Near-new pump buzzes - won't run

[ToddGak]

I ordered a new sand filter and pump from poolsupplyworld.com and have had it installed and running great for about a week. The pump is a 2-speed Pentair Dynamo (DYNII-N2-1-1/2). I have been running it on low speed almost constantly for a week. Have tried high speed just to see that it works, but haven't used it for more than a minute at a time.

Today I wanted to add CYA, so I put the CYA in a stocking and put it in the skimmer basket. I decided to turn the pump on high speed for a few minutes to get the water really flowing to start dissolving the CYA. I turned on high speed and it seemed to be running fine. I ran it for a minute or so, then turned the pump off. When the motor stopped I turned the switch to low speed and the motor began buzzing and didn't turn.

In trying to diagnose the problem, I checked the breaker. It didn't trip, nor did the GFCI on the breaker. I tested the GFCI, cycled the breaker. Both seem fine. I cleaned the little bit of debris out of the pump's basket. I took the back cover off the motor. The impeller turns freely with a screwdriver. I turned the switch to low speed, and with the motor buzzing, gave the shaft a spin with a screwdriver. It actually turned for several seconds at a slow speed, but decelerated and stopped.

Any idea what the problem could be? Capacitor? Since it is new, should I just get a warranty repair? Thanks!

 

[JamesW]

Check the voltage at the pump line to line to make sure that the voltage is correct.

If it is, you can try a new capacitor or ask for a replacement under warranty.

 

[ToddGak]

Just checked the voltage at the outlet - 122vac

 

[JamesW]

Is that the correct voltage that's specified on the motor label?

If yes, check voltage directly on the motor terminals.

If correct, I would suggest a warranty replacement.

 

[ToddGak]

I was just able to "jump start" it with a screwdriver by manually turning the shaft at the same time I switched it on.

Before that, I measured line to ground on the motor itself and got 120, which is good. Was trying to figure out how to safely check line to line when on a whim I tried the screwdriver start method. I'm going to order a new capacitor.

 

[JamesW]

Does the pump have a capacitor?

 

[ToddGak]

Sure does

 

[JamesW]

Ok, it would be odd for it to fail so soon, but it's an electronic component and they can fail at any time.

 

[kchinger]

Ok, it would be odd for it to fail so soon, but it's an electronic component and they can fail at any time.

Bathtub curve. Usually things die early or they last a long time. His died early. Likely there were signs at the factory but their QC either missed it or didn't check at all.

 

[ToddGak]

Well, I replaced the capacitor. It did not fix the issue. I need to further troubleshoot the problem, but I can not find a complete wiring diagram for the motor with the documentation that came with it. Does anyone know where I can find that? I googled but haven't found it.

I have a Pentair Dynamo 1-1/2HP 2-Speed, 115V

Again, the motor itself runs fine on both speeds, but only if I manually turn the shaft with a screwdriver when I switch the motor on.

 

[ajw22]

Again, the motor itself runs fine on both speeds, but only if I manually turn the shaft with a screwdriver when I switch the motor on.

Go for a warranty repair.

I am not sure of the technology used in that motor. But in motors that use brushes if the windings get a dead spot the motor will not start until rotated. Then the momentum keeps it spinning over the dead spot and it looks like everything is working fine.

 

[ToddGak]

Will try... I installed it myself and according to PoolSupplyWorld, the warranty is for 60 days from the delivery date, even though it was delivered a while before I even opened my pool for the season.

 

[Chad1979]

I cant tell you for sure as I'm not an elecrician. I work in a factory with many many types of motors. It may be a type of "phase short" motor wont start up when they stop and are in a location where the phases short each other out. But if you rotate he motor some it wil start up. I have seen it a few times and maintenance replaces the motor an sends that one out for a rebuild. Dont know if thats whats hapening to yours but from seeing something similar at my work its just a thought i had.

 

[JamesW]

If it's not the capacitor, it's probably a bad centrifugal switch.

The pump should be under warranty. File with the seller. If they won't do anything, file with the manufacturer. If they won't do anything, file a claim with the motor manufacturer.

 

[ToddGak]

If it's not the capacitor, it's probably a bad centrifugal switch.

It was the centrifugal switch. I manually actuated the centrifugal switch a few times, then the motor started right up. Assuming I cleaned some dirt or corrosion off of the contacts. Wish I tried this several weeks ago.

Thanks