Near-new pump buzzes - won't run

ToddGak

Active member
May 19, 2018
32
Saratoga Springs, NY
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

TFP Expert
Mar 2, 2011
25,897
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.
 

JamesW

TFP Expert
Mar 2, 2011
25,897
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

Active member
May 19, 2018
32
Saratoga Springs, NY
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

TFP Expert
Mar 2, 2011
25,897
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

Well-known member
Aug 20, 2017
217
Southeast PA
Ok, it would be odd for it to fail so soon, but it's an electronic component and they can fail at any time.

1200px-Bathtub_curve.svg.png


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

Active member
May 19, 2018
32
Saratoga Springs, NY
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.
 

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ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
26,458
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
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

Active member
May 19, 2018
32
Saratoga Springs, NY
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

Well-known member
Jul 28, 2019
135
Northwest ohio
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

TFP Expert
Mar 2, 2011
25,897
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.
 
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