Old and new pump motor both shut down after a few seconds

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M

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Aug 14, 2021
20
Florida
Experts, my old and rusted out motor started shutting down every a few seconds. After several more seconds the thermal switch cooled off, clicked and the motor turned on again.

Considering the motor and pump age and condition I assumed they were at the end of the lifespan so I have bought and installed a new motor-pump combo (increasing slightly the power from 1.25 to 1.5 HP, both at 110V).

The new motor and pump unfortunately shut down in exactly the same way. So I'm guessing some pipes could be plugged up. I disconnect the output outlet from the pump, connect a pipe leading out into the open space, and let the pump run. The water is gushing freely for a few seconds, and the motor shuts down again. Cools off, clicks, and runs for a few seconds etc. I keep the motor covered in a shade and even put some ice-packs on it to ensure no ambient influence.

So it's not a blockage in the outlet piping. I'm looking at the inlet - could be either from the skimmer or the pool bottom. I set the valve to skimmer - same shut down problem. I set the valve to draw from the pool bottom - same problem. Not likely that both pipes plugged up in the same way at the same time. So I disassemble the common denominator - skimmer/bottom selector valve - clean and working correctly, no problem here.

Any ideas for the next step in troubleshooting? Thanks for any advice!!!
 
Welcome to TFP! :wave: You listed a few water/plumbing troubleshooting procedures, but your issue seems to be electrical. Why it just started happening and why to both the old and new motor would be the mystery. Have you tried measuring the voltage provided to the pump to see if you indeed are receiving a correct ~ 110V? Perhaps a breaker has failed back at the breaker panel? Maybe also post some pics of your pool pump, motor, and equipment pad. We might also need to see a pic of the power supply for your pump (i.e breaker box, timer, etc).
 
Hello, so the voltage at the pump is a constant 120V at no load, going down to constant 114V under load. What is amazing that the current under load is a constant 34A at the pump, which seems way too high. I'll post some photos shortly.
 
Does the pump wiring look correct? Obviously manufacturer is incorrect showing both L1 and L2 as Line for 115V and adding it's "NON REVERSIBLE". Printed manual says "Neutral on L1 and Line on Terminal 3 of L2" which is not clear as there is no marking of Terminal 3 anywhere.

So I've connected Neutral to L1 and Line to L2. (Unless Terminal 3 would be a third unmarked connection next to 115v-220V selector).

1) I'm guessing that one possibility could be that both old and new motor gave the same symptoms (shutting down after a few seconds) but the old one could be shutting down due to bad bearings and the new one due to incorrect wiring.

2) Another possibility is that both skimmer and bottom pipes plugged themselves at the same time and they both don't provide enough flow. I may run a new ground level pipe from the pool to the pump input to check it.

Both possibilities are not very plausible, any other thoughts or advise?

Also there is some EnergyWise smart box on the right to the breaker box, installed by the power company, but I don't think it could be a problem (or could it?)

Thanks!!!
 
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JamesW - thank you for your comments, amperage measured using the clamp meter pictured, the box on the right is a power company gadgetry which is supposed to be helping them load balance the network. All wiring done by previous owners so no clue why they did 115V, I just followed.​

But maybe doing a 220v is a good idea - bypassing all the Crud and just running one line directly and the other through the mechanical timer - is it what you would recommend?

thanks
 

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The centrifugal switch looks defective.

The contacts should be closed when the pump is off and they should open when the motor reaches speed to take the capacitor out of the circuit.

1629137624938.png
 
The motor type etc numbers are at the top photo, amperage checked on a single Line wire going from the box to the pump, don't know if the shaft turns freely as I don't see how to try to rotate it by hand, will look at the pump again
 
I've shot a video of the centrifugal switch up close during operation (video too large to post) and it shows the switch closed when the motor is off, it opens when the motor starts running and closes again when the motor stops. So it does appear to operate correctly.
 
Now connected a new surface pipe from the pool to the pump and let the pump push the water out of the pool onto the ground with nothing in the way except a straight pipe - exactly the same results.

So I will now rewire it to 230V unless someone has a better idea, thanks.
 
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