Pump Motor Cycling

JoeFletch

Active member
Nov 7, 2014
43
Bradenton, FL
I was in my house earlier today and noticed that my pump was off a little earlier than normal. Went out to check on the pool chemistry and the pump was running. Turned off while I was out there. I didn't notice a hum while I was out there like the motor was trying to start. After a minute or 2 it started again, then off again in another minute or 2. Turned it off and got my electrical equipment.

Turned the pump back on and got the following readings.
  • 230V at the motor, which is expected.
  • 11.29 amps on one leg.
Motor appears to be rated for 9 amps. From some internets reading, the max delta should be 10% (roughly 10 amps). So I am over by a little over 1 amp.

This motor is just about 2.5 years old. Does this mean that the end of life for this motor is near? Anything else I should check?

Water flow appears to be proper. I clean the filter weekly (typically on the weekends). So I do not expect any obstruction but I am going to clean it now after the Florida daily afternoon rains pass.

I keep this cover on it. Thoughts?
1629489950620.png

Name plate information.
1629489412756.png

Meter on one leg.
1629489454920.png
 

JamesW

TFP Expert
Mar 2, 2011
28,250
1629490444583.png
Impeller......Total HP.

073126.........0.95
073127.........1.25
073128.........1.65
073129.........2.20
073130.........2.60
073131.........3.45

The total hp is the rated hp x the service factor.

A 1.0 hp motor with a service factor of 1.65 is the same as a 1.5 hp motor with a service factor of 1.1.

A 1.0 hp motor with a service factor of 1.65 is called a "full rated" motor.

A 1.5 hp motor with a service factor of 1.1 is called an "up-rated" motor.

They are both the exact same motor. They both have a total of 1.65 hp.

So, it's confusing to see one listed as 1 hp and the other listed as 1.5 hp.

The key is the total hp, which is what really matters.

Pentair WhisperFlo Model WF-28, 2HP

The WF-28 takes the 073129 impeller, which requires 2.2 hp and the motor is only 1.65 total hp.

You need to downsize the impeller to a 073128, or smaller, or upsize the motor to a total of 2.2 hp.
 
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JamesW

TFP Expert
Mar 2, 2011
28,250
That much current matches the 073130 impeller, which takes a total of 2.60 hp.

Do you know which impeller you have?
 

JoeFletch

Active member
Nov 7, 2014
43
Bradenton, FL
View attachment 365950
Impeller......Total HP.

073126.........0.95
073127.........1.25
073128.........1.65
073129.........2.20
073130.........2.60
073131.........3.45

The total hp is the rated hp x the service factor.

A 1.0 hp motor with a service factor of 1.65 is the same as a 1.5 hp motor with a service factor of 1.1.

A 1.0 hp motor with a service factor of 1.65 is called a "full rated" motor.

A 1.5 hp motor with a service factor of 1.1 is called an "up-rated" motor.

They are both the exact same motor. They both have a total of 1.65 hp.

So, it's confusing to see one listed as 1 hp and the other listed as 1.5 hp.

The key is the total hp, which is what really matters.



The WF-28 takes the 073129 impeller, which requires 2.2 hp and the motor is only 1.65 total hp.

You need to downsize the impeller to a 073128, or smaller, or upsize the motor to a total of 2.2 hp.

This is quite troubling. Here is the name plate information from the pump (note the 2HP).
1629545959033.png

And the original motor (note the 1.5HP).
1629546038960.png
1629546240391.png

So the original motor was 1.5HP while the pump says 2HP. Current motor is 1.65HP.

Also, I moved into the house in 2014 and the motor failed in 2019. So the original motor lasted 5 years and this motor lasted 2 years and 4 months.


That much current matches the 073130 impeller, which takes a total of 2.60 hp.

Do you know which impeller you have?
No. I assume that I would have to pull the pump apart to get that information.
 

JoeFletch

Active member
Nov 7, 2014
43
Bradenton, FL
Now here's something that is even more odd.

