Maintaining Irrigation Pumps, Motors, and Engines

1. Maintaining Irrigation
ATTRA Pumps, Motors, and Engines
A Publication of ATTRA - National Sustainable Agriculture Information Service • 1-800-346-9140 • www.attra.ncat.org
By Mike Morris and This publication explains how to maintain irrigation pumps, motors, and engines for peak efficiency.
Vicki Lynne The publication includes descriptions and diagrams of recommended installations, checklists for main-
NCAT Energy tenance tasks, and a troubleshooting guide. Each system component is treated separately and main-
Specialists tenance tasks are broken down by how frequently they need to be done. References and resource list-
© 2006 NCAT ings follow the narrative.
Contents Introduction
Introduction ..................... 1
Efficient irrigation begins with properly
Recommended installed and maintained pumps, motors,
Installations ...................... 1
Centrifugal Pump ....... 1
and engines.
Turbine Pump .............. 2 Equipment problems and management
Control Panel ............... 2
problems tend to go hand in hand. Equip-
Pumping Plant ment that is badly designed or poorly
Maintenance .................... 3
Electric Motors ............ 3 maintained reduces the irrigator’s degree
Control Panel ............... 5 of control over the way water is applied.
Engines .......................... 6 Problems like patchy water distribution
Centrifugal Pumps ..... 8 and inadequate pressure make it impos-
Turbine Pumps .......... 12
sible to maintain correct soil moisture lev-
Troubleshooting ........... 13 els, leading to crop stress, reduced yields,
References ...................... 15 wasted water, runoff, soil erosion, and
many other problems.
NCAT photo
Recommended Installations
the pumping plant might look like Fig. 1,
Centrifugal Pumping Plant Poor, on the discharge side. The next time
Installation with Electric Motor you rebuild the pump, replace the fittings so
The term “pumping plant” refers to the irri- that your system will look like Fig. 1, Ideal.
gation pump and motor or engine, consid-
An ideal installation should also have:
ered together. If you have an older system,
A discharge concentric expansion
Figure 1. Ideal and Poor Installations instead of an abrupt change in pipe
IDEAL Discharge pressure
diameter, to minimize head loss,
Concentric
expansion Shut-off valve
gauge with ball valve
Discharge pipe
turbulence, and air pockets.
larger than pump
discharge size
A discharge valve the same diam-
ATTRA—National Sustainable eter as the mainline.
Agriculture Information Service
is managed by the National Cen- Check
Flexible joint permits some
misalignment and axial
Pipe
support Fig. 2 shows what your pumping plant
ter for Appropriate Technology
valve movement; resolves most
thermal expansion problems should look like when pumping from a
(NCAT) and is funded under a
grant from the United States POOR
Valve too
small surface source such as a river or canal.
Department of Agriculture’s The pumping plant should also have:
Rural Business-Cooperative Ser-
vice. Visit the NCAT Web site
(www.ncat.org/agri. Sudden
On the Suction Side of Pump:
expansion
html) for more informa-
tion on our sustainable (Adapted from Saving Energy on Montana Farms and Ranches, A well designed and screened sump
agriculture projects. Montana Department of Environmental Quality.) that keeps trash away.

2. Suction line joints that are airtight On the Discharge Side of Pump:
under a vacuum.
A valve size that is the same diam-
No high spots where air can collect. eter as the mainline.
Related ATTRA
Publications A suction line water velocity of five A non-slam check valve to pre-
feet per second (fps) or less; two to vent back spin when shutting off
Energy Saving Tips for
Irrigators
three fps is best. the pump.
The Montana A suction entrance at least two pipe An air relief device when a buried
bell diameters from sump inlet.
Irrigator’s Pocket mainline is used.
Guide A suction lift (vertical distance from
A discharge line water velocity of
Drought Resistant Soil water surface to pump impeller) less
than 15 to 20 feet. less than seven fps. Five fps is best.
Drought Resource
Guide An eccentric reducer to keep air An energy efficient 1800 rpm motor
Soil Moisture from becoming trapped in the with a 15 percent safety factor.
Monitoring: Low-Cost reducer fitting. A simple shade over the motor.
