Century Centurion motor questions

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aggiejet

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Apr 27, 2012
51
tulsa, ok
Howdy,

I have a kidney shaped pool of approximately 25k gallons. I have a 1 HP AO Smith Century Centurion 230v motor with a Pentair Challenger pump. The filter is a Triton II TR-100 (sand filter) I only have one return line, that being the skimmer. The main drain line has a leak somewhere and is cappped off. We have run the pool this way for several years with no apparent cleaning problems. We run the motor during the pool season (here in NE OK, May-Sept)24/7 on the advice of our pool guy.

This is the eight season for us to operate the pool, and we are on our third motor. :grrrr: Is this typical? I was on the phone this week with a tech from Pentair talking about sand replacement for filter, and mentioned this to him. He said we should be getting five to eight years outta a motor. i checked the voltage at the motor and am getting 120 volts outta each wire at the back of the motor. Additionally, the the motor is hot to the touch. Is this normal? This motor is only about one month old. Replaced it late last summer, as I recall.

I have done quick forum search and didn't see much, so I posted new topic. I am new to the forum and this looks like a good place to get educated on pool ownership.

Thanks,
Mark
 
It is common for the motor to be quite warm.

I agree with the Pentair representative, motors should last longer than that. The fastest way to ruin a motor is to allow it to get wet inside. Sprinkler systems that spray directly on the motor are especially problematic. Leaks around the shaft seal can also rapidly lead to problems.

Some kind of roof or enclosure to protect the motor from sun and rain can help significantly, as long as it remains well ventilated.

By the by, running the pump 24/7 doesn't really help anything and tends to get expensive. However, it would not be related to the short motor lifetime, as those motors are designed to be run continuously.
 
What failed in the motor? Bearings, seal, windings, etc.

Also, do you happen to know what the original model# was for the pump? Challengers would be something like: CHII-NI-1F or CHII-NI-1A
 
I took the last motor to a local electrical shop. they said the armature and/or windings were burned up. FWIW, I swear that motor never sounded right even after intial installation. It was very loud, not like an electric motor should sound like at all.

I have the original pump. CFII-N1-1A are the model numbers. I just keep replacing the motor.

I am in the process of figuring out what the flow rate for this pump is and how many times my pool is getting turned over in a day, etc. My "pool guy" says the hardest thing on a motor is the start. I generally agree with that, and really don't mind running 24/7, but if it is not really necessary I thought it might add to motor longevity, but as Jason pointed out, it really shouldn't matter.

Thanks,
Mark
 
If there is something wrong with the wet end, it could be putting extra load on the motor which may be why the windings are burning up. If it happens again, you may just want to replace the entire pump.

As for motor starting, the motor will draw a little extra current on start but they are designed for tens of thousands of starts so that really shouldn't be an issue and is probably not the cause of failure. Plus you are wasting a ton of energy running the pump 24/7. The turnover for that pump should be around 7 hours but really, your run time should be set based upon how clean you want the pool.
 
I checked the wiring while I was checking the voltage. I couldn't read the guage on the insulation, but it appeared to be heavy gauge, in the 10/12 range. Certainly not 14.

so do people typically run their pump during the heat of the day during the summer months? do you guys typically "turnover" your pool once a day as a rough rule of thumb?

Thanks,
Mark
 
Sure do. As long as the pool is staying clean enough - there's no need to run it more than necessary. I run mine about 9-10 hours per day, and some people would say I'm running it "too much". I do have lots of trees around.

If I was you, I'd start with 8-10 hours and see what it looks like and adjust my runtime up or down, as you see fit. We do have our pumps on timers, but you should be able to pick one up for $50-$80 for one that will turn the pump on and off using a mechanical timer. You may even find them at your local Lowes / Home Depot type stores - be sure to get one that handles 240V dual pole - you can usually use ones that they show "for water heaters".

Edit - the "water heater" timers are not "rain tight", but the internals are identical. If you do get the water heater timer - try to put it out of the weather as much as possible. Mine is INSIDE a house type shed. If I wanted a timer out by my pump - then I'd want one in a rain tight box.

Examples of rain tight timers - http://www.a1poolparts.com/-strse-Timer ... gories.bok
Intermatic T104R3 and Intermatic T104P3 would be what you want for an outside timer on a 240V pump.
 

