Aerator pump issues ....?

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brantmacga

brantmacga

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Georgia
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Former Child
Need some help sorting this out.

Customer has three of these aerator pumps; I went a couple of weeks ago to check out an issue; one worked fine, one was rotor locked, the other was pumping very weak and pulling about 22A and after a minute would trip the 15/2 breaker (pump rated at 6A).

Told the customer he needed to replace one pump for sure and to check and make sure there was nothing obstructing the inlet of the 3rd pump.

Went back Friday and the customer had pulled the apparatus out of the water and replaced the two pumps having issues. I verified by turning power on to the two that had issues that he had replaced the correct pumps. I then pulled the new wiring into the panel for him to drop back in the water later.

He put them back in the water this weekend, and now the pump that was working has issues.

It will pump very weakly for about 5 seconds, then stop pumping for about 30 seconds, then start again. It pulls 17A while pumping, and 5A while not pumping.

I called the manufacturer tech support, and they said “let us just send you a new pump.”

So my question is, do these things need to be primed somehow? I know literally nothing about them. But it seems like we’re just doing something wrong on getting it to work correctly seeing as how it was fine before pulling it out of the water. The customer was not home today and had already pulled the boat out of the water so i couldn’t go out and see if anything was obstructing it.

Here’s a video I took.... let’s see if this link works... https://share.icloud.com/photos/0wT-H3zZ0iRlURy3fppzOXOkQ#Quitman




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brantmacga said:
Need some help sorting this out.

Customer has three of these aerator pumps; I went a couple of weeks ago to check out an issue; one worked fine, one was rotor locked, the other was pumping very weak and pulling about 22A and after a minute would trip the 15/2 breaker (pump rated at 6A).

Told the customer he needed to replace one pump for sure and to check and make sure there was nothing obstructing the inlet of the 3rd pump.

Went back Friday and the customer had pulled the apparatus out of the water and replaced the two pumps having issues. I verified by turning power on to the two that had issues that he had replaced the correct pumps. I then pulled the new wiring into the panel for him to drop back in the water later.

He put them back in the water this weekend, and now the pump that was working has issues.

It will pump very weakly for about 5 seconds, then stop pumping for about 30 seconds, then start again. It pulls 17A while pumping, and 5A while not pumping.

I called the manufacturer tech support, and they said “let us just send you a new pump.”

So my question is, do these things need to be primed somehow? I know literally nothing about them. But it seems like we’re just doing something wrong on getting it to work correctly seeing as how it was fine before pulling it out of the water. The customer was not home today and had already pulled the boat out of the water so i couldn’t go out and see if anything was obstructing it.

Here’s a video I took.... let’s see if this link works... https://share.icloud.com/photos/0wT-H3zZ0iRlURy3fppzOXOkQ#Quitman




Sent from my iPhone using Tapatalk
Click to expand...

Do you have a cut sheet or make and model on the pumps?
 
12afc629f2d6785849e3d4945250901f.jpg



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Well, I checked out their web site and they don't provide much info beyond a spec, pump curve, and limited construction data.

I'm a "city boy" and not familiar with aerators as a service. Can you give a description for those of us who have led a sheltered existence?
 
gadfly56 said:
Well, I checked out their web site and they don't provide much info beyond a spec, pump curve, and limited construction data.

I'm a "city boy" and not familiar with aerators as a service. Can you give a description for those of us who have led a sheltered existence?
Click to expand...

I agree that website is not very detailed. Based on his mention of a boat, I'd say these are for a pond. They are meant to help treat the water and eliminate dissolved gases.

I have worked with water treatment using deaerators (used to pull air out of the water in order to force solids to the bottom of a tank) but from what i can tell no priming should be required with these aerators. To me they are no different than the small submersible sump pumps one would use to drain a swimming pool
 
First off that's the COMPLETELY wrong pump for this application. That's a submersible dewatering pump for pumping out manholes and such, not at all a pond aerator!

Somebody was being cheap here and this is what they get. Problems.

Otterbine is probably the most common manufacturer of pond aerators and fountains. There are others though and but all will be more than your customer paid for that pump. As far as I know they all float so they don't pick up crap from the bottom and are tethered to shore on two sides.

https://www.otterbine.com/aerators-fountains/aerating-fountains/

-Hal
 
Email Stancor and ask if these pumps have duty cycle spec.
 
No need.
The motor shall be capable of operating continuously, submerged in liquid of 40oC (104 oF) without overheating. The motor shall be capable of handling up to 10 evenly spaced starts per hour.
Click to expand...

Interesting note under "Warning" on the label in the picture:

2) Risk of electric shock. This pump has not been investigated for use in swimming pools or marine areas.
Click to expand...

So I would interpret that to mean that it isn't designed for permanent use in ponds or swimming pools because of an electrocution hazard to anybody in the water.

-Hal
 
when we are aerating in aquaponics, we use air pumps through air stones in the tanks. This sounds more like the guy is running his filtering instead... but back when i used to fish out of Point Pleasant, NJ, I never recalled seeing any fishermen trying to filter baitboxes or live wells... because they claimed it was easier to drain and clean out daily than to install and replace pumps... through filters...
Remember my uncle, an avid saltwater and freshwater aquarium owner, talking to the boat captain for hours over the pluses and minuses of various filtering arrangements for aquariums. Shame I was 13 and not that interested in doing anything but catching blues and fluke..lol

But what kind of aerator system do you need for pumping? if it is for filtering, you need dirty water pumps rather than house pumps, but you find many at the boat supply houses that are dc, or ac.. depending upon the applications. Even solar equipped..
 