Tools and Methods
A vacuum gauge to indicate whether
Measuring and the primer is pulling a vacuum or Turbine Pump Installation
Conserving Irrigation
Water
just moving air through the pump. Refer to the left half of Fig. 3 for a prop-
erly installed turbine pump in a well; many
of these same principles apply to turbine
Figure 2. Recommended Pump Installations, Top and Side Views pumps in sumps. The properly constructed
well should also:
Top View
Be at least six inches in diameter
Solid Gradually increasing larger than the outside diameter of
tapered section
foundation
the well casing when a gravel pack
Sump volume at least
twice maximum gpm is required.
Inlet
All joints
Have horizontal well screen slots
Cone increaser
water tight Uniformly distributed flow
that continue below the pumping
placed at pump Pressure
outlet if required gauge o
45 maximum
water level. The openings should
Supports as hold back at least 85 percent of the
Straight run of at least
10 pipe diameters “D”
or straightening vanes
required
surrounding material.
for testing flow
The poorly constructed well in the lower
Check
valve right half of Fig. 3 shows a well casing that
Shut-off
valve
is not centered in the well. Vertical slotted
pipe perforations are above the minimum
Primer Straightening vanes or
Side View water level, creating cascading water.
straight run as short as
possible but not less than
Globe 6 pipe diameters “D”
isolation
valve Vacuum
gauge
1/4” per foot
minimum upward
Grating, bar racks
Control Panel for Electric Motors
slope to pump
and screens at
beginning of The importance of a properly installed
Smooth
long-radius
maximum width
section control panel cannot be overemphasized
elbows
for personal safety and for protecting your
investment in your pump and motor.
Minimum water
Your control panel should:
Anchor Pipe supports “D”
(as required) level
Drainage
bolts Eccentric 4 “D” Minimum
inlet
Inlet
away from reducer minimum
motor
Suction bell
turbulence
Have a shade over it to keep
As close as
Inlet below
minimum “D” = pipe
thermal breakers cool.
“D” minimum water level diameter
possible
Be mounted on secure poles
(Adapted from Energy Efficient Pumping Standards, Utah Power & Light Company.) or foundation.
Page 2 ATTRA Maintaining Irrigation Pumps, Motors, and Engines

3. Figure 3. Deep Well Turbine Pump
Pump motor
RECOMMENDED
Sounding tube Discharge pipe
access
Grout seal
Casing centered in hole
with 3 spacers @ 40’
intervals
Pumping
water
level
Static water
level
Drawdown less NCAT photo
than 60% of water
depth
Pump housing Pumping Plant Maintenance
Air line
Every irrigation system needs regular
maintenance in order to run effi ciently
and reliably. Poorly maintained systems
waste energy and money, and are prone
to breakdowns that cause crop losses and
Excess pumping rate;
drawdown more than yield reductions.
60% of water depth
NOT RECOMMENDED Caution: The recommendations
below are not comprehensive and
(Adapted from Energy Efficient Pumping Standards, Utah
Power & Light Company.)
may not be correct for all systems.
Consult your owner’s manual for rec-
ommended maintenance procedures
and always follow the manufactur-
Have any missing knockout plugs er’s instructions if they differ from the
and other holes in the starting switch ones in this guidebook.
box replaced and screened or puttied
against rodents, insects, and dirt.
Electric Motor Maintenance
Have a small hole (3/16-inch diam-
eter) in the bottom of the panel to General
allow moisture to drain. Make a habit of checking that the motor is
Your control panel should include the securely bolted to its platform. Mounting
following controls at a minimum: bolts can vibrate loose. Check to see that
rotating parts aren’t rubbing on station-
Circuit breaker(s) for overload currents. ary parts of the motor, causing damage to
Lightning arrester. the motor.
Surge protector. Remember that an electric motor is an
air-cooled piece of equipment and needs
Phase failure relay, to protect the
all the ventilation it can get. Excessive
motor from phase reversal or failure
heat is a main cause of reduced motor life.
and from low voltage.
Motors also like to be dry. Keep motor
A pressure switch to shut off the windings dry by keeping pump packing
motor if pumping pressure drops to in good condition. Even if windings are
undesirable levels. protected from moisture, minerals in the
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4. pumped water can attach arcing at electrical terminals. The voltage
to the windings and cause drop across loose connections will cause
early failure. the motor to operate at less than its rated
voltage, increasing internal motor tempera-
Motors that operate at
ture. Increased heat will break down motor
3600 rpm experience twice
winding insulation, resulting in electrical
as much wear as motors
shorts and motor failures. A loose or bro-
operating at 1800 rpm.
ken connection can also unbalance the
Regular maintenance is
phases of three-phase power and damage
especially critical for 3600
the motor windings.
rpm motors and pumps.
