New pump feels hot

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Rocketfish

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Bronze Supporter
Jun 6, 2016
102
Orange County, CA
My home warranty covered repairs to my pool equipment so they came out and repaired my non operating heater. In addition to that, they replaced the pump motor since it seemed to seize up THE DAY BEFORE the guy was to inspect the heater. To my surprise, the repair guy replaced the motor with a brand new black and shiny motor.

Now, it seems to run awesome, and in fact, there don't seem to be any more bubbles coming out of the return jets. I believe the new motor, with new flange to the filter got rid of the previous leak problem I had.

Anyhow, I ran the new pump for about four hours last night for the first time and the motor felt hot to the touch. I read somewhere here that if you can touch the motor for 8 seconds, then that is completely normal. Is this true? I want to make sure everything is installed correctly. I never did feel the old motor so have nothing to compare it to.
 
The motor should shut off on it's own if it is getting too hot. But I can check if the correct motor was installed. Sometimes they use the incorrect motor replacement.

What is the make/model # of your current pump (A.O. Smith is the motor not the pump)?

Can you post a picture of the new motor label?
 
Rocketfish said:
My home warranty covered repairs to my pool equipment so they came out and repaired my non operating heater. In addition to that, they replaced the pump motor since it seemed to seize up THE DAY BEFORE the guy was to inspect the heater. To my surprise, the repair guy replaced the motor with a brand new black and shiny motor.

Now, it seems to run awesome, and in fact, there don't seem to be any more bubbles coming out of the return jets. I believe the new motor, with new flange to the filter got rid of the previous leak problem I had.

Anyhow, I ran the new pump for about four hours last night for the first time and the motor felt hot to the touch. I read somewhere here that if you can touch the motor for 8 seconds, then that is completely normal. Is this true? I want to make sure everything is installed correctly. I never did feel the old motor so have nothing to compare it to.
Click to expand...

That is correct...as a common rule of thumb, if you can hold your hand on the pump for 8 seconds then it is fine. As a previous poster stated in another thread, 'your pump is supposed to be hot, but not hot enough that you can cook eggs on it'....
 
Hey guys. I will take a picture of the new pump when I get a chance. I tried touching the motor last night after letting it run for 4 hours. I could NOT hold my hand on it for more than even 2 seconds! This thing is definitely running hotter than it should, I believe. It even "sounds" weird to me. The pool guy left the old flange, and presumably the old impeller and some other tell tale parts of his installation. I'll get that info to you guys as soon as I can.

This new motor has a noticeably smaller diameter than the previous one, I can tell you that for sure.
 
He may not have properly matched the new impeller with the new motor. Unfortunately, more common then it should be.
 
This is the new setup along with what the technician left. The black motor is the new part.


Closeup of the new motor


Closeup of what I perceive as the pump
IMG_0299.jpg

I do NOT have any pictures of the previous motor, as he disposed of it. Perhaps I should check my trash? All I remember is that it was definitely bigger in diameter than this black one. you can see a small white support piece of wood underneath in fact.

The good things is that I now believe that the system is entirely sealed, because previously, the pump had to prime itself and you could see the pump filter basket fill up with water each time I turned it on. That pump basket is airtight now as is evident through the see through cap.

It is still definitely very hot after running for a couple of hours, what can be the problem here?
 
I am not seeing the attachment for the new motor. Post the label HP and the service factor of the new motor.
 
The motor is the correct size for the pump. But it is a large motor/pump and it may not be an efficient motor so it could generate a lot of heat even though it is running properly. As I said before, if the motor gets too hot, it should shut down on it's own and then you know you have a problem.
 
Service factor should not be an issue here. The motor is rated as 2hp, the pump is 1.5 rated. The unused energy is not being used to spin the impeller, it is being wasted as heat.
 

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Service factor always matters. The pump has a THP of 1.5 * 1.47 = 2.2 and runs close to that. The new motor has a THP of 2 * 1.2 = 2.4 so their ratings are actually pretty close. The label HP of a motor is pretty much meaningless without the service factor.
 
Maybe it’s just a cheap motor. The label says “Motors Unlimited LV”. Can’t find any information about who that is. Maybe it’s a rebuilt motor.

I would suggest that you check the volts and amps at the motor under load. I would also suggest checking the temperature of the motor surface. You can get a cheap Non-Contact Infrared Thermometer with Laser Targeting at various places. Also, check that the impeller turns freely.

That’s a really old pump. I would have replaced the whole thing. The seal plate was bad and was replaced. I suspect that the impeller was also bad and was likely replaced. They might have installed the wrong impeller.
 
The method used here to determine if the temperatures is the right one is not an accurate one. The clue to determine this is on the motor's label . the motor s a insulation class B. -Without getting too technical- that means that the motor can run at a temperature of 266 degrees Fahrenheit (yes you could cook an egg on that motor, lol).



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tmobileguy said:
That is correct...as a common rule of thumb, if you can hold your hand on the pump for 8 seconds then it is fine. As a previous poster stated in another thread, 'your pump is supposed to be hot, but not hot enough that you can cook eggs on it'....
Click to expand...
The method used here to determine if the temperatures is the right one is not an accurate one. The clue to determine this is on the motor's label . the motor s a insulation class B. -Without getting too technical- that means that the motor can run at a temperature of 266 degrees Fahrenheit (yes you could cook an egg on that motor, lol).



Sent from my 6039A using Tapatalk
 
Class B insulation has a maximum rating of 266F but no competent engineer would ever design the motor to normally operate at that temperature. Ratings and operating points are two completely different things.
 
There’s a big difference between the Maximum Operation Temperature Allowed and what temperature a motor should run at.

Also, the frame is labeled as a 56, but It looks like a 48 frame. If they got the frame wrong, maybe they got the hp wrong, too.

And the bond wire is incorrect. The wire is a stranded insulated wire when it should be a solid bare wire. The wire is not even making contact with the metal of the bonding lug. The insulation is still on the wire in the lug. It might not even be a bond wire. It looks like just some random wire stuck in the lug.

I’ll bet if you scratch a little bit of the black paint off, you will see that the pump was repainted.
 
whoa guys... thanks for all this info. Before I read your comments this morning, I asked the home warranty to bring back a pool technician to inspect the motor. I told them it was running really hot after an hour or two of work. Hopefully they are smart enough to verify stuff you all mentioned. I'm really concerned about the bonding now. I will keep you all posted.
 
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