submersible pump cycling on (2 sec.) and off (20 sec.)


  #1  
Old 09-17-05, 06:07 PM
makinen
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Exclamation submersible pump cycling on (2 sec.) and off (20 sec.)

My father-in-law's submersible well pump recently started cycling on and off. He has a 120 volt 4" Nautilus pump suspended at 60' in a 105' deep 6" dia. well, pressure tank with bladder, Square D pressure switch and dial pressure gauge. I checked the gauge and it was at about 15 psi. I took the cover off the pressure switch and the contacts were closed. With the faucets turned off the pump would run for 2 sec. and then shut off for about 20 sec. and the pressure would go up about 3 psi. This cycle continued until the gauge read 50 psi and then the contacts opened and the pump shut off. We opened a faucet to draw down the tank. The contacts closed again at about 25 psi and the pump started up and returned to its cycling ( 2 sec. on and 20 sec. off). Is there some thermal protection in the pump that is causing this on-off cycling? Thanks for the help.
 
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Old 09-18-05, 08:31 AM
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It seems like I replied to this thread before.

I don't think a thermal overload would come back on that quick, especially after several trips. The motor will be quite hot after several trips and will take some cooling down to reset the overload.

It sounds like your pump is setting almost out of the water. Lowering it might cure the problem.

You might want to check the tank too.

bob...
 
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Old 09-18-05, 11:02 AM
makinen
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Bob

Thanks for the reply. The water in the well comes within 2' of the surface so there is plenty of water above the pump. Someone at church today said that it is quite common for wells in this area to sand up and need hydrofracting to open them back up. The well is 13 years old so that could have happened. He suggested that I drop a weighted line down the well to measure the distance to the bottom which would tell me if sand is filling the well. I didn't check the tank because the pressure switch contacts closed at 25 psi and opened at 50 psi as I expected they would. I am still puzzled as to why the pump only runs for 2 sec. and shuts off even though the closed pressure switch contacts are telling it to continue running. Thanks.

Doug
 
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Old 09-18-05, 11:15 AM
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The reason would be the pump not being in water. I don't know when you checked it last, but you might want to check it again.

If the well was sanding up as you said, you would have a house full of sand as well.

bob...
 
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Old 09-18-05, 02:21 PM
makinen
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Bob

I checked the water level when I first posted this thread on 9/17/05 and it was 2' below ground level. The pump definitely has 50 plus feet of water above it. Thanks for the info on the sanding condition.

Doug
 
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Old 09-18-05, 05:03 PM
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Do you know the production capability of this well in gallons per minute?

bob...
 
  #7  
Old 09-18-05, 06:23 PM
makinen
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According to my father-in-law, when the well was drilled 14 years ago, the well driller pumped water from it at 15 gals./min. for 8 continuous hours which drew the level down to 60'. When the pump(s) were turned off, the well filled back up to within 2' of the surface in about 1 min. Does that answer your question?

Doug
 
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Old 09-19-05, 06:04 AM
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That is very good, but 14 years ago. I mean now?

If this is a screened well, the screen is probably plugged and not producing water like it was when it was first drilled.

Beyond that, I can't think of anything else causing what you are describing.

bob...
 
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Old 09-19-05, 03:19 PM
makinen
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Thanks for all your help Bob. I'll let you know how things turn out.

Doug
 
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Old 09-20-05, 10:46 AM
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Ok keep us posted.

bob...
 
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Old 09-22-05, 10:39 AM
makinen
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Smile

The capacitor in the control box was blown. Don't know what caused that - it could have been a nearby lightning strike. Installed a new control box, reset the pressure tank precharge to 28 lbs. and set the cut in and cut out to 30 and 50. The pump works great now. Thanks to everyone for your help.

Doug
 
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Old 09-22-05, 11:15 AM
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I'm thinking something is still wrong. If the capacitor was blown, the motor won't start. That is the function of the start capacitor, key word being "start". If it was blown, the motor wouldn't start.

In your first post you said: "With the faucets turned off the pump would run for 2 sec. and then shut off for about 20 sec. and the pressure would go up about 3 psi. This cycle continued until the gauge read 50 psi and then the contacts opened and the pump shut off. We opened a faucet to draw down the tank. The contacts closed again at about 25 psi and the pump started up and returned to its cycling ( 2 sec. on and 20 sec. off). Is there some thermal protection in the pump that is causing this on-off cycling"

If the pump was starting and stoping like you mentioned above the cap had to be good. Now I grant you if the motor kept doing that for not too long a time, the start cap would most certainly go bad. The switch points and relay would probably go next if left in the same condition. With the start windings not far behind.

So if the cap is good, the pump motor could start. If the cap is bad, the motor can not start. I hope this makes sense.

bob...
 
  #13  
Old 09-22-05, 03:31 PM
makinen
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Bob

After installing the new control box, the pump starts at 30 psi, runs smoothly up to 50 psi and stops when the contacts open. We ran the water steadily through about 5 cycles of the pump turning on at 30 psi and off at 50 psi as I was fine tuning the pressure switch and it performed beautifully. The 2 secs. on and 25 secs. off cycle is gone and whether or not it was the capacitor, something in the new control box seems to have cured the problem. When I took the cover off the old control box, I found pieces of a black tar-like substance and traces of a clear oily liquid in the box and on the bottom of the capacitor. I used the term blown capacitor to describe this - I don't know what the correct term should be. I'm happy that it's working now and I'll post again if it fails down the line.

Doug
 

Last edited by makinen; 09-22-05 at 07:23 PM.
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Old 09-23-05, 05:43 AM
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OK Doug, I hope it don't fail again.

bob...
 
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Old 09-23-05, 06:47 AM
makinen
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Thanks Bob, me too.

Doug
 
 

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