NCAT photo Caution: Before conducting these
Maintenance Tasks tasks, be sure power is off at the util-
At season startup: ity disconnect switch. It may be neces-
sary to have the utility company shut
Remove tape on all openings
the power off.
and clean out rodents, insects,
or debris.
Maintenance Tasks
Locate the motor drain hole on At season startup:
the base or support for the base,
and clean it out so water won’t be Inspect insulation of motor wind-
trapped and held directly under the ings. If the windings are excessively
air intake. grease-covered, consult your motor
repair shop for direction.
Change oil in reduced voltage start-
ers, using an oil recommended by Check all safety switches according
the manufacturer. Be sure to clean to the manufacturer’s directions.
the oil pan before refi lling. Twice a year:
Use vacuum suction or air pressure Check electrical connections from
to remove dust and debris from meter loop to motor for corrosion
moving parts of the motor. (Don’t and clean if necessary. Coat the
exceed 50 psi of air pressure.) wiring (especially aluminum) and
Periodically: connectors with an antioxidant that
Clean grass or debris from air ven- meets electrical code requirements.
tilation openings on the motor and Check electrical connections from the
from around the motor to allow a meter loop to the motor for tightness.
full flow of cooling air. Tighten and re-tape if necessary.
Check screens on motor ventilation Replace overheated connections or
openings. Replace with machine wires with new material. Overheated
cloth (¼-inch mesh) as necessary. connections will show heat damage
such as burnt insulation on wires.
At end of season shutdown:
Cover the motor with a breathable Motor Bearings
water-resistant tarp. Lubricate the motor according to the man-
ufacturer’s instructions. Intervals between
Motor Electrical System lubrication will vary with motor speed,
Wide temperature fluctuations during the power draw, load, ambient temperatures,
year can cause electrical connections (espe- exposure to moisture, and seasonal or con-
cially in aluminum wire) to expand and tinuous operation. Electric motors should
contract, loosening connectors. Loose elec- not be greased daily. Bearings can be
trical connections cause heat buildup and ruined by either over- or under-greasing.
Page 4 ATTRA Maintaining Irrigation Pumps, Motors, and Engines

5. Fill a grease gun with electric motor bearing
grease and label it so it won’t be confused
with other types of lubricating grease.
Caution: Lubrication instructions in
owner’s manuals should be followed
if they differ from these. Newer motors
may have sealed bearings that cannot
be lubricated.
Recommended Re-greasing Periods for Motors
Horsepower Range
Type of Service 1-9 10-40 50-150
Normal Duty
8 mos. 6 mos. 4 mos. NCAT photo
(8-hour day)
Heavy Duty
4 mos. 3 mos. 2 mos. a small amount of grease from the
(24-hour day)
grease port to allow for grease expan-
sion during full load operation.
Maintenance Tasks Replace grease plug.
Change the grease at recommended inter- Control Panel Maintenance
vals to remove any accumulated moisture:
Control Panel Safety Precautions
Remove the bottom relief plug and
clean hardened grease out of pas- Never use the main disconnect to start or
sageway. stop your motor. It is not intended for this
purpose. Using the main disconnect to start
Using a grease gun, fi ll the hous- and stop the motor will cause excessive
ing with approved high tempera- wear of the contacts and arcing can occur.
ture electric motor bearing grease Use the start and stop button.
(refer to the manufacturer’s manual
for API number of grease) until old If the overhead lines to your control panel’s
grease is expelled. service are obstructed by tree branches or
other items, have the utility company clear
Caution: If old grease is not expelled the lines.
as the new grease is pumped in, stop
adding grease and have your motor Have an electrician inspect your panel to
checked by a qualified repair person. ensure that:
Adding new grease without old grease Control circuits are protected with
being removed could blow the seals the correct size and type of fuse.
and push grease into the motor wind-
Lightning arresters are properly
ings, causing the motor to overheat
installed on the meter and motor
and reducing its service life. Do not
side of the buss and breaker. They
over-grease your motor. should also be mounted in a secure
Run motor until all surplus grease box to protect you if they blow up.
is thrown out through the bottom The service panel is properly
grease port (may require 5 to 10 grounded, independently of the
minutes). pumping plant.
Shut off the motor and use a screw- Service head grommets are in place
driver or similar device to remove and in good condition.
www.attra.ncat.org ATTRA Page 5

6. General Maintenance If easily accessible, check magnetic
starter switch contact points.
