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Old 03-30-2008, 02:31 AM   #1
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Troubleshooting a septic pump


Troubleshooting a septic pump (less than 2 yrs old) in the backyard- would run for a period of time then trip the breaker in the house. Existing wiring is UF 12-2 directly buried in the ground with no GFI. I tried bypassing the underground wiring by running an extension cord from the pump to a GFI outlet in the garage. It ran for a while then tripped the GFI. The GFI would not reset unless I unplugged the pump. The pump has a piggyback style plug, one for the float and one for the motor I'm assuming. I can plug in one or the other without tripping the GFI but as soon as I plug in both together, the GFI trips. Any ideas on why it does that? I can come back the next day and it'll reset (breaker in the past, GFI now) fine so I'm wondering if the float switch is the problem. My thinking is that when the water level gets down to a certain point, the float switch trips the breaker/GFI and won't let me reset it until the water level rises.

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Last edited by Dustball; 03-30-2008 at 02:40 AM.
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Old 03-30-2008, 07:23 AM   #2
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Troubleshooting a septic pump


I will assume that the motor is single phase...the voltage is irrelevant.

Usually, the float switch will simply "open" or "close" the active (hot) conductor. I cannot see how a faulty float switch would cause your problem.

It is typical for motors to have a decreased insulation resistance as they get hotter (& older). A decreased insulation resistance will mean an increase in leakage current to earth, which could trip an Earth Leakage Protection Device. If the GFI is a 30mA device, it means that there is somewhere between 15mA & 30mA leakage current, which means that the motor/cables is in poor shape.

Have the insulation resistance of the motor tested by someone who knows how to do this test properly. If the result is above 10 megohms, the motor is ok in which case, the insulation of the supply cables may be faulty. If the result is less than 10 megohms, there may be a problem with the motor &/or supply cables. If the result is 1 megohm or less, the motor is dangerous & must be repaired/replaced immediately.

Insulation resistance tests should only be done on motors when they are hot. A "cold" test will give incorrect results.
It may also be wise to test the insulation resistance of all the cables (supply & float switch).

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Last edited by elkangorito; 03-30-2008 at 08:54 AM. Reason: Additional info
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Old 03-30-2008, 10:08 AM   #3
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Troubleshooting a septic pump


Shut the power, uncouple the union, and pull the pump up and check the impeller for a pebble or some other crap.
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Old 03-30-2008, 10:42 AM   #4
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Troubleshooting a septic pump


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Originally Posted by James Con View Post
Shut the power, uncouple the union, and pull the pump up and check the impeller for a pebble or some other crap.
Was that a PUN? He did say it was a septic tank...
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Old 03-30-2008, 01:35 PM   #5
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Troubleshooting a septic pump


It's possible that the cord was damaged, most likely where it enters the motor. If the pump was lowered into the tank by the cord, this is even more likely.

The reason it trips the breaker/GFI intermittently is because it's in the process of failing. Also, moving the cord, even slightly will affect the damaged part. As stated above, a megger test will confirm where the problem is.

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Old 03-30-2008, 02:50 PM   #6
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Troubleshooting a septic pump


Reset the GFI today and the pump ran for 15 mins before the GFI tripped again. Seems that it has to be left alone for 15+ hours before the pump will allow the GFI to reset. I'll see about getting access to inside the tank as it's way too muddy to be walking around out there and it looks like we're expecting 6+ inches of snow tomorrow.
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Old 03-30-2008, 07:54 PM   #7
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Troubleshooting a septic pump


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Originally Posted by chris75 View Post
Was that a PUN? He did say it was a septic tank...
If the pump is bound up it will trip.(Common) Ya have the pump and then off the pump comes about a four foot pipe that 90's into the field just after the 90 there is a union ( coupling) undo the coupling undo the wiring and pull the pump and the four foot pipe up. there should be a rope on the pump if not be careful pulling it up by the wire and pipe. Unscrew the bottom plate and check the impeller to see if it's bound or something jammed in it. Maybe some corn lol. If so clear the jam and test it. If you don't feel comfortable testing it take it to a plumbing supply house sometimes they have a fiftyfive gallon drum of water to test them. If bad replace it. Usually the contacts where the power or the floats plug into the housing corrodes so replacing the power cord or float cord is useless. That happens due to improper float adjustment. The pump should always be submersed completly. This prolongs the corrosion, no air contact with the pump. They should last longer than two years unless you have run off water constantly filling your tank. Just replace it. Get a meyers usually a model ME 40 will do the trick unless your pumping far up hill. They are good and the warranty is a year.
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Old 03-31-2008, 02:59 AM   #8
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Troubleshooting a septic pump


