Drive unit for pump burned up after disconnecting spa valve, what did I do wrong?

[platon20]

OK so my spa valve was not working, so I disconnected the motor/drive on top so I could at least turn the spa valve by hand.

After doing this, I ran the spa for about 2 hours with no problems at all.

Then I manually turned the valve back to the pool setting and restarted the pump.

Everything ran fine for at least an hour. No strange sounds, no burning smells, no smoke.

I went to bed at 11 PM and when I woke up at 7 AM, the pump was off (it's supposed to run 8 PM to 8 AM) so I knew something was wrong.

The control screen on the pump was completely blank -- zero LEDs lit up. All the other electronics were fine.
I opened up the pump drive unit, and there's a pic below of what I found -- apparently there was some kind of fault/short circuit because the black/ground wire post was completely melted and it smelled terrible.

Here's the thing though -- there was no water inside the drive unit, it was completely dry.

So the only thing I can figure is that I did something when I disconnected the spa valve that caused a short circuit to the pump.
But this doesnt really make sense either, because all the other electronics are fine, the panel works fine, the chlorinator works fine, heater works fine.
Also there were no circuit breakers tripped.

My specific questions are these:
1. Did disconnecting the spa valve cause the pump drive to burn out or was this just coincidence?
2. Can I just replace the drive unit or do I need to replace the entire pump?
3. When I install a new drive/pump, what is to stop it from shorting out again? I dont want to waste a thousand dollars if it's just going to happen again.
4. Why didnt any circuit breakers trip?

 

[Jimrahbe]

20,

I don't think manually moving the spa valve had anything to do with that issue...

I suspect that your pump is pretty old.. If 10 or more years old, I'd replace the whole thing.

Thanks,

Jim R.

 

[proavia]

There are 2 valves that control water from and to the spa.
There is a suction side and return side valve. If you only moved the return side valve manually and the other valve stayed in the spa position, chances are that you sucked all the water out of the spa and returned it to the pool. This would have caused the pump to run dry, overheat and possibly malfunction.

 

[platon20]

I thought about that but the spa was completely full when this happened and never emptied. The configuration was set to run on the pool side the entire night.

 

[ajw22]

Who installed that pump?

That burnt wiring was a long time in developing due to loose wire connections developing corrosion, resistance, and heat until the final end.

It was coincidence the ending came just after you worked on the valve.

 

[platon20]

Who installed that pump?

That burnt wiring was a long time in developing due to loose wire connections developing corrosion, resistance, and heat until the final end.

It was coincidence the ending came just after you worked on the valve.

The pool company did it, but I loosened the wires so the picture was more clear. There was a plastic post sitting there that was completely burned out from the short. I just removed it to clear up the photo better.

It's very possible the connections were loose or it was not installed right, I just think it's weird that it burned out around the time I removed the spa valve controller.

 

[ajw22]

I just think it's weird that it burned out around the time I removed the spa valve controller.

Gremlins.

 

[platon20]

Update: I replaced the drive unit yesterday and so far after 24 hours the pump is running fine.
Hopefully it stays working well.

Next task is to replace one of the globrite LEDs. Good grief those things are freaking expensive at $500 a pop!

I've had the pool since 2018, so I guess this is about the right duration they last?

 

[bradgray]

Electricians tend to try and tighten the wires on one side only, as if it has two 'slots' similar to the relay terminals. However, the retainer rotates and tilts heavily when you tighten, unlike the relays.

This leads to poor contact and opportunity for arcing. I'm not necessarily confirming this is why yours failed, but it IS one of the two most common reasons we see drive failures like yours.

We never, ever leave them on one side. We remove the screw entirely, and curl the wire around the screw like you would a typical outlet or switch terminal in a home. This ensures the retainer is in contact with the wire under at least 3 sides and doesn't get tweaked. You should also never use a drill, as it strips the threads.

I would reopen the drive and redo the connections this way to help prevent it from recurring.