3 Wire vs 4 Wire Submersible Pump

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Old 02-25-14, 09:05 AM
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Question 3 Wire vs 4 Wire Submersible Pump

I need to replace my 1hp submersible pump. It has a control box that is located away from where the pump is located. All of the data that I am reading says that if I have a control box, I need a 4 wire pump (3 wires plus ground). Only problem is my pump only has 3 wires. I was told by someone, that the older pumps with control boxes only had 3 wires. So, if I am replacing the current pump, with a new one that uses an external control box, do I need to string extra wire from the control box to where the pump is located??? This is all underground and the distance is about 100 feet, probably with current wire run through a plastic conduit, but not sure. What are my options?? Can I replace with a pump with internal control box and just not use the external control box?? Is this an option???
 
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Old 02-25-14, 06:16 PM
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hi jim Ė

Iím no well guy or expert to say the least, but I have submersible pump with a control box.

I think what is called a 3-wire motor for the pump actually has 4 wires: red, black, yellow, and green.

What is called a 2-wire motor for the pump actually has 3 wires: I believe they can be 2 blacks and a green, or a red, black and a green, or even a black, white, and a green.

The green in all of these cases is a ground wire.

The 3-wire is the one that uses the control box. It has a capacitors and relays and uses the red wire to start the motor, then switches to the black wire to keep the motor running. As far as I know the 2-wire does not use a control box, everything needed to start the motor and keep the motor running is with the motor itself.

So if you are using a control box as far as I know there should be 4 wires from the pump connected in the control box (i.e. the red, black, yellow, and green). However, in my control box there is no green. There are in fact 4-wires that come up from my well pump into a pit, but the installer never continued with the green (ground) wire from the pit into the control box in the basement. So I just have the red, black and yellow in my control box.

Is it possible you are only seeing 3 wires from the pump because the ground wire (green) is missing?


p.s. forgot to say that it seems there are different opinions about which is better: 2-wire or 3-wire. Here is an expert (I guess?) on the link below saying this:

The cost for a two wire pump or a three wire with/control box is usually the same . But for my money, I will stick with the two wire. It has been proven to last longer, it is easier to install and you donít have to look for a mounting spot for the control box.
But Iíve heard others say that with a control box you can do some repairs without the expense of pulling up the pump, so itís better! So who knows? LOL

Two vs. Three Wire Motors - Pumps - PumpsAdnTanks.com
 

Last edited by zoesdad; 02-25-14 at 06:46 PM.
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Old 02-25-14, 07:14 PM
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Only see 3 wires.

Have checked the wiring into the well casing and there are only 3 wires. Red, black and green. Also checked the wires coming out of the control box in the house and there are only 3, red, black and green. Have not yet pulled out the pump (100 feet down) so cannot verify where the 4th wire went. Again, I was told that the earlier versions of pumps with external control boxes had only 3 wires vs 4 nowadays. Question is where do I go from here if this is true. Can I just install a two wire (really 3) and bypass the control box in my basement??
 
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Old 02-26-14, 08:36 AM
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Where are those pros when you need them? LOL

I have heard of cases where someone replaced a 3-wire pump with a 2-wire pump and just left the control box. I thought what they meant is that the used the control box as a junction box and just connected wires together in the control box, really not using the control box at all. I guess that would mean that L1 and L2, the house voltage, would just be connected directly to the red and black from the pump in the control box, really then bypassing everything in the control box.

I never came across the idea that some older 2-wire pumps used a control box but I certainly believe what you are saying. Must really be old because all of the troubleshooting info you seem to get now never seem mentions that. For example:

http://www.ruralking.com/media/blfa_...tart_Guide.pdf

Doesnít your control box have some kind of label on it as identification? Did you check the wiring connections in the control box to see if maybe it is actually being used as a junction box only? In other words L1 and L2 are connected directly to the red and black in the control box?

If you have 3 wires running down to the pump looks like you could just replace the pump with a 2-wire pump with no control box, wiring as in the link above. L1 and L2 come from your pressure switch and those would be connected to the red and black of your new pump. Since definitely today you do not need a control box with a 2-wire pump.
 
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Old 02-26-14, 09:11 AM
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You know, that is what has me puzzled. The unit was installed in 2002, so not that old. It is a Franklin American control box. I believe the pump is an AY McDonald. Wires coming into the box from the pressure switch: black to L1, White to L2 and ground to the box's ground. Wires going to the pump: Black from the B junction, Red from the R and Green from the Y. Nothing going to the pump from the ground. I'd attach a picture, but it is too large a file to attach. I have checked all of the wiring and even checked continuity and it all checks out. So am pretty sure the pump has gone out. Just don't know where the 4th wire is. I guess the safest thing to do is pull the pump and see if it has a ground that is just not connected to anything. I have heard that happens as well. Then I can make a decision as whether to go with a 2 wire or 3 wire. Thanks for all of your advice and information.
 