Have your electrician or pump maintenance
person do a Megger check on the control Periodically clean out debris, rodent
panel, motor, conduits, and other electri- droppings, and nests and insects.
cal connections. The Megger device applies Make sure drain hole is open.
a small amount of voltage to an electrical At end of season shutdown:
component and measures the electrical
resistance. A Megger test can also detect Ensure that switches are in the off
potentially harmful moisture in windings. or open position. Lock the panel
in the off position and remove the
Any time the main disconnect switch has
fuses to prevent accidental startup
been left open or off, operate it several times
and vandalism. Removing fuses will
before leaving it closed or on. Copper oxide
also prevent corrosion.
can form in a few hours and result in poor
contact and overheating. Any type of corro- Protect exposed control boxes
sion can cause poor contact, poor ground- against moisture and dust with a
ing, and direct or high-resistance shorts. waterproof tarp.
E
ngine power
Caution: After opening the control
is affected by panel but before touching the con- Engine Maintenance — Diesel,
altitude and trols inside, use a voltmeter to be Gasoline, Liquid Propane Gas
air temperature. sure that the incoming power is dis- (LPG), and Natural Gas
connected or turned off. If neces-
Make a habit of checking that the engine
sary, have your utility disconnect the
is securely bolted to its platform; mount-
power. If you have any doubts about
ing bolts can vibrate loose. Regularly check
the safety of your control panel,
coolant, oil levels, fuel, and fan belts. If
WALK AWAY AND CALL A QUALI- coolant or oil is down, check lines for leak-
FIED ELECTRICIAN. Even a current age. On diesel engines, check injectors and
of 15 milliamps (one milliamp is one fuel lines for leaks.
one-thousandth of an amp) can cause
serious injury or death. Always play Engine power is affected by altitude and air
it safe! temperature. Derate engine power output by
3.5 percent for every 1,000-foot increase
Maintenance Tasks in altitude over 500 feet above sea level.
At season startup: Derate output by 1 percent for each 10-
degree increase in air temperature above
Replace fuses after checking to see
that they aren’t blown. Never use 85 degrees F.
oversized fuses.
Engine Startup
Operate disconnect switch slowly
to check for alignment of blades (Beginning of Season)
and clips. Maintenance Tasks
Open and close the disconnect Remove tape on all engine open-
switch several times to clean oxide ings and the distributor cap, and
from contact points. tighten belts.
Clean contacts of all dust and dirt. Charge batteries and connect them.
Clean copper contacts with very fine
Open fuel tank shutoff valve.
sandpaper or a fi ne fi le. Replace
badly pitted or burned contacts. Before starting the engine, override
Never fi le silver or silver-plated con- safety switches that protect against
tacts. Leave contacts clean and dry low water pressure, loss of oil pres-
so dust won’t collect. sure, and overheating. After engine
Page 6 ATTRA Maintaining Irrigation Pumps, Motors, and Engines

7. has reached operating speed, Inspect breaker points for wear and
activate the safety switches. replace if needed.
Run the engine for 10 minutes, Set the gap or dwell angle and
then turn it off and check oil and lubricate the rotor.
coolant levels.
Check timing and adjust if necessary.
Check engine and pump for any
Clean all connecting terminals;
leaks caused by drying gaskets.
cover with protectors.
Engine Air System Spray silicone on electrically oper-
Always replace disposable air fi lters with ated safety switches and ignition
new ones. Cleaning can distort the fi lter and system to prevent corrosion.
allow more dirt to enter. Twice a year:
Maintenance Tasks In engines that have them, clean
At season startup, clean and refi ll and re-gap spark plugs or replace
the fi lter bath in oil-bath air clean- with plugs in the recommended heat
ers and reassemble the air cleaner. range.
Periodically brush blockage off the Check all terminals and electrical
screen if the air induction system is
connections for tightness and corro-
equipped with a pre-screener.
sion, and spray with corrosion inhibi-
Change the air fi lter when the ser- tor (NOT grease).
vice indicator signals that it’s time
Remove the distributor cap and
to change it:
lubricate governor weights with sili-
• Turn off engine before changing cone (NOT oil).
air fi lter.
• Wipe the outside of the cover and Engine Oil and Lubrication
housing with a damp cloth and Have a sample of engine oil analyzed for
remove the cover. contaminants, which signal abnormal wear.