My spa has this pump on it (2HP).
1629547330837.png

The original motor said (2HP with a 2.2HP SF).
1629547378407.png

This motor also failed and was replaced with the following.
1629547631483.png

From what @JamesW has shared, it appears that these pumps are the same. But it is possible that the impellors are different and thus the HP requirements are different.

I think the following needs to happen.
  1. Remove pool pump and identify impellor.
  2. Remove spa pump and identify impellor.
  3. Compare pump impellors and identify HP requirements.
  4. If both pumps have the same impellor, swap pump and motor assemblies. (Do not disassemble pump and motor for seal replacement.)
  5. If pumps do not have the same impellor, continue with troubleshooting pool motor.

Let me know if my plan of attack makes sense here.

On a side note, it's amazing how this stuff comes up when you are leaving home to travel for work!
 

JamesW

TFP Expert
Mar 2, 2011
28,250
The 355024S 1-1/2 HP motor is correct for the WF-6 and WF-28 pump because it has a total hp of 2.2.
 

JoeFletch

Active member
Nov 7, 2014
43
Bradenton, FL
The pump was made in 2010, but the motor was made in 2014, so it is not the original motor.

You need to see what impeller you have.
Yeah, the more I look at this, the more I notice that something is not right.

How much flow do you need?
I have no idea! I never received any documentation from the previous owner.

I also called Pentair (they are available on a Saturday). I gave them the original model and serial number off of the pump. They said that I need a 355024S 1.5HP (SF2.2) motor. So I am WAY undersized on this motor. I guess initially, this motor worked but over time, it has finally got to a point where it cannot keep up any longer. If I understand your original post, it appears that I need a total of 3.3HP.

What's odd is the the original nameplate did not have any of the HP or SF details. So I guess this is on me for not calling and making sure that I have the right motor.
1629552409752.png
 

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JamesW

TFP Expert
Mar 2, 2011
28,250
You need to see what impeller you have.

The motor has been replaced at least twice and the impeller was probably replaced and you don't know what impeller is on there now.

Can you show a picture of the system?

Do you need a lot of flow for some reason?
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
44,347
Laughlin, NV
Pool Size
6000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
What vacuum type do you use?
 

JamesW

TFP Expert
Mar 2, 2011
28,250
The impeller is what determines how much total hp you need.

Impeller......Total HP.

073126.........0.95
073127.........1.25
073128.........1.65
073129.........2.20
073130.........2.60
073131.........3.45

Based on the current motor, you can use one of the following impellers.

073126.........0.95
073127.........1.25
073128.........1.65

I would go with a 073127
 

duade

Well-known member
Aug 11, 2020
55
Chicago
I live close to in the swim in West Chicago. On more than one occasion I've been in the outlet store with a customer complaining about a Pentair refurbed pump that does not have the impeller that the pump advertised.

Unless you check for sure yourself, you don't know what impeller is in there.
 

JoeFletch

Active member
Nov 7, 2014
43
Bradenton, FL
I live close to in the swim in West Chicago. On more than one occasion I've been in the outlet store with a customer complaining about a Pentair refurbed pump that does not have the impeller that the pump advertised.

Unless you check for sure yourself, you don't know what impeller is in there.
Yeah, I am seeing more and more of the issues with Pentair...(I've had salt cell issues too...)
 

JoeFletch

Active member
Nov 7, 2014
43
Bradenton, FL
The impeller is what determines how much total hp you need.

Impeller......Total HP.

073126.........0.95
073127.........1.25
073128.........1.65
073129.........2.20
073130.........2.60
073131.........3.45
Looks like I have a 073129. So according to your details above, I need a 2.2HP motor.
1629555487195.png


Based on the current motor, you can use one of the following impellers.

073126.........0.95
073127.........1.25
073128.........1.65

I would go with a 073127
Why would you suggest a 073127? Keep the impellor undersized for the motor?
 

JamesW

TFP Expert
Mar 2, 2011
28,250
Unless you need a lot of flow, there is no reason to have a pump that big.

A 073126 or 073127 should be plenty of flow.

You can undersize the impeller for the motor, but you can't undersize the motor for the impeller.
 
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