A.O. Smith Century Centurion Manual

A.O. Smith
531 North Fourth Street
Tipp City, OH 45371
937-667-2431 • Fax [phone]
www.aosmithmotors.com
Bulletin 2944
©A.O. Smith Corporation 2006 #2944 1/06

Installation
—
Maintenance
—
Service
—
Troubleshooting
CENTURY®
POOL & SPAMOTOR
MANUAL

1
Welcome to A.O. Smith’s line of Century®
Motors. This pocket manual is designed for
one purpose — to make it simple for you to
install, maintain and troubleshoot Century pool and
spa motors. Contrary to what you may be thinking just
now, your last name doesn’t have to be Edison in order to
properly service the motors shown in the following pages.
All you need are a few basic tools and some helpful hints;
the kind that appear throughout this
booklet.
We’ve included all the information we think you’ll
need to repair the most common pump motor problems
encountered out in the field. This easy to read manual con-
tains great illustrations and diagrams for quick
reference. Assisting your customers is your job. Helping
you do that with minimum delay is our job; that’s why
we’ve prepared this informative manual.
INTRODUCTION

2
Replacements for every brand. Every now and then
you probably come across a motor that’s beyond repair.
When you do, remember that A.O. Smith manufactures
replacement pool and spa motors for practically every
brand you’ll ever encounter in the field. So save yourself
some time and effort and just ask for Century first — at
any A.O. Smith distributor or dealer. Century motors are as
rugged as any you’ll find, but keep in mind that all motors
need service and maintenance at one time or another.
Safety first. Remember, before you begin to work on
any electrical appliance be sure to TURN OFF THE
POWER. The only time you’ll need the power on is
when you check motor voltage and amperage. If you over-
look this important guideline, someday you could unex-
pectedly get a real charge out of your work! Always play it
safe — double-check to be certain that the power is off
before you start to work on a pool or spa motor.
If you have any suggestions or would like more
information about a particular subject, please write
or call:
A.O. Smith
531 North Fourth Street
Tipp City, OH 45371
800-543-9450
www.aosmithmotors.com

3
Century Pump Motors ......................................................5
Design Features................................................................7
Nameplate Information....................................................9
Installation
Heat..........................................................................13
Moisture...................................................................14
Power Source ..........................................................14
Altitude.....................................................................14
Mounting..................................................................14
Electrical Connections .............................................15
Grounding................................................................15
Wire Size..................................................................15
Wire Selection Guide.....................................................16
Tools ................................................................................17
Maintenance
Moisture...................................................................17
Cooling.....................................................................18
Seasonal...................................................................18
Cleaning ...................................................................18
Lubrication...............................................................18
TABLE OF CONTENTS

4
Motor Troubleshooting
Motor Fails To Start (makes no sound)..................19
Motor Fails To Start (hums, tries to start,
blows fuse or trips breaker)....................................20
Motor Starts But Shuts Down
(overload problem)..................................................21
Noisy Motor.....................................................................21
Motor Hot, Smoking Or Cycling.....................................22
Information Needed For Motor Replacement ..............23
Troubleshooting A Capacitor .........................................23
Best Way To Use A Volt-Ammeter.................................24
How To Replace Bearings..............................................24
Service ............................................................................27
Wiring Diagrams’ Table of Contents.............................28
Wiring Diagrams.......................................................29-54
Date of Manufacture Table ............................................55

5
Centurion®, C-flange
Switchless “1081” Motor
• Standard Efficiency
• E-Plus, High Efficiency
• 1⁄2– 5 Hp
• No Switch, No Governor
• Single phase or three phase
• Suitable for operation at 50 Hz,
1.0 service factor
• Aluminum or cast iron NEMA “C” mounting brackets
• True NEMA 56-frame
• Keyed or threaded shaft
• UL standard “1081” approvable
• Full-rated and Up-rated
• 50° C Ambient
• Available as a Century two-speed motor
Centurion®SE, C-flange
Switchless “1081” Motor
• 1⁄2– 5 Hp
• Standard Efficiency
• Single phase
• Aluminum NEMA “C”
mounting brackets
• 50° C Ambient
• True NEMA 56-frame
• Keyed or threaded shaft
• UL Standard “1081” approvable
• Full-rated and Up-rated
• 303 stainless steel shaft
CENTURY® CENTURION &

