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dreamweaver7419

Pump run on reversed hot and neutral

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I have a circulating pump (UPS15-58FC, 3-Speed Circulator Pump, 1/25 HP, 115 volt) that I had running for a month or so off and on a timer.  Later I discovered that the outlet that I had the pump running off of had a reversed hot and neutral wire.  After plugging into another outlet that didn't have a reversed hot/neutral the pump seemed to start up fine.  I left it for a day and tried it again and the breaker tripped.  Is my pump ruined?  How do I check?  I verified that the pump is wired correctly,

A little more detail.  I discovered the above when I ran the pump on a temperature controller.  The pump would come on even when the controller was off.  As stated above, when I got power from an outlet without the hot/neutral reversed yesterday, the controller hit its setpoint and the pump came on.  Today, the controller hit its setpoint and from the sound of it got fried.  Then I tried plugging the pump directly into the outlet and tripped the breaker.

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Reversed polarity should not have caused any damage to the circulator. If it's damaged, something else did it. 

Grundfos pumps are very durable, but they tend to fail when their motor shafts are not installed horizontally. Was this one installed properly? 

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Yes.  I did take care to make sure the shaft was horizontal.  After discovering the hot/neurtral reversal, I did run the pump on an extension cord to an outlet that was not reversed.  I just thought about checking the voltage to make sure it wasn't too low, but the pump draws lesss than 2 amps I believe, so I don't think that would cause the problem.  The breaker also tripped quickly.  I just want to make sure if I have to buy another pump, that I don't fry this one.  But if there is a way to salvage this one, I would like to know how to check.

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If that motor is a shaded pole motor, it might run backwards if the shaft happens to be rotating in that direction when power is applied.  I don't know if there is a check valve on the pumps to prevent water from flowing backwards when the pump hasn't power.

I sometimes diagnose defective run capacitors on AC condenser motors by manually spinning the fan blade with power applied.  Occasionally, I'd get the rotation wrong and the fan would come up to full speed running backwards.

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Look for a short in the circuit if the breaker trips with the pump disconnected, otherwise a defective pump motor or defective breaker.

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Did you go back to the original outlet that was running the pump for a year?

Make sure the cord and plug are not damaged from being shifted around .  The motor ran normally with neutral on the switch because it is 120 volt alternating current, not really 'polarized'.

 

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I agree something has changed other than polarization of power. Since you are on a different outlet, maybe it was too close to being overloaded and the pump sent it over the edge.... but I think Marc is more on the right track.

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