Definitely NOT the capacitor

[Giant655]

Figure this one out everyone.
3/4 hp pentair pinnacle, been in this house 10 years so it was here before me.
Last 2 summers I've had to replace the capacitor because it died (obviously lol). Today however! Heard my pump click like it was trying to turn on but the capacitor was dead. Havent opened my pool yet, or tried to turn the pump on for the season. Motor is hot to the touch, lord only knows how long this has been doing it. Here's the kicker, I pulled the capacitor in an effort to diagnose what's happening. Still getting the familiar hum then kick, WITHOUT a capacitor installed. Nothing else has signs of wiring failing or needing attention. Is this an electrical issue, or is this what pumps do on their last leg?

 

[ol_whistle_britches]

Put a wrench on the shaft. Does it spin freely?

@Jimrahbe - internal winding short? Cracked impeller?

 

[TinFoilHat]

You KNOW it's not the capacitor? If the cap is bad the motor will sound the same with or without the cap on it. Chinese caps....

 

[MSchutzer]

It’s likely the capacitor. A capacitor often fails open, so the motor will behave the same way if you have an open capacitor, or a missing capacitor.

The hum is from the excessive current being drawn when the rotor isn’t spinning. The capacitor provides a phase shifted voltage so that the rotor will spin.

Replace the capacitor.

 

[JamesW]

Still getting the familiar hum then kick, WITHOUT a capacitor installed.

That tells you nothing.

Show the capacitor.

Try a new capacitor.

 

[Giant655]

You KNOW it's not the capacitor? If the cap is bad the motor will sound the same with or without the cap on it. Chinese caps....

But its doing this with the power switch turned off. Im not trying to turn on or run my pump currently, doing that in the power off position

 

[JamesW]

Probably a bad switch.

Show the pump and switch.

 

[TinFoilHat]

What is turning on and providing power to the pump?

 

[Giant655]

I guess a regular outdoor on/off switch?
Pics attached of the switch, pump, pump info, capacitor and top of it

 

[MSchutzer]

If the motor is getting hot then it’s getting voltage, the the loud hum of the stalled rotor is also a clue that it’s getting power.

How is it humming and getting hot if you are testing with the power off, I’m missing something?

 

[Giant655]

If the motor is getting hot then it’s getting voltage, the the loud hum of the stalled rotor is also a clue that it’s getting power.

How is it humming and getting hot if you are testing with the power off, I’m missing something?

That's what I'm trying to get at lol. I just happened to catch it in passing today. The pump hasn't been touched all winter. Today I was out cutting grass and walking past I heard the motor hum and click as if I turned the power on and the capacitor was bad. The power is off, not at the breaker but the main on/off switch for the pump. I removed the capacitor out of sheer curiosity. So now the switch is still off, there's no capacitor installed on the pump, and the pump is still making noise

 

[JamesW]

Maybe the switch is bad and not turning off?

You will need to check that if you are comfortable with electricity.

Try rotating the shaft from the back.

Pop off the back shaft cover and try to spin the shaft.

The shaft cover is a small round disc at the back center that can be popped off with a screwdriver.

Try a new capacitor.

 

[JamesW]

I removed the capacitor out of sheer curiosity.

You removed it with the motor making noise?

 

[JamesW]

 

[Giant655]

Maybe the switch is bad and not turning off?

You will need to check that if you are comfortable with electricity.

Try rotating the shaft from the back.

Pop off the back shaft cover and try to spin the shaft.

The shaft cover is a small round disc at the back center that can be popped off with a screwdriver.

Try a new capacitor.

Able to spin the motor, it was nasty at first but freed up after rotating a bit. Yes I took the capacitor off with that noise. I used thick rubber gloves and made sure to handle what I was doing with the tact of someone who understands why and how capacitors are dangerous.

 

[TinFoilHat]

You should be starting with your power switch that seems to have failed.

 

[MSchutzer]

If the motor acted like the rotor was locked in place before you freed it up the capacitor “may” be okay. A open capacitor or a locked rotor will sound the same. When the cap is bad, or if the rotor is locked, then the motor will get hot, overheat, and then the internal thermal cutout will open the power to the motor. When the motor cools down enough the thermal cutout resets and the cycle repeats.

It sounds like you also have a bad on/off switch.

Turn the breaker for the motor off, reinstall the cap, and then turn the breaker back on. Power it up and see if it runs. Still likely a bad cap, but if the rotor was locked up that could also be the cause.

 

[Lake Placid]

Check the actual switches under the cover plate. Those outdoor switch covers have a tendency to fail and not move far enough to force the switch into the off position. Seals fail and let water into what should be a sealed box….Inspect everything related to the switch box.

On another note, that motor housing looks well used and beyond its useful life. It’s missing its back cover plate in addition to the maladies you describe. There’s corrosion on the bottom mounting foot indicative of shaft seal failure. I can’t tell if the wet end is useful or in a state of degradation from the pics…Perhaps it’s time to consider moving on and upgrading.

 

[ol_whistle_britches]

Lots of good stuff here. I’d love to see the resolution of this matter out of curiosity, but personally I would order a new pump. 24 years out of a motor is a life well lived. And switchgear too, for reasons others have stated.

Given the age and the way you described the shaft turning, I’m still not convinced it’s just a cap. It makes sense that the cap may have failed in addition to whatever else is going on. If it was just a failed cap I expect it would have spun up when you started rotating the shaft.

it was nasty at first but freed up after rotating a bit.

Please describe further. Sticky? Grinding? Stiff?

My mind is still leaning towards the wet end. I’ll add debris stuck in impeller to my original bets (winding short and/or impeller failure).

Kindly tear the whole pump down so that we can all sleep soundly knowing what really happened. The suspense is killing me.

 

[Lake Placid]

it was nasty at first but freed up after rotating a bit.

Please describe further. Sticky? Grinding? Stiff?

This is typical when a shaft seal is leaking and the pump is winterized and allowed to dry out. Corrosion will set in and the pump won’t spin up until manually freed up by spinning it with a wrench etc.