Quote:
Originally Posted by James Con View Post
Shut the power, uncouple the union, and pull the pump up and check the impeller for a pebble or some other crap.
Quote:
Originally Posted by James Con View Post
If the pump is bound up it will trip.(Common) Ya have the pump and then off the pump comes about a four foot pipe that 90's into the field just after the 90 there is a union ( coupling) undo the coupling undo the wiring and pull the pump and the four foot pipe up. there should be a rope on the pump if not be careful pulling it up by the wire and pipe. Unscrew the bottom plate and check the impeller to see if it's bound or something jammed in it. Maybe some corn lol. If so clear the jam and test it. If you don't feel comfortable testing it take it to a plumbing supply house sometimes they have a fiftyfive gallon drum of water to test them. If bad replace it. Usually the contacts where the power or the floats plug into the housing corrodes so replacing the power cord or float cord is useless. That happens due to improper float adjustment. The pump should always be submersed completly. This prolongs the corrosion, no air contact with the pump. They should last longer than two years unless you have run off water constantly filling your tank. Just replace it. Get a meyers usually a model ME 40 will do the trick unless your pumping far up hill. They are good and the warranty is a year.
Unless I am mistaken, a GFI does not trip on an overload (it only detects earth leakage current). Earth leakage current is related to voltage & is therefore directly proportional to the applied voltage across the winding conductors. An increased current going through the winding conductors will not constitute an increase in earth leakage current.

Quote:
Originally Posted by Dustball View Post
Reset the GFI today and the pump ran for 15 mins before the GFI tripped again. Seems that it has to be left alone for 15+ hours before the pump will allow the GFI to reset. I'll see about getting access to inside the tank as it's way too muddy to be walking around out there and it looks like we're expecting 6+ inches of snow tomorrow.
This is typical of a motor with too much leakage current. When cold, it has an acceptable insulation resistance. When hot, it does not thus the 15+ hours to "cool off".
Incidentally, you can't "test" a motor by sticking it in a water tank. It can only be tested by electrical personnel who possess the correct knowledge & equipment. In order to prevent any further time wastage, I recommend to simply have an insulation resistance test done. I'll bet my left knacker that the motor fails the test (when it is hot). I don't think you have any other problems apart from this.
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Old 03-31-2008, 05:01 AM   #9
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Troubleshooting a septic pump


Quote:
Originally Posted by elkangorito View Post
Unless I am mistaken, a GFI does not trip on an overload (it only detects earth leakage current). Earth leakage current is related to voltage & is therefore directly proportional to the applied voltage across the winding conductors. An increased current going through the winding conductors will not constitute an increase in earth leakage current.



This is typical of a motor with too much leakage current. When cold, it has an acceptable insulation resistance. When hot, it does not thus the 15+ hours to "cool off".
Incidentally, you can't "test" a motor by sticking it in a water tank. It can only be tested by electrical personnel who possess the correct knowledge & equipment. In order to prevent any further time wastage, I recommend to simply have an insulation resistance test done. I'll bet my left knacker that the motor fails the test (when it is hot). I don't think you have any other problems apart from this.
And then what? get a hundred dollar motor rewound. And what motor shop in there right mind is gonna put a septic pump on there work bench??????? And the original problem was a tripped breaker(Locked Rotor)Just replace the pump. Also the plugs should be cut off the pump and all the connections in the tank should be in a watertight box mounted to the pipe coming off the pump as high as possible. Your gonna need watertight compression fittings to screw into the watertight box for the pump power,Float,Alarm x2 and line in. Total of five. two round for motor wires and three for romex. If you want to replace the whips coming off the pump you can they are replaceable but chances are the internal contacts that the whips plug into are corroded they will break off. If you want diagrahms of the proper setup in the tank let me know I could get them to you. Now might be a good time to get pumped out and redo the wiring right.

Last edited by James Con; 03-31-2008 at 09:41 AM.
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Old 03-31-2008, 09:45 AM   #10
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Troubleshooting a septic pump


Quote:
Originally Posted by elkangorito View Post
Unless I am mistaken, a GFI does not trip on an overload (it only detects earth leakage current). Earth leakage current is related to voltage & is therefore directly proportional to the applied voltage across the winding conductors. An increased current going through the winding conductors will not constitute an increase in earth leakage current.