• If cover is dented or warped, Intervals between analyses will depend on
replace it. the engine, and analysis may be cost-effec-
tive only for larger engines. Equipment deal-
• Use extreme care when remov- ers should know where the oil can be ana-
ing the fi lter to prevent dirt from lyzed and how often this should be done.
falling into the intake duct. Use a
clean damp cloth to wipe inside
of fi lter housing.
• Install new air fi lter.
Engine Electrical System
If you have a natural gas engine, be aware
that natural gas has a higher octane value
than automotive gasoline. You can increase
engine efficiency and reduce fuel consump-
tion by setting the ignition timing to take
advantage of the higher octane. Consult the
engine manufacturer for recommendations
on how to do this.
Maintenance Tasks
At season startup: NCAT photo
www.attra.ncat.org ATTRA Page 7

8. Use only the oil recommended by the manufac- Remove spark plugs. Pour a table-
turer. Tag each engine with a label identifying spoon of clean motor oil into each
the proper oil. spark plug hole. Position spark plug
wire away from cylinder opening
Maintenance Tasks and rotate crankshaft by hand to
Twice a year: lubricate piston and rings. Replace
spark plug.
If the engine was not protected
during shutdown, or if the oil has Seal the distributor cap with duct
not been changed within the last tape where the cap joins the dis-
year, change the crankcase oil and tributor housing.
oil fi lter. Seal all the openings in the engine
Lubricate all engine accessories with duct tape, including air cleaner
such as the driveshaft and U-joints. inlet, exhaust outlet, and crankcase
breather tube.
Engine Fuel and Coolant If the engine coolant is water,
drain and refi ll the cooling system
D
Maintenance Tasks
o not store with water, a rust inhibitor, and
Twice a year remove and clean or antifreeze.
batteries
replace the fuel fi lter.
directly Remove tension from belts.
Periodically check that fuel tank cap
on concrete.
and oil fi lter cap are on tight and Remove and store batteries in a cool
that gaskets aren’t cracked. but not freezing location. Do not
store batteries directly on concrete.
Periodically check that the fluid
level and degree of coolant protec- If engine is outside, cover with a
tion are adequate. Check that the water-resistant tarp.
radiator cap is on tight and that gas-
kets aren’t cracked. Centrifugal Pump Maintenance
Centrifugal Pump Startup
Engine Shutdown (End of Season)
(Beginning of Season)
Maintenance Tasks
Maintenance Tasks
Drain all fuel from the tank and
lines and shut off the fuel valve. If Using new gaskets and pipe-dope,
LP gas is used, drain vaporizer- reconnect to the pump any piping
regulator. (Drain both fuel and removed during shutdown.
water lines.) Re-install the primer and priming
valve if they were removed during
shutdown.
Figure 4. Centrifugal Pump and Motor
Check that the pump shaft turns
freely and is free of foreign objects.
Applying power could break the
impeller if it’s rusted to the case.
Check the pump for leaks caused by
drying gaskets.
Check intake and discharge pip-
ing for proper support and make
sure the pump is securely bolted to
the platform.
Clean the drain hole on the under-
side of the pump.
Page 8 ATTRA Maintaining Irrigation Pumps, Motors, and Engines

9. General
To avoid water leaks, make sure that all gas-
kets are the correct ones for the coupling or
flange. Eliminate air leaks in your pump’s
suction line by coating threaded connections
with pipe cement or white lead and drawing
them tight. Also examine suction line welds
for cracks, which will allow air leaks.
Choosing Gaskets
Using a gasket in a coupling that it was not
made for is a common cause of leaky gaskets.
Get the right gasket and the right kind of gas-
ket for the fitting.
Flat gaskets: Most are made of neoprene and
are used on flanged, bolt-together fittings.
They are usually not expensive. They normally NCAT photo
fail by “creeping” out of their fitting. Look for
connections between pump and primer. On
new neoprene gaskets that contain a cotton
backing sandwiched in the gasket to reduce
a hand primer, if grass or other debris is
the creeping action. lodged in the check valve, air is pulled back
into the pump at every stroke and the pump
Shaped gaskets: The three most common won’t prime. After proper priming, fi ll the
materials are styrene-butadiene (SBR), eth-
system slowly.
ylene-propylene (EPDM), and polyethylene
(poly). SBR and EPDM have much better resis- Maintenance Tasks
tance to cracking, abrasion, ozone, and weath-
Twice a year:
ering resistance than poly gaskets. They are
more expensive than poly but will last longer. Thoroughly clean suction and dis-
When buying shaped gaskets, look for gaskets charge piping and connections,
that are dull; this indicates that little or no plas-
removing moss and debris.