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Old 02-26-14, 09:26 AM
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Can't help you on the pump but:
I'd attach a picture, but it is too large a file to attach.
Are you using the document attach feature under the Advanced Editor box? If so that is not for pictures . You need to use the Insert Image button at the top of the Advanced Editor. http://www.doityourself.com/forum/el...-pictures.html Also you can reduce file size using the free program IrfanView.
 
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Old 02-26-14, 09:50 AM
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Added URL

I tried to upload from my computer. It says the max jpeg size I can upload is 50 kb. The picture I tried to upload is 2.5 mb. So will have to either try to reduce the file size or put it somewhere where I can attach the URL. THanks for the info.

Lets see if this URL works. I put on photobucket.

jskach1's Library | Photobucket
 

Last edited by jimslax; 02-26-14 at 10:09 AM. Reason: adding URL
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Old 02-26-14, 10:02 AM
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Wonder why the green from the pump would be connected to the yellow in the control box? Could that be a clue to whatís going on there? Seems like there would be no reason to connect the ground from the pump to the yellow, why wouldnít the ground from the pump be connected to the control box ground? But I guess you always have to worry that someone wasnít too concerned about the color of the wires they were using thus confusing everyone. So I guess like you say, you wonít know until you pull the pump.

Maybe they had a coil of red,black, green wire on the truck, and use that instead of red,black, and yellow? So it is a 3-wire pump? Guess you won't know until you pull the pump as you say.

But maybe you could run those wiring connections by the guys in the electrical forum. I know it was either on this site or another site there were a couple of guys on the electrical forum that knew everything there was to know about submersible pump electrical connections. Just a thought!

Good luck however. If you get some time when you are done see if you can post back with the results. Iím sure it would be helpful to everyone.
 
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Old 02-26-14, 10:15 AM
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I did add some pictures below. If this is a pump that has 4 wires, but is only using 3, the wiring in the control box makes sense. It is using the capacitor in the control box. The pump did work for 12 years so it must be wired correctly. Just have to pull it to see what goes.
 
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Old 02-26-14, 11:39 AM
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Rotated your image for you.

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Size:  36.1 KB
 
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Old 02-26-14, 05:30 PM
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Donít want to beat this to death jim, I know you are busy so no need to answer. But this is what I am guessing the pump installer may have used because he might have had this from installing 2-wire pumps:

Submersible Water Well Pump Wire 10 2 with Ground | eBay

At your pump I bet youíll find a red, yellow, black, and green leads. He simply did not connect the green pump wire to anything because the pump will still work without a ground. He then connected pump red to cable red, pump black to cable black, and pump yellow to cable green. In other words, he just left off the ground and thus was able to use his red/black/green 2-wire pump cable for a 3-wire pump.

Maybe? LOL
 
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Old 02-26-14, 06:01 PM
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With red, black and green..... just install a standard self contained submersible pump.
You would no longer need the Franklin control box.
 
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Old 02-26-14, 06:18 PM
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You are probably correct

Zoesdad, I think that you have the right idea. But I wont know until I pull the pump. Unfortunately, I wont be able to do that until it gets a little warmer. If that is the case, then I need to make a decision as to which type of pump is the best for the money. I'll let you know what I find out and what my decision is, probably late March. Looks like I can go either way. Thanks for all the input. Good forum.
 
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Old 03-29-14, 04:47 PM
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Pump is a 3 wire (plus ground) But impeller is frozen. Pump ok.

Pulled the pump today and found that it is a 3 wire plus ground. The ground wire coming out of the pump is grouped with the rest of the wires almost all of the way up the flexible pipe coming out of the pump. About 10 feet from the end of the flexible pipe that is attached to the pitless adapter at the other end, it is just left dangling, attached to nothing. So now I know what to purchase if I need it. But now have another problem. I tested the pump out and found that the pump is ok, but the impeller portion doesn't work. It is frozen. I took it apart and found that a couple of the plastic impellers appeared to have melted together. Don't know if I can replace them or not. So if I cant replace them, then need to decide whether to replace the entire unit or just replace the impeller portion. Any Ideas or suggestions???
 
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Old 03-29-14, 05:06 PM
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I have replaced several pumps but never tried to repair one. In general, a three wire pump is used when there is possibility of sand in the water or there is a high head pressure. Either one could cause high starting loads on the motor. The three wire system uses a starting winding that is switched in on pump start-up thru a magnetic relay. A two wire pump will work just as well in clean water and/or low head head pressure. I would replace the whole thing. You don't know what caused the melted impellers.
 
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