WhisperFlo won't start when diffuser assembly is installed

[satpoolguy]

I have 2 WhisperFlo pumps for waterfalls that weren't used all summer (they were last used when the anti-freeze cycle activated, likely in March or so). Last week I tried to use them, and neither turned over -- they just hummed. I disassembled one of them, verified no blockage, and that the impeller turns freely (although with some resistance -- I'm not sure if it's a normal amount or not). If I turn on the pump without the diffuser assembly attached, it runs fine. I thought the diffuser assembly may have warped or something, so I bought a brand new one, but the pump still won't run with it on (still runs fine without it). What are the likely culprits? It appears that the starter capacitor is OK based on my testing (but I have found that test to be inaccurate in other situations).

added 12/2016 -- pls see post 11 for an update and new question

 

[mas985]

Does the motor spin freely when the diffuser is installed?

 

[btolley]

Shot in the dark; i had a problem where the motor was not perpindicular to the seal plate and interferred with the impeller. So the motor would spin freely until it was attached to the seal plate, then just a hum. Just a suggestion of someplace to look.

 

[satpoolguy]

Does the motor spin freely when the diffuser is installed?

You know, embarrassing as this is, I'm not sure if i explicitly tested this...will need to do so when I get back to the pump this weekend (traveling now).

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Shot in the dark; i had a problem where the motor was not perpindicular to the seal plate and interferred with the impeller. So the motor would spin freely until it was attached to the seal plate, then just a hum. Just a suggestion of someplace to look.

I'm not even reattaching the motor to the seal plate...just trying to let it run standalone (and yes I know I can do that only for very, very short periods of time without causing damage due to overheating)

 

[satpoolguy]

Does the motor spin freely when the diffuser is installed?

Just checked on this...it does spin when the diffuser is installed, although it requires significantly greater force to spin it. Certainly some additional force would be expected because of the contact between the impeller and the diffuser.

 

[mas985]

The impeller should fit fairly loosely inside of the diffuser plus the impeller ring acts like bearing so there should not be any extra force on the impeller. BTW, did you check the impeller ring? On the Whisperflo it is a ring that fused inside the diffuser.

 

[satpoolguy]

Shot in the dark; i had a problem where the motor was not perpindicular to the seal plate and interferred with the impeller. So the motor would spin freely until it was attached to the seal plate, then just a hum. Just a suggestion of someplace to look.

And it turns out that I didn't know what the seal plate is...I did still have it attached. The bottom 2 bolt holes were basically completely eroded, so I'm hoping that this is causing an alignment issue like you had and I can replace the seal plate and be back in business. That would also explain why the diffuser was a bit of a pain to seat properly. I am going to order a new seal plate and see if that addresses the issue.

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The impeller should fit fairly loosely inside of the diffuser plus the impeller ring acts like bearing so there should not be any extra force on the impeller. BTW, did you check the impeller ring? On the Whisperflo it is a ring that fused inside the diffuser.

That's definitely not what I am observing. I did check the impeller ring (which is brand new on the new diffuser, shiny copper color). Hopefully replacing the seal plate will do the trick.

 

[timerguy]

I just recently replaced my whisperflo. I had thought the shaft was spinning freely. But, when the dealer came out to replace my motor, he found it wasn't spinning freely, and the seal plate had cracks in the bottom two attach holes. I had already checked my capacitor which I had just replaced back in March. So figured it had to be the motor. The cost of the motor and seal plate made the price of a new pump worthwhile.

 

[btolley]

Yep, the bottom holes errode and that is what causes the motor to "sag" against the seal plate. I think that will solve satpoolguy's problem.

 

[satpoolguy]

Yep, the bottom holes errode and that is what causes the motor to "sag" against the seal plate. I think that will solve satpoolguy's problem.

And indeed it did, for one of the pumps! Thx everyone!

i am going to order the seal plate and required shaft seal for the other pump and expect to encounter success there, too.

 

[satpoolguy]

Reviving this old thread b/c I am having the exact same issue again, just 2 years later. Is that normal??? Is there anything that can be done to prevent the seal plate from eroding? Would running the pump more often help?