ticizer has been added to the gasket. Plasticiz-
ers significantly reduce gasket life. Tighten all drain and fi ll plugs in
the pump volute case to avoid air
and water leaks. Use a pipe thread
If your pump isn’t delivering water, verify compound on all pipe threads. Figure 5. Impeller Eye
that the pump shaft is turning in the direction Check for cracks or holes in the and Wear Ring
of the arrow on the pump casing. As viewed pump case.
from the motor end, the rotation is usually
clockwise, but check the startup instructions Clean trash screening device and
that came with the pump. On three-phase screens on the suction pipe.
motors, swap any two power leads to change Impeller
rotation. It is recommended that a qualified Servicing Impeller and Wear Rings
electrician perform this task. If you suspect that your pump impeller is
clogged or damaged, or that the wear rings
If the pump doesn’t prime, check for air
are worn, you can dismantle the pump. This 1/32” clearance
leaks on discharge valves. Many all-metal
will take some work and is best done in the
gate-type valves won’t seal properly to cre-
shop. Or have a qualified pump repair shop
ate a vacuum. Sand or other debris lodged
undertake this procedure. Always follow
between the rubber flap and the valve seat
the directions in the manufacturer’s man-
will prevent check valves from sealing and
forming a tight joint. See if the rubber face ual, if available, instead of the following
is cracked or chipped and not seating. simplified directions.
Replace the gate valve or check valve. Check Remove suction cover or volute case.
www.attra.ncat.org ATTRA Page 9

10. dirt, silt, or sand in the water can also score
Net Positive Suction Head (NPSH) and Cavitation the sleeve.
Many people are surprised to learn that centrifugal pumps don’t pull Check for an improperly greased or worn
water through a suction pipe; they can only pump water that is delivered
rotary shaft seal by running the pump and
to them. When air is removed from the suction pipe by a primer pump,
the weight of the earth’s atmosphere forces water to rise into the pipe, squirting oil on the shaft just outside the seal.
delivering water to the pump. Oil drawn into the seal indicates a leak.
Even in the best of circumstances (including a near-perfect vacuum), If the pump has been out of service, the
the maximum water column that can be forced by atmospheric pressure packing may be dried and hardened. Air
never exceeds about 33 feet in height. As elevation, water temperature, can leak into the pump through the packing
and pipe friction increase, the height of the water column that can be box and the pump can lose prime.
forced drops. The maximum column of water that can be created in a
pipe under a given set of conditions is known as Net Positive Suction
Head or NPSH. Maintenance Tasks
Insufficient NPSH often occurs at startup. Since the pump is working Grease the packing box annually with a
against low pressure, it pumps a larger volume than in normal opera- proper pump packing grease. Less frequent
tion. This larger volume creates friction losses in the suction line, reduc- maintenance causes grease to harden, mak-
ing NPSH. Too little available NPSH can result in vaporization of water ing this task very difficult.
in the eye of the impeller, causing cavitation, a noisy condition where
vapor bubbles collapse violently in the pump. If the packing box is equipped
with a grease cup or a grease zerk,
To stop cavitation, close the discharge valve. If cavitation is allowed
to continue, the impeller and pump casing can become pitted and
apply a couple pumps of pack-
damaged, reducing pump capacity. To eliminate cavitation as well ing grease to the packing box to
as water hammer, and to prevent high amperage draw on demand force out the remaining water and
meters, open the discharge valve slowly to fill the mainline whenever protect the packing.
you start up the pump. For a packing box without a grease
Caution: Don’t let the pump run more than two minutes with the discharge cup or zerk, remove the last two
valve closed. packing rings (see below for replac-
ing packing) and discard. Pack
Remove debris from impeller and packing grease into the packing box
volute. Remove pebbles lodged until full. Add two new rings and
between vanes. gently tighten the packing gland
slightly to force the grease into the
Check wear at the impeller eye and subsequent packing rings. Then
vanes. If worn, repair or replace the loosen the gland.
impeller.
Re-machine or replace wear
ring if clearance is greater Figure 6. Pump Packing
than 1/32 inch per side.
Replace suction cover or
volute. Use a new gasket.
