Pentair whisperflo pump hums then starts

Msm

0
Jan 4, 2013
2
My 2hp pentair whiperflo pump hums initially when turned on. I turn the pump on and off a few times letting it hum for a few seconds each time. The pump will then eventually start. After the pump is up and running, it sounds normal and everything appears to be functioning. The capacitor has been changed with same results. I can't move the impeller by hand even though nothing is stuck in the impeller. I can move the impeller using a wrench on the rear shaft.
 
Welcome to TFP!

That sounds like a problem with the shaft bearings. The shaft should turn fairly freely by hand. If it doesn't, there is either something blocking the impeller, or the bearings are failing. If there was something blocking the impeller, it would most likely have cleared up once you got the pump running a single time, so the most likely problem is the bearings.

Bearings tend to fail slowly. You might well have a year or two of life left in the bearings, or more, all be it with more and more difficulty getting the pump to startup. Typically startup problems are worst when it is cold and/or when the pump hasn't been run recently, so you might not notice any problems during most of the summer.

The bearings can be replaced if you are mechanically inclined, or you could have a motor shop rebuild the motor, or you could replace it. When replacing the bearings you also need to replace the shaft seal.
 
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