By Century Motors



Part # B859

Warranty 1 Year

Manufacturer Code B2859

Dimensions 14" L x 8" W x 6.5" D

Alternate Part #'s 0-193987-24, 10-177476-20, 16-177476-28, 177217, 177476, 18254, 186019, 187334, 193987, 196240, 196251, 355024S, 5KCR39UN6190X, 5KCR48UN2108AX, 7-177217-25, 7-177476-20, 7-177476-26, 7-177476-28, 7-193987-24, 7-F56AA13A04-25, 7-F56AA41A01-24, 8-177476-20, 90106949, 90106949r000, B2859, C1247, EB859, EUSQ1202, O-193987-24, P719, SP3215Z1M, SPX3215Z1MR, V18254, AOSB2859, MGT-60-2859

Product Description


Century B2859 Details:

A.O. Smith Centurion replacement motor for pool pumps. Specifications: Voltage = 230/115 Max Amps 11.2/22.4, Single Speed, Switchless, RPM = 3450, Threaded Shaft, Frame = 56Y, Service Factor = 1.10. Used on the following models: Sta-Rite: Max-E-Glas, Max-E-Glas II, Dura-Glas, Dura-Glas II, Dyna-Glas, Dyna-Max. Pentair: Whisperflo, Challenger, Pinnacle and Anthony AR2 Series.

Commonly Used On

  • Jandy PlusHP PHPM2.0
  • Pentair Whisperflo WF-28

Note: NOT California Title 20 Compliant. 

California Title 20 Compliant Option:

Motor Image Motor Image

Product Specifications

2.0 HP
230/115 V
10.5/21.0 amp
Service Factor:
Total HP:
2.2 HP
Century (A.O. Smith)
3450 RPM
Commonly Used On:
Sta-Rite: Max-E-Glas, Max-E-Glas II, Dura-Glas, Dura-Glas II, Dyna-Glas, Dyna-Max. Pentair: Whisperflo, Challenger, Pinnacle and Anthony AR2 Series
Whisperflo & Challenger
Pump Model:
WF-28 & CFII-N1-2A

?     Asked on 1/11/2012by Guest

What is Service Factor?

A  Answered on 1/11/2012 by InyoPools Product Specialist Patrick P.

Service Factor(SF) is a multiplier that when multiplied by the horsepower of the motor indicates the total permissible horsepower loading that may be carried when the motor is operating at rated voltage and frequency. The most important thing to remember when replacing a motor is that the replacement motor's horsepower times its service factor must be equal to or greater than the original motor's horsepower times its service factor. The Service Factor rating can be found on the motor label. See Step 4 of our How to Read a Pool Motor Label guide.

?     Asked on 1/12/2012by Guest

Why do I need to purchase a new shaft seal?

A  Answered on 1/12/2012 by InyoPools Product Specialist Patrick P.

We strongly recommend replacing the shaft seal. The purpose of a shaft seal is to prevent water from running down the shaft of the motor and into the motor housing. Water will damage the bearings and cause the motor to fail. A new shaft seal should be installed whenever a motor is replaced. The motor manufacturer can deny the warranty if the motor fails to due to water damage from a faulty shaft seal. To find your shaft seal you will need to visit our Pool Pump Parts Page or the Spa Pump Parts Page and select your make and model.

?     Asked on 1/12/2012by Guest

Why should I purchase a Tune Up Kit?

A  Answered on 1/12/2012 by InyoPools Product Specialist Patrick P.

A Tune Up Kit includes all of the essential replacement seals and gaskets for the pump. The seals and gaskets should be replaced when installing a new motor on your pump. New seals will prevent the pump from leaking water or losing the prime. A Tune Up Kit will protect your motor and ensure that the pump is working efficiently.

?     Asked on 4/18/2015by Kim

What tune-up kit do I use with this motor?

A  Answered on 4/19/2015 by InyoPools Product Specialist Alex V.

Kim, The tune up kit is based on the pump housing model not the motor. If you can get us the pump model, we can help you find the correct kit

?     Asked on 4/21/2015by JR Dobson

Do you have a replacement form1.5 hp part 7 177476 20? 1081 pool pump duty mount horizontal. What If so what else would I need and how $$? JR Dobson

A  Answered on 4/22/2015 by InyoPools Product Specialist Robert M.

Hello JR - The replacement motor is model B858. The cost is $264.99.


Est. Repair Time

1 to 2 hrs

Tools Needed

Screwdriver, Socket Set

1     0

Pump broken - Saved $1000 by just replacing the motor

Written on 8/27/2022 by Guest

The morning after a bad thunderstorm we noticed the pool was not running, so I figured the fuse went and left it. After three days (and wanting to use the pool the following weekend) I went to investigate. The motor was brumming and was extremely hot…..
First thought was change the capacitor, so ordered one on Amazon….. at the same time I figured I should do something about the pump as it is nearly 10years old and runs 365 days a year.
Our pump is bolted to the ground and the back of the motor is around 1.5” - 2” from the fence, so while looking at the pump I couldn’t see if it was connected 115v or 230v (and was too lazy to measure) so I figured I would order a dual voltage pump to replace it,
Prices for a new 2hp Pentair Whisper flow dual voltage are between $1200-$1900 ($1900 was for an exact replacement). ……then i found the Inyopools website for motors.
I went through the website, found the motor I need. That linked to a video on how to replace the motor on my pump and I decided to order it. The video was clear and showed a step by step guide.
The capacitor I ordered from Amazon came the next day… I replaced it and got the old motor to run, but it was rough and extremely loud, but at least I was able to filter the water.
Three days later the motor arrived. Due to the space constraint I was not sure I would be able to do it without unbolting the whole unit and detaching the piping, but I gave it a go. with a little bit of wiggling I was able to get the old motor out.
Following the steps on the video I transferred over the parts from the old pump. I bought a tune up kit from Inyo, as they advised and replaced the shaft seal O-rings etc too.
As i knew I would have to wiggle the motor back in, I decided to superglue a few dots on the rubber seal to hold it in place (don’t know whether this was ok, but the glue said for rubber).
Anyway it took me a few minutes to wire it up due to a short cable and then about 10 minutes to get it back in. Tightened It up, turned it on and it worked. Much much quieter than my old motor.
If I had to give one tip, it would be to use a socket set for the wiring. It was a lot easier taken the wiring off the old motor than with a screwdriver.
Thanks Inyo. If I had not have seen the video, I might not have bought the motor. Needless to say, I am extremely happy I was able to do it myself and save $1000.

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Est. Repair Time

1 to 2 hrs

Tools Needed

Screwdriver, Nut Drivers, Pliers, Wrench Set

1     2

Old pool pump not functioning

Written on 5/2/2021 by Guest

Bought a century 2.0 HP pool pump. My husband turn off the breakers. Old pool pump was removed. New pool pump was installed. Breakers were turn back on. The installation was easy.

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Est. Repair Time

More than 8 hrs

Tools Needed

Screwdriver, Nut Drivers, Pliers, Socket Set, Wrench Set, Adjustable Wrench

0     2

No problem

Written on 10/4/2019 by Guest

No problem

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Review Summary

 (Average 4.9  out of 5 stars)
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