Servicing the Pump Packing
A pump with shaft sleeve and pack-
ing in good condition and properly
adjusted shouldn’t require con-
stant re-adjustment, but should be
checked daily. Unless proper leak-
age (about 8 to 10 drops per minute)
is running through the packing box,
the packing will become overheated
and dry out, eventually burning and
scoring the shaft sleeve. Excessive
Page 10 ATTRA Maintaining Irrigation Pumps, Motors, and Engines

11. Replacing the Packing Successive rings of packing should
be installed so the joints are 120
Old packing should be replaced completely
degrees apart.
if leakage cannot be reduced by adding
a new packing ring to the old packing, or Install lantern ring (if required) in
if the packing is burned (dried up and proper position to the packing rings as
scorched) or has leaked excessively during shown on your manual’s parts page.
the season. Install packing gland so that it just
Caution: This task is difficult. Have begins to enter the stuffing box
a qualified pump repair shop do it if straight, making sure that the full
you are in doubt. If you are attempt- packing is under uniform pressure.
ing the procedure yourself, do it in Seal the gland with clip, stud,
the shop rather than in the field. and nut.
Remove packing box gland nut If the packing is equipped with a
with a wrench. Remove the gland grease fitting, add a shot of grease.
and packing. Before inserting the last two packing
O
To remove packing, twist two pack- rings on boxes without a grease cup nce the
ing pullers 180 degrees apart into or zerk, pack grease into the pack- packing is
the exposed packing ring. Pull each ing box until full. Add the last two
ring out of the packing box cav- burned and
rings and tighten the packing gland
ity until all are removed. The lan- slightly to force the grease into the the shaft sleeve is
tern ring has two holes 180 degrees subsequent rings of packing. Then scored, no amount
apart and can be removed with the loosen the gland. of adjustment will
packing pullers. Start the pump with the packing maintain proper
Replace the shaft sleeve if it is worn gland loose so there will be initial leakage for any
or grooved. This usually requires leakage. Tighten the packing gland length of time.
pump disassembly. Once the pack- only enough to draw the necessary
ing is burned and the shaft sleeve vacuum for priming.
is scored, no amount of adjustment
Tighten the gland nuts slightly and
will maintain proper leakage for any
evenly every 15 to 20 minutes, until
length of time.
leakage is reduced to about 8 to
Before replacing new packing, 10 drops per minute and the water
insert the packing gland to make leaking from the box is cool.
sure it enters freely to the gland’s
Caution: Don’t stop leakage entirely.
full depth. If it doesn’t, clean out the
fragments of old packing and other
debris that may be obstructing it. Centrifugal Pump Shutdown
Install new packing rings as far for-
(End of Season)
ward as can be reached. Install only In cold climates, it is critical that all
the type and size of packing recom- water be drained from pumps prior to
mended by the manufacturer. freezing weather.
Insert each ring separately. Push
Maintenance Tasks
it securely into the box and seat it
fi rmly. A small amount of packing Remove suction and discharge piping
grease applied to the packing will in areas where ice is a problem. Make
make this job a little easier. Don’t sure drain valves are not plugged,
use sharp points to push the pack- and drain water from the pump.
ing into the box. (Use the packing Cover any exposed metal, such as
gland, a wooden dowel, pliers han- the shaft, with protective lubricant
dle, fi ngers, or other blunt object.) to prevent corrosion.
www.attra.ncat.org ATTRA Page 11

12. Cover all oil- or grease- Maintenance Tasks
lubricated bearings At season startup:
with lubricant so mois-
ture won’t rust and Change the oil in the oil bath or
pit them. reservoir for the pump upper bear-
ings. Fill with approved turbine oil
Remove tension from almost to the top of the sight glass
any belts.
so bearings are covered, taking
Open petcock and care that excess oil doesn’t get on
drain diaphragm-type or in the motor.
NCAT photo
hand primer.
Periodically:
If the discharge primer valve is
equipped with a rubber seat, coat it Grease lower bearings. Refer to
with rubber preservative. electric motor bearing greasing
Any rubber parts in a flexible cou- instructions above, on page 5.
pling connecting the pump to the Maintain the pump packing on water-
driver should also receive a coating lubricated turbine pumps as directed
of preservative. above on pages 10 to 11 for centrifu-
Make sure the ball valve on the gal pump packing.
pressure gauge riser is closed.