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swimcmp said:
Another thing to check is make sure your impeller is sized to the hp of the pump, this can cause the motor to overheat and cause premature failure.
Click to expand...

I look at the settup as having a motor (1 h.p.) and a pump. Two seperate items. The pump doesn't have a h.p. per se, does it? When I quiz my pool guy about the lack of longevity of my motors, he as well as a local pool supply store guy, brush this off as cheaper made parts and therefore not as high as quality as in the previous years.

When this pool was refurbished in 2004, the pool guy installed everything new. I don 't think the impeller has ever been changed. Is that what you are suggesting here, that somehow I have a wrong sized impeller after a changeout? I have seen these identical setups (ao smith motor w/ Challenger pump) sitting on display in showrooms as local pool supply stores. I assume the pool guy bought this same setup and installed it. That said, how do I check to make sure i have the "proper" impeller.

As an additional question, I am trying to figure out my flowrate. I have read the owners manual for the Challenger pump off of Pentair's website, but find nothing there that helps me determine my flow rate. Just trying to learn as much as I can about this pool stuff, as I am about to start 'Managing" my own pool.

Thnaks,
Mark
 
Mark, I wouldn't "assume" anything with the pool guy. It sounds like you may have picked up some interference the last motor change as you say the motor was making a different noise. Could be the impeller? From what I read the Wet End Is the original and never been changed? Mark will chime in soon with all flow rate info you'll ever want know about.
 
The CFII-N1-1A is a uprated pump so given the new motor is labeled 1 HP, even if it is an up rated motor it should be fine.

To double check, you could get a part# off of the impeller and we can make sure. Also, I will need the service factor of the new motor.

Also, for flow rate calcs, I need the following:

Diameter and number of individual suction pipes from the equipment to the pool
Filter PSI reading at the desired valve settings
Height of pump relative to the pool water level
Distance from the pool to the equipment
Pool/Spa Valve - yes or no
Check Valves - Number and locations
 
The SF on the side of the motor is 1.65

There is one 1.5 inch line that runs abut 45' from the skimmer to the pump.
PSI read at top of triton II filter is 6 psi
Pump is about 14" above water line
I have no Pool/spa valve and have no idea if there are any check valves anywhere

Next week I will take the motor off and try to get a measurement and part number off of the impeller.

Thanks,
Mark
 
If you do have a CFII-N1-1A impeller, then the flow rate should be around 66 GPM. But because the filter pressure is so low, it appears as though the suction side head loss is quite high and nearly the same as the return head loss.

Your new motor is a full rated motor and the pump is up rated so the motor is somewhat over sized for the pump but that should be ok. What is somewhat puzzling is that the motor is that hot since the impeller should be a lower load on the motor. When you take apart the pump, inspect all of the parts to make sure everything looks normal and nothing is damaged.
 
Thanks Mark. Just eyeballing it, I was guessing at least 50 gpm. Thanks for the gpm calculation. I tried to review the "Head pressure" info on the site here, but it got over my head pretty quick. (i blame it on the rural southern educational process)

It will be Thursday afternoon till I can get the pump apart. I'll keep you posted.

Thanks,
Mark
 
Howdy,
took the pump apart this afternoon. the number on the impeller is 35-5067. Oddly enough, that number does not match any of the impeller numbers in the owners manual that I downloaded from Pentair. Let me know what you think.
thanks,
Mark
 
That impeller is used on the high flow Challenger 1 HP uprated pump (CFII-N1-1a) shown here:

http://www.pentairpool.com/pool-owner/p ... ump-25.htm

Which is the pump you have so the motor would seem to be a correct match.

There might be something else going on in the wet end which is shortening the life of the motor so as I said before, if this happens again, I would seriously consider a new pump.
 
Mark,

I agree. I was looking at the wrong section of the manual. I see no visible problems with the pump. Looks pretty bacic and strikes me as something that either works or doesn't. Do you have any examples or symptoms i could look for that "might be something going on in the wet end."?

I was able to check the numbers on the wiring. I have 12 guage stranded wire running about 6 feet from the switch to the motor, so i am pretty confindent my wiring is adequate.

Thanks,
Mark
 
If you still have it apart, you could run the motor and watch the impeller spin to see if there is any wobble. Also, look at the inside of the diffuser to see if the impeller is rubbing against it. Other than that, the only other part that could cause extra load is the seal but I presume that was changed each time the motor was changed.
 

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