Pump motor is starting to go, just replace motor or need a different impeller in wet end?

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steveg_nh

steveg_nh

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Oct 7, 2013
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Southern NH
Hi all, could you some help on making sure I do the right thing. After 11 seasons, the AO Smith motor on my Hayward inground pool pump started to not sound so good. Water is pumping just fine, but sounds like the bearings are starting to go, so I'm thinking just a replacement motor. I reached out to the pool company that put it in, and closes the pool every year, and he said if I can still get the motor, just do that, as anything over 1HP has to be a variable speed setup now. I told him the plate says it's 3/4hp, and I told him I could get the same rated motor. He mentioned that I would want to get it with a new impeller for that size motor. That the original motor came in a max rate and a full rate true horsepower, that was over 1HP.

But from what I'm seeing online, with the exception of the SF rating (1.65 vs 1.85 on the old one) and the enclosure type (DP vs ODP on the old one), everything else is the same. So what's the story, can anyone help solve it? I don't want to keep asking the contractor as he knows I'll do it myself, so figured I'd see if some folks here have some insights. Here's a pic of the current dying motor (and video) and a link to what looks like a drop in replacement, or very close. I haven't looked too much yet to see if I can find the exact motor, but this popped up when I put in the part number.

Century (A.O. Smith) .75 HP Full Rate Motor, Square Flange 56Y Frame, Single Speed - Model B847 - INYOPools.com

Century 3/4 HP Square Flange 56Y Full Rate Motor - B2847V1
www.inyopools.com www.inyopools.com

Running Pump Clip

Thanks.
 

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I went through motor replacement recently on my TriStar, so this is fresh on my mind. Your old pump total HP (THP) is 1.39, while the one you're looking at is THP 1.24. The contractor is saying you'd need a smaller impeller to match the lower power motor, but I doubt it's a big enough difference. In my case, I replaced my single-speed 1 THP motor with a variable speed 1.3 THP (Century V-Green EVO). I also changed my impeller to a larger version at the same time. The VS motor was more costly than a single speed like you're looking at, but I'm running 24x7 at very low RPM. The electricity savings will quickly cover the extra pump cost, to say nothing of the joy of super-quiet operation. Lots of information in the archives here if you want to consider that route. Consensus is to go with a larger motor (and impeller) and run at very low RPM.
 
Thank you. I'm looking for the simplest solution, and while I'm very handy, impeller sizing and THP and all that isn't something I'm that similar with. Can I ask where on the nameplate you saw the THP of 1.39, or did you have to look it up?

I run my pump about 9 hrs a day, and it's been a bulletproof pool, so if I can just swap the motor, great. Not sure how hard it is to swap the impeller. Maybe it's obvious once the motor is removed, I'll have to see if I can find a video on YouTube. But if I can, I'll try to find a matching spec motor of 1.39 THP.
 
Talked to Inyo pools today, they were very helpful. They recommended a pump that is slightly larger in THP, and said I don't need to replace the impeller, but I could if I wanted to pick up a few more gallons per minute. They said it wouldn't hurt the larger motor to use the same impeller though. For $73 for another impeller, not sure it's worth it, as I would have the same water flow. If I understand it right, you would hurt a motor if the motor was smaller, trying to spin an impeller too large, but the other way around is ok when it's close. Is that right? This is what was recommended, appreciate if anyone has any thoughts:

Motor: Century (A.O. Smith) 1.0 HP Full Rate Motor, Square Flange 56Y Frame, Single Speed - Model B2848 - INYOPools.com
Seal Kit for TriStar pump: Hayward TriStar, EcoStar Pool Pump Saltwater Seal Kit By | By Pureline | GOKIT80SALT - INYOPools.com
Slightly larger impeller, if desired: Hayward Tristar Impeller with Screw, 1.5THP - SPX3210C - INYOPools.com

Thanks
 
I don't know why you wouldn't get a century or nidec variable speed motor, impeller and seal kit. Might be twice the price, but it would payback in a short period of time with reduced electricity costs.

What is the model # of the pump (not the motor)?
 
I was just looking at this new motor, and the amperage is significantly higher, so made me question this decision actually. The pump is a TriStar SP3207EE. Do you not have to change out the main body, thereby getting into the plumbing? If not, I may do this, and I assume I have to reprogram my AquaLogic system to know it's a VS motor.
 
Thanks for the help. I see two motors on that parts page, but there are others? How do I know which pump to pick? Looking at those VS motors on that page, they come with the matched impeller already. I'm at about $450 if I do the new single speed, impeller and seal kit already. The amperage draw of these VS motors is more than the single speed I have now, but I assume that's only when they are running at VS? My pool installer says he doesn't run them variable and just sets them to one speed. Wonder why he would do that.
 
steveg_nh said:
The amperage draw of these VS motors is more than the single speed I have now, but I assume that's only when they are running at VS? My pool installer says he doesn't run them variable and just sets them to one speed. Wonder why he would do that.
Click to expand...
You will spend less money on electricity...by a lot.
I run mine at 1400 RPM, 24/7, and it costs me less that $20/month.
I run at 2200 when I use the heater, it requires higher flow.

Here are the reasons to run your pump. Link-->Why you run your pump...

Cost comparison.
Pump Cost.png
 
WOW! :) That is a lot. Geez. Any tips on how to select the right VS pump then? Seems like a no brainer honestly. My pool company quoted $1500 for a VS motor to fit my pump, plus installation. I'm more than capable of the install, and the owner knows it which is why he pointed me to look into a few things.
 

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Will it interface with my AquaLogic system as a VS pump, so for things like when the heat pump is on, or the booster pump, it can automatically speed up? I can research it if you aren't sure (you've been super helpful already). I have to make sure I maintain the 56Y frame setup for the pump too, I believe. Need to understand that vs the 48Y showing on the EVQ225.
 
The "Y" part of the frame is the important part. That means square flange and the bolt pattern is the same for both. 48 vs 56 is just a diameter difference of the motor casing. I replaced my original 56Y with a 48Y V-Green EVO and it came with a little rubber spacer to take up the room on the original support bracket.
 
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