Annually:
Remove the pressure gauge and
store inside. Change the bearing oil in vertical
hollow shaft motors. When replacing
Seal all openings, including suc-
tion, discharge, and primer, with the oil, follow motor manufacturer’s
duct tape, to keep out rodents and recommendations or use ISO-VG32
foreign material. turbine oil, such as:
Cover the pump with a water- Mobil DTE 797
proof tarp. Lubriplate HO-0
Turbine Pump Maintenance Chevron Turbine Oil GST32
Shell Turbo T Oil 32
General
Figure 7. Oil-Lubricated Turbine Pump
Some of the instructions Maintain bearing oil at the proper level.
below also apply to sub- Overfi lling the oil reservoir can cause oil
mersible pumps. to overflow when the motor heats up during
operation. The excess oil will adhere to the
Make a habit of periodi- motor and to ventilation screens, collecting
cally checking that dis-
dirt and debris and reducing the motor’s
charge piping is firmly
ability to dispel heat.
supported in the area
near the pump. Make
sure the pump is securely Short-Coupled Turbine Pump
bolted to the platform.
Maintenance Tasks
If your turbine pump At season startup for oil-lubricated pumps:
is installed over a well
and you’ve experienced Fill the oil reservoir and start the oil
water supply problems, flowing to the pump one hour before
check the static level and starting the pump. Check to see that
drawdown in the well. the oil tube is fi lled before running
A deeper pump setting the pump. The pump needs about
might be required. 10 drops per minute.
Page 12 ATTRA Maintaining Irrigation Pumps, Motors, and Engines

13. At season startup for water-lubricated Maintenance Tasks
turbine pumps: At season startup for oil-lubricated pumps:
Pre-lubricate line shaft bearings Start lubricating the shaft up to a
with light oil. week before starting the pump,
Periodically: or until the line shaft and column
are full of oil and the oil begins to
Adjust and maintain the pack-
run out at the top near the stretch
ing on water-lubricated, short-cou-
assembly. During this fi rst week,
pled turbines as directed for the
allow four to five drops of oil per
packing on a centrifugal pump.
minute. After starting, increase to
(See pages 10 to 11 above.)
10 to 15 drops of oil per minute.
Annually (or according to manufacturer’s Check the manufacturer’s instruc-
recommended interval) adjust the head tions to be sure of the requirement.
shaft nut on short-coupled turbine pumps: (Oil will drip slower at night when it
Remove the top motor cover and cools down.) The viscosity rating of
take out the set screw. the oil should be 9 or 10.
Remove, clean, oil, and replace the Periodically:
key stock. adjust and maintain the packing on
water-lubricated deep well turbines,
Loosen the head shaft adjusting nut
following the same procedures as for
(it has a left-hand thread) so the shaft
the packing on a centrifugal pump.
and bowls are resting on the bottom.
(See pages 10 to 11 above.)
Tighten the head shaft adjusting nut
two turns, which will raise the shaft
and bowl assembly enough to allow Submersible Pumps
A submersible pump is a turbine pump that is close-coupled to a submers-
for proper clearance. ible electric motor. Since both pump and motor are suspended in the water,
You should be able to turn the shaft the drive shaft and bearings required for a deep well turbine pump are elimi-
by hand once it’s raised. If you nated. The pump is located above the motor and water enters the pump
through a screen located between the pump and motor.
can’t, tighten the head shaft adjust-
Submersible pumps use enclosed impellers. The motors are smaller in diam-
ing nut one-half turn and try to turn eter and longer than turbine pump motors. Inadequate circulation of water
it by hand again. past the motor may cause it to overheat and burn out. The riser pipe must
Replace t he set screw a nd be of sufficient length to keep the bowl assembly and motor completely
submerged at all times and the well casing must be large for water to easily
motor cover. flow past the motor. Electrical wiring from the pump to the surface must be
watertight with sealed connections.
Caution: If you are unable to turn
the shaft by hand, and you have
raised the shaft by five or more turns Troubleshooting
of the nut, remove the pump, disas- This section identifies symptoms and pos-
semble, and inspect for damage or sible causes under Suction, System, and
debris. If you have any questions Pump. (See Troubleshooting Tables on the
about this procedure, consult your following page.) Find the Symptoms and
pump dealer. then look across to the left to see possible
causes. Most often, suction problems are
Deep Well Turbine Pump the cause. Contact your pump repair shop
for additional help.
Shaft adjustment needs to be more precise
for deep well turbines. Shaft stretch needs Caution: This troubleshooting guide
to be considered. Refer to the manufac- is general and does not cover all
turer’s instructions or consult a qualified the possible system configurations or
pump dealer. problems that might be encountered.
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