6
Centurion®, Square Flange
Switchless “1081” Motor
• Standard Efficiency
• E-Plus, High Efficiency
• 1⁄2– 5 Hp
• No Switch, No Governor
• 303 stainless steel
threaded shaft
• Suitable for operation
at 50 Hz, 1.0 service factor
• Single or three phase
• True NEMA 56-frame
• UL standard “1081” approvable
• Full-rated and Up-rated
• 50° C Ambient
• Available as a
Century two-speed motor
Neptune®, C & Square Flange
• Standard Efficiency
• High Efficiency
• 1⁄2– 3 Hp
•Advanced Switch Technology
• 48 frame shell diameter
• 303 stainless steel threaded shaft
• UL standard “1081” approvable
• Full-rated and Up-rated
• 50° C Ambient
E-PLUS®MOTORS

7
Flex-48™ Single-Speed Motors, Thru-Bolt Mount
Suitable for jetted tubs and above-ground pools and spas.
• 1⁄2- 3 Hp
• 56-frame conversion base
• 3-1⁄2” shaft height
• 3⁄8” threaded shaft
• Auto-reset overload
protection
• 1.0 service factor
Flex-48™ Two-Speed Low Amp Start & Run Motors
For Spas and above-ground pools, thru-bolt mount.
• 3⁄4- 3 Hp
• 56-frame conversion base
• 3-1⁄2” shaft height
• 3⁄8” threaded shaft
• Auto-reset overload
protection
• 1.0 service factor
C
entury pool and spa pump motors are tailored for
demanding pool loads and environments. Check these
outstanding features:
1. Full-rated 56-Frame diameter gives greater thermal
capacity, better durability with industrial quality construction.
CENTURION®
DESIGN FEATURES
FLEX-48™
POOL AND SPA MOTORS

8
2. All Threaded shafts are 303 stainless steel for superior
corrosion resistance. Keyed shaft of carbon steel is iron
phosphate treated to prevent rust. Stainless steel shafts
provided on cast iron C-flange, keyed shaft product.
3. Double-sealed high thrust bearings protect against dirt and
moisture. Factory lubricated, never need regreasing.
4. Special aluminum alloy brackets or cast iron NEMA “C”
brackets resist corrosion from pool chemicals.
5. Drive-end bearing locked to limit shaft endplay.
6. Continuous rated run capacitor provides high running
efficiency and better starting performance in low voltage
situations.
7. Easy connect terminal board is designed with screw post
line terminals. All you need is a screwdriver for fast and
easy installation wiring.
8. Moisture resistant, Class B insulated windings for extra
protection against moisture, high ambient temperatures,
salt spray, chemicals, diatomaceous earth, sand, dirt,
insects, etc.
9. Motors designed to meet UL Standard #1081, protects
internal components from rain, dirt and chemicals.
10. Class B automatic reset overload protector suitable for
high ambient temperatures. Prevents nuisance tripping in
hot areas.
CENTURION®
DESIGN FEATURES

When you need information about the motor
you’re servicing, you’ll always be able to find it
printed on the motor nameplate. On A.O. Smith
motors the nameplate is usually found on the side of the
motor, below the capacitor. Shown below is a sample
pool motor identification nameplate. As you read the
nameplate, refer to the guide so that you understand
the meaning of each item that the manufacturer
provides about its motor. Remember also that your
dealer or distributor can give you valuable information
that can help you to make the correct selection of a
replacement motor.
9
NAMEPLATE INFORMATION

1. CAT NO (Catalog Number): This number indicates
that the motor is a stock rating, readily available
from standard inventory as a replacement pool
motor.
2. PART: This identifies the motor’s specific design
by part number.
3. FR (Frame): The frame identifies the mounting
and shaft configuration. It doesn’t indicate the
diameter of the shell. A.O. Smith’s line of Centurion
and Centurion SE motors have a “56 frame” shell
and are 6.5 inches in diameter. Neptune and
Flex-48 products are designed in a 48 frame shell
and are 5.6 inches in diameter. Common terms you’ll
see on the nameplate are “56J,” “56C” and “56Y.”
The 56J is always a C-flange, threaded-shaft motor;
the 56C is always a C-flange, keyed-shaft motor.
Motor-frame mountings with the “Y” identification
10