This is typical of a motor with too much leakage current. When cold, it has an acceptable insulation resistance. When hot, it does not thus the 15+ hours to "cool off".
Incidentally, you can't "test" a motor by sticking it in a water tank. It can only be tested by electrical personnel who possess the correct knowledge & equipment. In order to prevent any further time wastage, I recommend to simply have an insulation resistance test done. I'll bet my left knacker that the motor fails the test (when it is hot). I don't think you have any other problems apart from this.
Being these motors are filled with transformer oil can you still do an insulation resistance test. FMinfo thanks
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Old 04-01-2008, 11:33 AM   #11
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Troubleshooting a septic pump


Quote:
Originally Posted by James Con View Post
And then what? get a hundred dollar motor rewound. And what motor shop in there right mind is gonna put a septic pump on there work bench??????? And the original problem was a tripped breaker(Locked Rotor)Just replace the pump. Also the plugs should be cut off the pump and all the connections in the tank should be in a watertight box mounted to the pipe coming off the pump as high as possible. Your gonna need watertight compression fittings to screw into the watertight box for the pump power,Float,Alarm x2 and line in. Total of five. two round for motor wires and three for romex. If you want to replace the whips coming off the pump you can they are replaceable but chances are the internal contacts that the whips plug into are corroded they will break off. If you want diagrahms of the proper setup in the tank let me know I could get them to you. Now might be a good time to get pumped out and redo the wiring right.
Quote:
Originally Posted by James Con View Post
Being these motors are filled with transformer oil can you still do an insulation resistance test. FMinfo thanks
You obviously didn't listen to or did not understand a word that I said.

First, let's deal with this "transformer oil" issue. Motors do not contain transformer oil. Why? Well, it isn't called "transformer oil" for nothing. The other reason is that this oil does have a high affinity for water & it will also degrade the performance of the motor (viscosity).

Let's deal with the "And then what? get a hundred dollar motor rewound. And what motor shop in there right mind is gonna put a septic pump on there work bench???????", problem.

Firstly, I never ever mentioned a rewind. It is obviously uneconomical for a motor of a small size. Secondly, a "motor shop" is not required to test such a motor. It can be tested in situ by a competent electrician with the appropriate equipment. This very easy, inexpensive & simple test will/could eliminate such other problems as degraded cable/switchgear insulation resistance.

If you think that a GFI trips because of "overcurrent", you may like to research how a GFI operates. Let me give you a hint & as I said before, unless I'm mistaken, a GFI DOES NOT detect overcurrent. It only detects "earth leakage" current. If you don't know the difference between these 2 types of currents, you have no business posting here.


EDIT.
Transformer oil is an excellent insulator & therefore can withstand normal insulation tests.
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Last edited by elkangorito; 04-01-2008 at 12:21 PM. Reason: Added info
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Old 04-01-2008, 08:40 PM   #12
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Troubleshooting a septic pump


Let's not forget what forum you are on DIYCHATROOM. Everyone always wants to have a pissing contest and prove ther background. Don't forget DIY. So to explain all your BS to a DIYER, Useless. Get to the basics. There is no GFCI in his original problem. Why don't you go read again. He compounded the problem. Again tripped breaker locked rotor I'll bet my right ball on that. Also do a little research these motors are filled with transformer oil, readthis Page 7 # 12 http://www.femyers.com/pdf/pdf.sse/s.../23833a245.pdf
Throw another shrimp on the barbi and do a little research on these motors they will sit with a locked rotor for a while due to the cooling of the oil and water it is submerged in. I'll say again replace the pump. Before your local sewage enforcment officer finds out from a neighbor due to the smell in the air. I am an SEO for a town in Pa. and I have made people get ther tanks pumped every day until the problem gets fixed. You are looking at alot of money, 200 to 300 dollars for a 1000 gallon tank. Change the pump.

