[SOLVED] Pentair Whisperflo Suddenly Quit Working - Capacitor


Bronze Supporter
Nov 14, 2017
Marietta, GA
Hello everyone,

I've resolved my issue and thought I would share just in case anyone else comes across this. I have a 5-year old Pentair Whisperflo (1.5 HP) (Model #011518). About 3 days ago it came to my attention that my pump wasn't running. I went back to the control box and verified that the system was powered and other equipment functioned. The pump was super hot to the touch, I couldn't keep my hand in it for more than a few seconds. I shut the power off for a few hours thinking maybe it over heated somehow. I checked the basket at the pump and there wasn't anything stuck in the pump: there was not. After a few hours I tried the pump again and it made a loud humming noise for a few seconds then shut off, it immediately heated up again. So back to the the internet I went searching for this model and what could be causing it. I verified the impeller could spin but putting a long screw drive into the pump and spinning it both ways.

A few YouTube videos indicator that it might be the RUN capacitor that sits in the little bulge cabinet on the back of this pump. I found one on Amazon for $12 but it was going to take too long to ship to me, so I went to my local Leslie's Pool Supplies and had them match the capacitor for $30.

After powering down the system and discharging any residual energy from it, I replaced the capacitor with a new one and VOILA, the pump motor runs again on the first try. The capacitor wiring connectors takes 30 seconds to detach and reattach with no tools. Your RUN capacitor rating will vary in uF rating and all the advice I've seen indicates you should get an exact replacement and not try to size it up or down because its matched to the motor perfectly. Its also important you get a capacitor that has similar dimensions so it fits in the little housing on the back of the motor.

Posting a picture of the old capacitor and the motor housing if it helps anyone in the future.

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