identify motors not specified by NEMA mounting
and shaft standards.
4. TYPE: The electrical design of the motor is shown
by its type. A.O. Smith uses “CX” to identify its
switchless design. Other codes include “CS” for
capacitor-start, “S P” for split-phase and “CP” for
capacitor start / capacitor run. Be sure to check with
the dealer or distributor, because motor type codes
may vary among manufacturers.
5. HP (Horsepower): Conventional unit of measure-
ment for power. One horsepower equals 746 watts.
6. RPM (Revolutions Per Minute): RPM states the
rotational speed of the shaft at rated load.
7. HZ (Hertz): Measurement of frequency, equaling
cycles per second of alternating current.
8. PH (Phase): Denotes a single- or three-phase
motor.
9. SF (Service Factor): Service factor is the measure
of the reserve margin built into a motor. Motors
rated over 1.0 SF allow the motor to operate at a
higher margin than designated by the horsepower
rating. Maximum horsepower capability equals
horsepower multiplied by the SF.
(continuous operation).
10. VOLTS: Voltage is the required electrical potential
applied to the motor, the force that produces current
in an electrical conductor.
11. AMPS: Electrical current flowing through the
conductors. On pool motors, the amperage is
maximum or service factor amps that result at
11
NAMEPLATE INFORMATION

maximum horsepower (Hp x SF).
12. TIME: Time indicates the duty cycle of the motor.
Pool and spa motors are generally rated for
continuous duty.
13. AMB (Ambient Temperature): The maximum
ambient (surrounding) temperature in which the
motor is designed to operate. This temperature
is shown in Celsius rather than Fahrenheit.
14. INSUL CLASS (Insulation Classification):
The temperature rating of insulation used in the
construction of the motor. Most pool and spa
motors use a Class “B” insulation.
15. ENCL (Enclosure): Common enclosures used
include DP (dripproof) and TEFC (totally enclosed
fan cooled). Most pool and spa motors feature a
dripproof design, with “1081” features.
16. CODE: The NEMA code letter specifies locked
rotor kVA per Hp (volts multiplied by locked rotor
amps, divided by 1000 times rated HP).
17. SERIAL: The serial indicates the date of
manufacture, which often appears as year/month
combinations. Serial code information for each
pool and spa motor can be found in guides and
bulletins provided by the manufacturer (See p.55).
18. VOLTAGE DIAGRAM: This diagram provides
information on the correct electrical connections
to ensure proper operation of the motor.
19. WARNING: The warning at the bottom of the label
re-emphasizes that voltage can be hazardous.
Always TURN THE POWER OFF before working on
a pool or spa motor.
12

The number one enemy of a motor is
heat. Overheating always results
whenever there is a lack of clean, continually-circulating
air for a motor. Heat can damage a motor’s windings,
insulation, bearing lubricant and run capacitor. In short,
heat can quickly decrease the service life of a motor.
Remember, proper ventilation is always a crucial consid-
eration when installing a motor.
If at all possible, install a motor in a location that is
free of dirt, dust or airborne debris, such as leaves.
Indoors is best, but not in areas with high humidity,
such as a laundry room or shower area. If the motor is
installed outdoors, try to choose a shady spot that’s pro-
tected from leaves and grass clippings. If you cover the
motor to protect it from possible debris or water, be
sure to leave enough space between the cover and the
motor for adequate ventilation.
A.O. Smith single phase pool and spa motors
feature a thermal overload protector that will shut down
the motor if it overheats. As the windings begin to cool
down, the overload protector will automatically re-start
the motor. Blocked ventilation or an overload condition
can cause the motor to shutdown on a repeated basis.
If a problem cannot be located or if tripping continues
after a noted problem is corrected, contact the original
equipment contractor for a recommendation on
matching motor horsepower to the pump.
TIP: In situations where the ambient temperature is
exceptionally hot, utilizing an E-Plus (High Efficiency)
motor in place of a standard efficient motor can
prevent the overload protector from nuisance tripping.
13
HEAT
INSTALLATION

Century and Neptune
motors have superior
resistance to moisture, but you should avoid placing
the motor where it can be splashed. Avoid installing the
motor in low spots where it could collect water and be
flooded. In fact, it’s probably a good idea to elevate the
motor at least two inches off the ground.
Before you turn
the motor on,
check to see that the line voltage, phase and frequency
match the specifications shown on the motor name-
plate. Current capacity must be adequate enough to
maintain rated voltage at the motor terminals under
all conditions. If it’s too high, contact the local utility.
If it’s too low check for overloaded circuits, loose
connections or wire of the wrong gauge (see wire
selection guide).
Generally, motors will
run hotter with increasing
altitudes. For installations more than 3,300 feet above sea
level, it’s advisable to use a motor with the next
larger horsepower rating than the one recommended
for that application at sea level or use a A.O. Smith E-Plus
(High Efficiency) motor of the same rating when available.
Fastening the pump and
motor assembly securely
to a foundation or base will prevent vibration, loosening,
and future misalignment. Make sure that the motor and
pump assembly rotate freely before starting the motor.
14
MOISTURE
POWER SOURCE
ALTITUDE
MOUNTING

