Pump Motor Cycling

JoeFletch

Active member
Nov 7, 2014
43
Bradenton, FL
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.
Totally make sense.

Where are you getting the impellor information?

I know that this is a tough question but if I change the impellor, do you think that I can still get some life out of this motor?
 

JoeFletch

Active member
Nov 7, 2014
43
Bradenton, FL
You should take the impeller off and then take the seal plate off of the motor to make sure that everything is ok.

Maybe just get a new variable speed pump.
Yeah, lots of options. None of them cheap.

From the local pool supply store...

Replace the impellor, $110

Replace the motor, $400

The joys of owning a pool! Haha.

Here's another option to get me through the week (because I am traveling for work). Take my spa pump motor combination apart and if it has the 073129 with a 2.2HP motor, I can install it on my pool side and be good to go. Thoughts? (I am going to go and check this now.)
 

JamesW

TFP Expert
Mar 2, 2011
28,262
I would replace the whole pump with a variable speed pump.

That pump has multiple issues that will be a problem.

Even accounting for the impeller size, the amperage is too high.

So, the motor is bad or something is binding.
 

JamesW

TFP Expert
Mar 2, 2011
28,262
This is the seal plate.

The motor bolts to the seal plate.

Sometimes the brass grommets come loose and the motor pulls back, which causes the impeller to rub on the seal plate and/or the diffuser.

Based on the amperage, the impeller is probably rubbing. It's also possible that the excessive load has damaged the motor.

You can replace the impeller and seal to see if the pump will work, but I would probably just replace the pump with and intelliflo variable speed pump and forget about the old pump.

Whisperflo seal plate.jpeg
 

JamesW

TFP Expert
Mar 2, 2011
28,262
You can see scratches on the impeller, which indicate rubbing.

The excessive load and the rubbing finally caused the motor to overheat enough to shut down.

Most likely, the seal plate is bad.

The cost for a seal plate, impeller, seal etc. are too much considering that the motor is likely damaged.

You current pump has been using about 2,500 watts.

A variable speed pump will use closer to 250 watts, which is 1/10th the amount of power.

That will reduce the power bill and offset the cost of a new pump.

1629568441377.png
 
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JoeFletch

Active member
Nov 7, 2014
43
Bradenton, FL
This is the seal plate.

The motor bolts to the seal plate.

Sometimes the brass grommets come loose and the motor pulls back, which causes the impeller to rub on the seal plate and/or the diffuser.

Based on the amperage, the impeller is probably rubbing. It's also possible that the excessive load has damaged the motor.

You can replace the impeller and seal to see if the pump will work, but I would probably just replace the pump with and intelliflo variable speed pump and forget about the old pump.
I follow you. I did not check those bolts. Figured it was best not to touch them. I will have to budget for this in the near future. Based on how my piping is laid out, I think that most of the fittings will need to be replaced.

I did swap the pumps out (spa to pool) and I am up and running again until I can parts.

What is the average life of pumps, motors and filters? Roughly speaking that is. My filter housing has seen better days and I think that it is only a matter of time before that fails.
 

JoeFletch

Active member
Nov 7, 2014
43
Bradenton, FL
You can see scratches on the impeller, which indicate rubbing.

The excessive load and the rubbing finally caused the motor to overheat enough to shut down.

Most likely, the seal plate is bad.

The cost for a seal plate, impeller, seal etc. are too much considering that the motor is likely damaged.

You current pump has been using about 2,500 watts.

A variable speed pump will use closer to 250 watts, which is 1/10th the amount of power.

That will reduce the power bill and offset the cost of a new pump.

View attachment 366153
Great catch. I didn't notice that when I had it apart. I appreciate you continuing to look into this!
 

NowintersinAZ

Well-known member
Oct 18, 2020
177
Mesa, AZ
Pool Size
7560
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
Intex Krystal Clear
When replacing a motor where the system calls for 1.5 hp you buy a 1.5 hp motor not a 1 hp motor with a service factor of 1.65.
This service factor can be used for the following:
  1. To accommodate inaccuracy in predicting intermittent system horsepower needs.
  2. To lengthen insulation life by lowering the winding temperature at rated load.
  3. To handle intermittent or occasional overloads.
  4. To allow occasionally for ambient above 40°C.
  5. To compensate for low or unbalanced supply voltages.
NEMA does add some cautions, however, when discussing the service factor:
1. Operation at service factor load for extended periods will usually reduce the motor speed, life and efficiency.
2. Motors may not provide adequate starting and pull-out torques, and incorrect starter/overload sizing is possible. This in turn affects the overall life span of the motor.
3. Do not rely on the service factor capability to carry the load on a continuous basis.
4. The service factor was established for operation at rated voltage, frequency, ambient and sea level conditions.

You can find the info here.
 

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JamesW

TFP Expert
Mar 2, 2011
28,262
When replacing a motor where the system calls for 1.5 hp you buy a 1.5 hp motor not a 1 hp motor with a service factor of 1.65.
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.

Service Factor is being eliminated.
 

NowintersinAZ

Well-known member
Oct 18, 2020
177
Mesa, AZ
Pool Size
7560
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
Intex Krystal Clear
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.

Service Factor is being eliminated.
Using sf x hp to rate a motor will result in premature motor failure.
They are not the exact same motor one is a 1 hp motor with a sf of 1.65
and the other is a 1.5 hp motor with a sf 1.1
in 30 years in the electrical industry we have never sized a motor with the sf included into the hp.

That is not what the sf is for, sf is for allowing for temporary variables during the life of the motor.
 

NowintersinAZ

Well-known member
Oct 18, 2020
177
Mesa, AZ
Pool Size
7560
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
Intex Krystal Clear
Total Horsepower or Service Factor Horsepower (SFHP) is required to be labeled on each pump.

THP or SFHP is the new HP rating determined by the total horsepower created at the motor shaft.

I see this is new as of 7/18/2021
Just because someone makes a regulation or changes a code doesn't make it smart.

It also states when replacing a motor you don't have to follow the regulations if the motors are still available. It's only for new manufactured pumps.

With the new information I will stand down but disagree with it, I believe it will lead to premature motor failure as the motor will be operating in an over worked scenario.
 

JamesW

TFP Expert
Mar 2, 2011
28,262
They are not the exact same motor one is a 1 hp motor with a sf of 1.65
and the other is a 1.5 hp motor with a sf 1.1
The OP has a WF-28, which is listed as a 2 hp pump with a service Factor of 1.1 for a total hp of 2.2.

The WF-6 is the Exact same pump and it takes the Exact same motor even though the WF-6 is listed as a 1.5 hp with a sf of 1.5 for a total of 2.2.

Every part is exactly the same.
1629587569604.png
1629587887751.png

1629588227586.png
 

JamesW

TFP Expert
Mar 2, 2011
28,262
The WF-3 and the WF-24 both take the same motor even though they are listed as different label hp and SF because the total is the same.

The WF-4 and the WF-26 both take the same motor even though they are listed as different label hp and SF because the total is the same.

1629588866265.png
 
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