient to limit pump
delivery within its design flow
range. Throttle pump discharge
flow is necessary.
Fault Possible cause How to check How to fix

11
11. Disposal
This product or parts of it must be disposed of in an environmen-
tally sound way.
Use the public or private waste collection service.
4. Fuses blow or circuit
breakers or heaters trip a) Low voltage. Check voltage at starter panel and motor. If voltage varies more than ±10%, contact power company.
Check wire sizing.
b) Starter overloads are set
too low. Cycle pump and measure am- perage. Increase heater size or adjust trip setting to a maximum of mo-
tor nameplate (full load) current.
c) Three-phase current is im-
balanced. Check current draw on each lead to the motor. Must be within ±5%. If not, check motor and wiring. Rotating all
leads may eliminate this prob-
lem.
d) Motor is shorted or
grounded. Turn off power and disconnect wiring. Measure the lead-to-
lead resistance with an ohm-
meter (R x 1). Measure lead-
to-ground values with an ohm-
meter (R x 100K) or a mega-
ohmmeter. Record values.
If an open or grounded winding is
found, remove the motor, repair
and/or replace.
e) Wiring or connections are
faulty. Check proper wiring and loose terminals. Tighten loose terminals. Re- place damaged wire.
f) Pump is bound. Turn off power and manually
rotate pump shaft. If shaft does not rotate easily, check coupling setting and adjust
as necessary. If shaft rotation is
still tight, remove pump and in-
spect. Disassemble and repair.
g) Defectivecapacitor(single-
phase motors). Turn off the power and dis- charge the capacitor. Check
with ohmmeter (R x 100K).
When the meter is connected to
the capacitor, the needle should
jump towards “0” ohms and
slowly drift back to infinity. Re-
place if defective.
h) Motor overloads at higher
ambient temperature than
motor.
Use a thermometer to check
the ambient temperature near
the overloads and motor.
Record these values.
If ambient temperature at motor
is lower than at the overloads,
especially where temperature at
overloads is above 104°F ambi-
ent-compensated heaters should
replace standard heaters.
Fault Possible cause How to check How to fix
Subject to alterations.

U.S.A.
GRUNDFOS Pumps Corporation
17100 West 118th Terrace
Olathe, Kansas 66061
Phone: [phone]
Telefax: [phone]
Canada
GRUNDFOS Canada Inc.
2941 Brighton Road
Oakville, Ontario
L6H 6C9
Phone: [phone]
Telefax: [phone]
Mexico
Bombas GRUNDFOS de Mexico S.A. de C.V.
Boulevard TLC No. 15
Parque Industrial Stiva
Aeropuerto
Apodaca, N.L. 66600
Mexico
Phone: [phone]
Telefax: [phone]
Addresses revised 18.04.2002

www.grundfos.com
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Thinking ahead makes it possible
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96600184 0805 US