The task of wiring
your motor is fairly
simple. The wiring
diagrams shown on the following pages are color-coded
for easy reading. The appropriate part number is listed
in each illustration, just in case you need to order the
complete wiring diagram or connection label sticker
for your motor. Make sure the connections are tight
to prevent failure or overheating. If you do find loose
connections, check for excessive vibration.
Without proper grounding
of a motor, serious elec-
tric shock is possible. A grounding conductor should
always be connected under the green grounding screw,
which is located within the terminal compartment of the
motor. National and local electrical codes are important,
and should be adhered to when working
on a motor.
Incorrect voltage at the
motor terminals can cause
the motor to overheat. It’s a good idea to check the
electrical supply wires to confirm that they are sufficient
to handle the motor load. For example, if you’re using
a 1-1⁄2Hp motor at 115 volts over a distance of 150 feet,
use #8 wire. If the motor can be installed to
operate on 230 volts, #12 wire should be sufficient
for a 150 foot distance.
15
GROUNDING
WIRE SIZE
ELECTRICAL
CONNECTIONS

16
115V Power Line
Maximum Distance from Fuse Box to Motor
Motor Hp 50’ 100’ 150’ 200’
1⁄314 14 12 12
1⁄214 12 10 10
3⁄412 12 10 8
1 12 10 8 8
1-1⁄210 10 8 6
210 866
3 ————
230V Power Line
Maximum Distance from Fuse Box to Motor
Motor Hp 50’ 100’ 150’ 200’
1⁄314 14 14 14
1⁄214 14 14 14
3⁄414 14 14 14
1 14 14 14 12
1-1⁄214 14 12 12
2 14 14 12 10
3 12 12 10 10
THE SIZES SHOWN IN THE FOLLOWING WIRE SELECTION
CHARTS ARE RECOMMENDATIONS ONLY. ALWAYS FOLLOW
LOCAL AND NATIONAL ELECTRIC CODES.
Guides for copper conductors only.
WIRE SELECTION GUIDE

17
With a few simple tools, you’ll be ready for just
about any kind of basic motor service. To make
your job easier when installing or servicing a
pool or spa motor, make sure that you have these tools
in your toolbox before you begin working...
• Standard screwdriver
• Wide blade screwdriver
• 1⁄2” open end wrench
• Rubber mallet
• Clamp-on ammeter/voltmeter
• Ammeter
• 5⁄16” nut driver
• Needle-nose pliers
• Tape for marking
A.O. Smith pool and spa pump motors are built
tough, to run day after day without being serviced.
When service is necessary, serviceable parts usu-
ally can be accessed quite easily. For example, capaci-
tors are externally mounted, and single-phase motors
have screw-type connectors for quick reconnection in
the field.
Water leaks from pump
seals or pipe joints should
be repaired to prevent failure of bearings and insulation.
DO NOT splash or spray the motor. Mount the motor
away from low spots and damp areas, and take mea-
sures to protect it from windblown rain.
MOISTURE
MAINTENANCE
TOOLS

18
An operating motor is usually
too hot to touch by hand.
It should be located away from direct sunlight and other
heat sources, such as laundry appliances and water
heaters. Provide for ample air circulation around the
motor. Clean the air inlets as required, making sure that
the POWER IS OFF first.
Whenever the motor must
be shut down for extended
periods, be sure all surfaces, vents and interiors are dry
to prevent rust. If the motor is kept outdoors, cover it
to prevent debris such as blowing leaves, dirt and snow
from clogging the inlets. DO NOT SEAL THE MOTOR
IN PLASTIC OR OTHER AIR-TIGHT WRAPPINGS,
because condensation may form on the inside,
damaging bearings and insulation.
In general, the inside of
the motor should not need
cleaning if proper safeguards are made against contami-
nation by dirt, lint or sand. If you want to clean the
outside, simply use a damp cloth. Don’t spray the motor
with a water hose. If it’s accidentally flooded, have it
inspected at a A.O. Smith authorized service center.
The ball bearings
in A.O. Smith
motors are double sealed, permanently lubricated. If it
appears the bearings have failed, simply replace them.
COOLING
SEASONAL
CLEANING
LUBRICATION
MAINTENANCE