What's that SA US mark mean? Does it even have a proper listing?

I also agree with the others, these don't appear to be proper aerator pumps, but instead pumps made to pump out manholes, vaults, basins, etc.

More flow=more amps.
 
Cow said:
What's that SA US mark mean? Does it even have a proper listing?

I also agree with the others, these don't appear to be proper aerator pumps, but instead pumps made to pump out manholes, vaults, basins, etc.

More flow=more amps.
Click to expand...

The photo shows a CSA trademark with a C, & US listing.
 
Pumps are about 30” under surface of water; they’re attached to what is about a 30” diameter buoy, and each pump has a 2” pipe coming up through that buoy. It also has lights on top. Idk who manufactured the complete system I just know it was built and sold to the owner for this specific purpose.


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I see Stancor pumps used all the time to aerate settling ponds at aggregate plants (to improve water quality before discharge). They use them as dewatering pumps elsewhere so they just have the same pumps doing the aeration. I don’t see a problem with their use.

But I agree it might be that they are overloading them if the discharge is too wide open, ie not enough head. Often times someone will build something like this and throttle the output, then someone unfamiliar with how pumps work comes along later and wants “more power” (insert Tim Allen grunting sound) and opens up or removes the throttling mechanism. It’s easy enough to check though, just run a pump and measure the current. If the motor is overloading, the current will be above the FLA.

Looking back at your first post, you already did this. 6A FLA, pulling 17A when pumping = Overloaded. These are centrifugal pumps so if the inlet was blocked, there is no flow so no load on the pump. The only way you can overload a centrifugal pump is by having TOO MUCH flow (or a seized bearing or other mechanical issue). I’d venture to say someone modified the output piping and they have been overloading these pumps for a long time but being submersible, they got away with it because of the water keeping them cool. These are thermally protected pumps, which explains it working for a while, shutting down, then restarting. That’s exactly what would happen when the Klixon thermal switch in the pump over heats and opens, then cools down and resets.
 
I can tell from experience on a commercial 7.5 HP pool pump I replaced about 20 years, it burned out after a few days. The pump was "running away" and drawing too many amps. Buy restricting the discharge with a butterfly valve it solved the amp issue, but cut the flow rate thus not meeting the code requirement for the proper turnover rate.
By suggestion of the pump manufacturer, I swapped a provided impeller from a 5 HP pump which solved the problem.

Sounds like this pump is "running away" also and burning out.
 
Jraef said:
Looking back at your first post, you already did this. 6A FLA, pulling 17A when pumping = Overloaded. These are centrifugal pumps so if the inlet was blocked, there is no flow so no load on the pump. The only way you can overload a centrifugal pump is by having TOO MUCH flow (or a seized bearing or other mechanical issue). I’d venture to say someone modified the output piping and they have been overloading these pumps for a long time but being submersible, they got away with it because of the water keeping them cool. These are thermally protected pumps, which explains it working for a while, shutting down, then restarting. That’s exactly what would happen when the Klixon thermal switch in the pump over heats and opens, then cools down and resets.
Click to expand...

What's on the end of that 2" pipe that goes up through the buoy where the water shoots out? How long have they been having this problem?

-Hal
 
Jraef said:
I see Stancor pumps used all the time to aerate settling ponds at aggregate plants (to improve water quality before discharge). They use them as dewatering pumps elsewhere so they just have the same pumps doing the aeration. I don’t see a problem with their use.

But I agree it might be that they are overloading them if the discharge is too wide open, ie not enough head. Often times someone will build something like this and throttle the output, then someone unfamiliar with how pumps work comes along later and wants “more power” (insert Tim Allen grunting sound) and opens up or removes the throttling mechanism. It’s easy enough to check though, just run a pump and measure the current. If the motor is overloading, the current will be above the FLA.

Looking back at your first post, you already did this. 6A FLA, pulling 17A when pumping = Overloaded. These are centrifugal pumps so if the inlet was blocked, there is no flow so no load on the pump. The only way you can overload a centrifugal pump is by having TOO MUCH flow (or a seized bearing or other mechanical issue). I’d venture to say someone modified the output piping and they have been overloading these pumps for a long time but being submersible, they got away with it because of the water keeping them cool. These are thermally protected pumps, which explains it working for a while, shutting down, then restarting. That’s exactly what would happen when the Klixon thermal switch in the pump over heats and opens, then cools down and resets.
Click to expand...

Jraef, this is very well stated. For people who have not worked around pumps however this one simple thing can " seem " counter intuitive until its explained.
Forward curved centrifugal fans are the exact same scenario, with the older style VAV systems having a set of dampers on the discharge side of the fan that modulate down on rise of main duct static pressure. We have some 1 HP cart pumps that get run for CIP duty that are run on the edge all the time. There is a TEE fitting on the discharge where the guys can open to 2 ports at the same time which will overload and overheat those rigs pretty fast, but the motors somehow seem to take it for quite a while. Opening to those 2 ports is running in Free Water as you put it with little to no back pressure. A butterfly valve on the discharge outlet can be quite useful.
 
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