Whisper Flo impeller size

Jump to latest Follow Reply
fordsbyjay

fordsbyjay

LifeTime Supporter
Sep 1, 2009
78
Lafayette, LA
I have a Whisperflo WFE-2 1/2 hrsp pump on my pool. The seal plate had broken at the mounts so I ran all over town yesterday to buy a new one. Then I went to change the seal in the impeller and I broke the impeller housing. I've changed them before but this one was welded in the impeller. After breaking a piece of the impeller I put it in a vice and had to hammer it out. After calling around nobody locally had an impeller for a 1/2 hspr motor, all I could find was a 3/4, 1 and 1 1/2 hspr impeller. I needed to get this thing going so I purchased the 3/4 hspr one. What I seen in my travels were the 1 1/2 ones are wider but the same/close OD as the 1/2 hspr unit at 4 1/2". The 3/4 hspr impeller was was the same width as the 1/2 hspr unit but 3/8" larger at 4 7/8" OD.

I have a timer on our pool and at start up it always seemed like it took awhile to prime. With the larger 4 7/8" OD impeller it primes right now and it seems like there is more pressure at the jets (based on the splashing on the pool surface). I am not sure of any long term issues it may cause but I guess we will find out. Maybe someone else will have some experience they can share. If now we will find out. Anyways I am just sharing in case someone else gets in the same predicament.

impeller chart.jpg

broken impeller.jpg
 
In the Whisperflo line, the 1/2 HP Pump and the 3/4 HP pump use the same motor so I think you should be ok.

27 355008S 3/4 HP, 60 Hz, WFE-2, 3 & 24, 1 spd., almond, 31 lbs.
Click to expand...

The 1/2 HP is just under loaded by a bit.
 
  • Like
Reactions: fordsbyjay
They use the same replacement motor, but I think that the original motors are different.

The original motor on the 1/2 hp has a total of 0.95 hp.

The original motor on the 3/4 hp has a total of 1.25.

The replacement motor is for a 3/4 full rated pump or a 1 hp up rated pump. They list it for the 1/2 hp, but it's stronger than the original 1/2 hp motor.

The 073127 impeller requires a total of 1.25 hp. If the original motor is a total of 0.95 hp, the 073127 impeller is going to put excessive load on the motor.
 
Here is the label for the 355008S it is a 1 HP motor with a SF of 1. They may have originally put a larger than necessary motor on the WFE-3. It think it should be just fine.

41EEd0Km0UL.jpg
 
That label does not show a horsepower or service factor.

Here’s what it says on the Whisperflo page:

WFE-2... Full Load Amps 8.8/4.5-4.44, HP 1/2, SF 1.90, SFHP 0.95

WFE-3... Voltage 115/208-230, Full Load Amps 11.2/6.0-5.6, HP 3/4, SF 1.67, SFHP 1.25

WhisperFlo® High Performance Pump

fordsbyjay, do you have a picture of the original motor label?
 
Last edited:
Even if we conclude that the Service Factor is 1.0, we still don’t know what the H.P rating is. All references say that the total hp is 1.25. So, maybe the hp is 1.25 with a sf of 1.0.

In any case, it’s possible that the original motors are the same, but I don’t think that it can be conclusively established based on the available information.

If they are the same, then it should be fine. If they are not the same, then the motor is being overloaded.

If the original motor label amps are 8.8/4.5-4.44, then I would downsize the impeller.

If the original motor label amps are 11.2/6.0-5.6, then it should be fine.
 
  • Like
Reactions: fordsbyjay
Even if they are not the same, the motor may still not be overloaded. In fact most pool pump motors are never loaded to full rating. It depends on the operating point on the head curve. Plus they usually build in some extra margin so I would be very surprised if a motor operated anything above 95% actual full loading.

Also, if the motor is being overloaded, the worst thing that would happen is that the thermal limiter would switch the motor off. Then you know for sure.
 
Last edited:
  • Like
Reactions: fordsbyjay

Enjoying this content?

Support TFP with a donation.

Give Support
That is exactly the same replacement motor for the WFE-3 so there should be no reason that it doesn't work.
 
The replacement for the WFE-3 is part number 196232, model number 355008S with amps at 7.0 - 6.4.

The original WFE-3 amps are listed as 6.0 - 5.6.

The existing motor is part number 196237, model number 355018S with amps listed as 5.4 - 5.2.

So, the existing motor can take up to 5.4 amps, but the original WFE-3 could take up to 6.0 amps.

It's close, but I would consider the current motor to be slightly overloaded.
 
I understand that but amp ratings are very loose to begin with. NEMA amp ratings have a tolerance of ± 10%. So they are not absolute limits.

How Precise Are Motor Nameplate Ratings?

Another possibility is that the newer motor is more efficient so it takes less amperage for the same load.

Plus I don't think Pentair would have suggested that motor as a replacement for the WFE-3 if it wouldn't work. That just doesn't make any sense.
 
Last edited:
As long as the motor is not getting excessively hot or exceeding the amperage as specified on the label it should be fine.

Assuming you are measuring surface temperature, in the shade, at air temperatures less than 90 F, I would give this as a rough guide:

Below 135 F, good
135 to 150 F, warm
Over 150 F, too hot.

You can use an amp-meter to measure amperage or a non-contact temperature sensor to check the motor temperature.

I would estimate the amperage to be in the 5.2 to 5.7 range depending on the voltage. If the voltage stays close to 240, then I would estimate the amperage to be at the lower end. If the voltage stays closer to 220, then I would expect the amperage to be closer to the higher end, but it's just a rough estimate.
 
Last edited:
  • Like
Reactions: fordsbyjay
No disagreement except that a motor can exceed NEMA amperage ratings by up to 10% and still be within compliance. The only true limit on a motor label is the THP rating. Amperage is not always a good metric to use for determining if a motor is overloaded. It can only give you a sense if there might be a problem. However the thermal limiter is a very good indicator if the motor is overload.

But again, it sounds like you don't trust Pentair's replacement motor recommendation. That does not seem logical. If that motor was undersized, they would have received thousands of returns by now and would have most certainly changed the recommendation.
 
The replacement motor that they have is designed for the WFE-2. Part number 355018S.

The replacement for the WFE-3 is part number 355008S.

It's two different motors.

The 355008S can be used on the WFE-2 but the 355018S is undersized for the WFE-3.
 
The OP has the 355018S motor, which is only specified for the WF-2 or WF-23 (073126 impeller), but they now have a WFE-3 impeller (073127).

So, they need the more powerful 355008S motor or they need to downsize the impeller back to the 073126 impeller.

The 355018S has a total hp of 0.95.

The 355008S has a total hp of 1.25.
 
Last edited:

Enjoying this content?

Support TFP with a donation.

Give Support
You must log in or register to reply here.
Thread Status
Hello , This thread has been inactive for over 60 days. New postings here are unlikely to be seen or responded to by other members. For better visibility, consider Starting A New Thread.
Top Bottom
Back
Jump to latest Follow Reply