Pentair 1.5 hp pump will not start

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J

juancapool

Member
Sep 2, 2022
12
Miami
Hi,
new to this forum and looking for some help with pool pump that will not start. It is a Pentair 1.5 hp pump (Model SF-N1-1-1/@A/340039). I did the following:
  1. Replaced the 30microfarad capacitor with a new one
  2. Checked the impeller and it is loose, it moves freely.
  3. Each motor leg has 120v and 240v across.

But it wont start. Sounds like a dead motor, but before I purchase a new one, is there anything else I can check to insure it is dead dead??

Many thanks for any feedback.
PXL_20220902_204750306.jpgPXL_20220902_204735502.jpg
 
Ok, my point on the capacitor is that if the windings open while the motor is running, the capacitor can be left charged and it will spark when discharged.

However, if the motor windings are good when the motor is turned off, the capacitor will discharge through the windings and there will be no spark when the capacitor is discharged.

In any case, the readings seem to indicate a bad motor.

You were definitely getting 240 when measuring from line to line, correct?
 

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Yeah on most meters the 0L is open circuit, which is bad.

So the next thing you can try is remove the rear housing. See this video toward the end for the rough idea. If there's obviously broken wiring there, it might be repairable.

In the big picture 9 years is a pretty full life. Even if you get it going again, it may not be long before something else.

Same pump came with our pool 2 years ago. It's a beast. Flow meter showed it pumping 105 gallons per minute. Replaced it with a VSP this summer. Much more sane.
 
Last edited:
JamesW said:
Ok, my point on the capacitor is that if the windings open while the motor is running, the capacitor can be left charged and it will spark when discharged.

However, if the motor windings are good when the motor is turned off, the capacitor will discharge through the windings and there will be no spark when the capacitor is discharged.

In any case, the readings seem to indicate a bad motor.

You were definitely getting 240 when measuring from line to line, correct?
Click to expand...
Yeah. 120v to each leg and 240 across both. The timer is putting out power.
 
generessler said:
Yeah on most meters the 0L is open circuit, which is bad.

So the next thing you can try is remove the rear housing. See this video toward the end for the rough idea. If there's obviously broken wiring there, it might be repairable.

In the big picture 9 years is a pretty full life. Even if you get it going again, it may not be long before something else.
Click to expand...
Good point. One thing is that the motor shaft is loose both fwd and backwards so there's nothing physical impeding rotation.
 
I would say that the motor is dead.

I would switch to a variable speed pump like the SuperFlo VST or IntelliFlo VST.

If you want to take the motor apart to see where the break in the windings is, that would be interesting if you can share.
 

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