How to open submersible pump to look at impellors?


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Old 03-22-08, 10:49 AM
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How to open submersible pump to look at impellors?

Thanks in advance for your patience if this is a dumb question... but so far I can't find how to do this

While I'm waiting to figure out whether an all-stainless-steel pump vs. a nylon/stainless steel pump is better for a sandy situation, I thought I'd take my pulled submersible apart to see how it's all put together.

I found the schematic for it on the Aermotor web site (it's an 1/2 HP Aermotor T8-50) and so far I've got the cable guide off, and have separated the bottom motor from the top pump part.

It looks as if the motor has overheated, if my assumption that the deep dark discoloration on the motor sheath is indicative of an overheated motor is correct (am I correct in this assumption?).

I appears from the schematic that the top and bottom black nylon parts threaded, and simply screw off? If so, how in heck do I get them off--I can't seem to get a strong enough grip on it to twist either end off. Should I put it in a vise and use a big wrench and yank?

eeek. Well, it doesn't work anyway, so I guess I can't get any worse off than I already am, but if the pump part is salvageable I don't want to mess it up--but I thought I should have a look at the impellers to see if they are either damaged or clogged (check valve works, no holes in droppipe, as water in drop pipe did not fall as pump was raised).

Any hints on how to do this?
Again, thanks for your patience if this is a dumb question...
-Alyce
 
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Old 03-22-08, 11:49 AM
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most likely the use of an impact gun with a "pop" "pop" "pop" action on your part.

just be sure of the threads being left or right hand. Quite often the threads are designed so as the pump runs, the nut would be tightened rather than loosened.

and to the overheated motor; these pumps are designed to be totally submerged. The water does provide cooling, If the pump is not set deep enough to completely submerge the thing, this could cause overheating.
 
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Old 03-22-08, 12:28 PM
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Wow! Thanks for your quick reply!

Fortunately, I do have a hammer gun, but not sure as to how to attach it to the top or bottom?

The pump was completely submerged in water--it was about 10 feet below the average ground water level.

I am thinking that sand/sediment or something did something to the impellers to prevent them from turning and pushing water up the droppipe, making the motor overheat.

The symptoms of the well pump before pulling were:
humming noise and vibration on the droppipe, but no water coming up--zero pressure at the pump pressure switch/gauge. No leak in the droppipe, as when the droppipe was lifted 5 feet and left there for a week the water in the droppipe never fell down.

Control box capacitor was replaced, voltmeter readings were OK for power to the pump motor, but still no water coming up the pipe. So, we pulled the pump. A bunch of sand was in the top of the pump when it came up, a bunch of grey gook was in the small area between the pump and the motor when I took them apart. The screen was not clogged. The driveshaft from the motor spins freely--the cogs in the driveshaft are not worn. The cogs in the female part of the pump where the driveshaft fits are not worn, but it does wiggle a bit. There is still water inside the pump part--the check valve is intact I believe (although I don't know how to check if is allowing water UP, but it did prevent water from flowing back DOWN while it was in the well.

Is there any way to test the motor without a load?
-Alyce
 
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Old 03-22-08, 12:48 PM
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Is there any way to test the motor without a load?
you can simply hook it up to the controller and turn it on. Of course this will not simulate a load, which may cause a problem that cannot be determined without a load.

I have run across a few pumps that have done similar things. I used a very large capacitor (commonly referred to as a "hard start kit" for an A/C unit) to give the pump one serious kick in the pants. That got it going and all has been fine for a couple years now. I suspect there was simply sand preventing the impeller from rotating. The extra kick broke it free and has not happened again.

if the pump was not turning at all, you should have tripped whatever overload there is in the system. A motor not turning will draw a LOT of current.

A bunch of sand was in the top of the pump when it came up
Not good. It could have seized the pump, at least temporarily OR it could have worn the impellers or housing enough so it could not pump water.

a bunch of grey gook was in the small area between the pump and the motor when I took them apart.
grease maybe and meant to be there? Maybe worn metal mixed with something else? Not sure.

check valve does not affect water going up, at least as long as it is allowing water into the pump. Its sole purpose is to retain water in the pump and riser pipe.

as to disassembly of the pump;

if you have a drawing, that should clue you as to what comes off and what doesn't. A bit of close inspection and comparison generally will show you the way.

look for washers that are bent over to prevent nut rotation. Pins of any sort to do the same.
 
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Old 03-22-08, 01:13 PM
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>> A bunch of sand was in the top of the pump when it came up
>Not good. It could have seized the pump, at least temporarily >OR it could have worn the impellers or housing enough so it >could not pump water.

Would sand seizing the pump cause the original control box capacitor to degrade/leak/fail? No circuit box fuses were flipped--only the original capacitor drained out over the relay. (We cleaned the relay, put in a new capacitor, tested the electric on it, voltmeter showed OK, hooked it up to the pump, no start, disconnected and then pulled the pump.)

Sand at the top of the pump (outside the droppipe--resting on the top) is why I want to open the pump and look at the impellers, to see if they are clogged, seized, or if a lot of sand is inside.

The pump was at 84 feet down the well, at least 10 feet below water table. Very sandy soil here; casing is down into the water.

Question: My neighbor has been running a commeriial sized grader (very heavy equipment--he's a rock/sand/etc. construction supplier) every day for about 30 days now, grading his huge lot. The grader made multiple sweeps within 20 to 30 feet of my well. Would this cause sufficient vibration deep in the well to stir up enough sand/sediment to seize the pump?

If so, I'd like to know, because I've asked him several times to cool it with the grading (because it sets up a sympathetic vibration in my rock wall home so the noise is louder inside than outside! not to mention the horrendous vibration inside the house...). Knowing it also is messing up the well and seizing the pump would give me bonus points I hope in my communication with him As far as I can tell, he's just running the grader for practice or training an employee.

Another question: given that it's sandy soil here anyway, is there a type or brand of submersible that you know of that is especially good at handling sandy wells? All I know is what I've pulled up out of the well -- and since it appears that everything has failed, from capacitor to motor to impellers, and I have to replace everything anyway, I'd rather replace it with something attenuated to the actual circumstance of the well.

Many thanks in advance!
-Alyce
 
 

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