Last edited by James Con; 04-01-2008 at 08:47 PM. Reason: page #
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Old 04-02-2008, 12:51 PM   #13
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Troubleshooting a septic pump


For the time being, the pump is being run manually bypassing the float. The pump runs fine without tripping the GFI. The pump is plugged in until it's all the way to the point where there is no more water then it's unplugged. Accessing the pump and float will have to wait until the ground firms up.
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Old 04-02-2008, 01:45 PM   #14
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Troubleshooting a septic pump


Quote:
Originally Posted by Dustball View Post
Troubleshooting a septic pump (less than 2 yrs old) in the backyard- would run for a period of time then trip the breaker in the house. Existing wiring is UF 12-2 directly buried in the ground with no GFI. I tried bypassing the underground wiring by running an extension cord from the pump to a GFI outlet in the garage. It ran for a while then tripped the GFI. The GFI would not reset unless I unplugged the pump. The pump has a piggyback style plug, one for the float and one for the motor I'm assuming. I can plug in one or the other without tripping the GFI but as soon as I plug in both together, the GFI trips. Any ideas on why it does that? I can come back the next day and it'll reset (breaker in the past, GFI now) fine so I'm wondering if the float switch is the problem. My thinking is that when the water level gets down to a certain point, the float switch trips the breaker/GFI and won't let me reset it until the water level rises.
Quote:
Originally Posted by Dustball View Post
Reset the GFI today and the pump ran for 15 mins before the GFI tripped again. Seems that it has to be left alone for 15+ hours before the pump will allow the GFI to reset. I'll see about getting access to inside the tank as it's way too muddy to be walking around out there and it looks like we're expecting 6+ inches of snow tomorrow.
Quote:
Originally Posted by James Con View Post
Let's not forget what forum you are on DIYCHATROOM. Everyone always wants to have a pissing contest and prove ther background. Don't forget DIY. So to explain all your BS to a DIYER, Useless. Get to the basics. There is no GFCI in his original problem. Why don't you go read again. He compounded the problem. Again tripped breaker locked rotor I'll bet my right ball on that. Also do a little research these motors are filled with transformer oil, readthis Page 7 # 12 http://www.femyers.com/pdf/pdf.sse/s.../23833a245.pdf
Throw another shrimp on the barbi and do a little research on these motors they will sit with a locked rotor for a while due to the cooling of the oil and water it is submerged in. I'll say again replace the pump. Before your local sewage enforcment officer finds out from a neighbor due to the smell in the air. I am an SEO for a town in Pa. and I have made people get ther tanks pumped every day until the problem gets fixed. You are looking at alot of money, 200 to 300 dollars for a 1000 gallon tank. Change the pump.
There is no GFCI in his original problem. Really? Check the above bolded parts.

Also, your "oil filled" motor is not a good thing, as I suggested. It is simply a "cheap & nasty" way of doing things. See the below links.

http://tristate.apogee.net/mnd/mfnrins.asp

http://ecmweb.com/mag/electric_hot_issue_motor/

http://www.maintenanceresources.com/...al/helping.htm

http://www.weilaquatronics.com/htm/g...w_august99.htm

The oiled filled motor you cite is a "shaded pole" motor, which is usually used for such loads as room fans. Most "decent quality" submersible pump motors are NOT of this type. They are standard induction motors, which are NOT oil filled.

Quote:
Originally Posted by Dustball View Post
For the time being, the pump is being run manually bypassing the float. The pump runs fine without tripping the GFI. The pump is plugged in until it's all the way to the point where there is no more water then it's unplugged. Accessing the pump and float will have to wait until the ground firms up.
Dustball, this new information is vastly different from what you previously posted. See your above posts. Why are things now different?
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Old 04-02-2008, 05:29 PM   #15
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Quote:
Originally Posted by elkangorito View Post
There is no GFCI in his original problem. Really? Check the above bolded parts.



Dustball, this new information is vastly different from what you previously posted. See your above posts. Why are things now different?
In my original post, I said that plugging in either the float or the pump invidually would not trip the GFI but having both plugged in would trip it. Right now the float is out of the system- only the pump is plugged in.

Quote:
The pump has a piggyback style plug, one for the float and one for the motor I'm assuming. I can plug in one or the other without tripping the GFI but as soon as I plug in both together, the GFI trips.
The original setup was that the pump and float were plugged into the 12-2 UF cable sticking out of the ground terminated with a female cord end (unsealed). The circuit was on a dedicated 20 amp breaker, no GFI protection at all. Right now the pump is plugged into an above ground extension cord that runs to a GFI receptacle in the garage, different breaker than the original pump breaker.

The underground UF cable will be replaced shortly with cable in a conduit and a proper GFI setup when conditions allow.

I'm leaning towards a defective float switch right now.

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