2 vs 3 wire well pump

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illrohan

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After closing on our first home I noticed my press tank needed to be replaced. While doing so I installed a new press switch and a CSV as well for good measure. After opening up the pump controller I did some head scratching. I found that the wiring for thE original 3 wire pump had been reconfigured to that of a two wire pump, eliminating the need for a controller. I'm wondering why then would you want a three wire pump that requires an additional piece of equipment (pump controller) when a two wire pump does the same job without the added cost of a controller?
 

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Boycedrilling

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The most failure prone components for a pump are in the control box on a 3-wire pump. The are inside the motor on a 2-wire pump. If and when they fail, do you want to have to pull the pump or just replace the components in the control box on the wall?

2-wire vs. 3-wire pumps is a regional thing. Some areas of the country that's about all you see. Other areas, like where I live, about the only place you can hardly buy a 2-wire pump is in a big box DIY store. The pump wholesalers don't even stock them here. They couldn't give them away even if they were free. Other areas of the country, professional installers use them all the time. It's almost like Coke vs. Pepsi. I'll drink water before I'll drink a Coke.
 

Craigpump

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A lot of pump guys use 3 wire pumps on new installs, some guys use 2 wire pumps, it's mainly a matter of preference. If your home is older, there may not be a 4 th wire required for the ground so the installer used a 2 wire pump and then dedicated one of the original 3 wires as the ground.
 

Valveman

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It is all about the starts. The third wire of a three wire motor is basically only in the circuit for a split second until the pump starts. Then even a three wire motor is running on two wires, just like a two wire motor. Third wire is the capacitor start from the control box. So it has more starting torque when there is sand or debris in the water, and it will tolerate rapid cycling more than a two wire motor. Two wire motors normally either use a Biac switch or a split phase capacitor for starting. With that CSV1A you shouldn't have to worry about motor starts either way.

Really nice install BTW.
 

illrohan

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It is all about the starts. The third wire of a three wire motor is basically only in the circuit for a split second until the pump starts. Then even a three wire motor is running on two wires, just like a two wire motor. Third wire is the capacitor start from the control box. So it has more starting torque when there is sand or debris in the water, and it will tolerate rapid cycling more than a two wire motor. Two wire motors normally either use a Biac switch or a split phase capacitor for starting. With that CSV1A you shouldn't have to worry about motor starts either way.

Really nice install BTW.
oh man, thanks for that. i appreciate it. I'm BRAND new to well water systems so there's a level of uncertainty in my work that I'm not used to. When this pump goes I will def opt for a three wire. Seems like a no brainer. I would obviously want to avoid pulling a pump 320' if possible.
 

illrohan

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The most failure prone components for a pump are in the control box on a 3-wire pump. The are inside the motor on a 2-wire pump. If and when they fail, do you want to have to pull the pump or just replace the components in the control box on the wall?

2-wire vs. 3-wire pumps is a regional thing. Some areas of the country that's about all you see. Other areas, like where I live, about the only place you can hardly buy a 2-wire pump is in a big box DIY store. The pump wholesalers don't even stock them here. They couldn't give them away even if they were free. Other areas of the country, professional installers use them all the time. It's almost like Coke vs. Pepsi. I'll drink water before I'll drink a Coke.
w5l(
Makes me wonder why they would have replaced the old burnt out 3-wire motor with a 2-wire motor. I personally would have chosen to add a fourth ground wire at that time if that were their concern.
 

Reach4

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Pumps with bigger motors tend to be 3 wire. I suspect 2-wire is more common with 1/2 HP, and maybe 3/4 HP. The capacitor in a normal 3-wire control box has a limited lifetime (non-polarized electrolytic, which is two electrolytics in series in one package), and I suspect that few people routinely replace them.

I don't know if higher starting torque is always good. The 2 wire Franklin motors make this claim:
Bound Pump (Sandlocked)
When the motor is not free to turn, as with a sandlocked pump, the BIAC switch creates
a “reverse impact torque” in the motor in either direction. When the sand is dislodged,
the motor will start and operate in the correct direction.​
 

Craigpump

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w5l(
Makes me wonder why they would have replaced the old burnt out 3-wire motor with a 2-wire motor. I personally would have chosen to add a fourth ground wire at that time if that were their concern.

Depends, if the wires is in a conduit from the well to the house a new string of wire could be pulled through. If the wire was direct buried it would be more difficult & expensive.

We stock complete two wire pumps on the truck along with 3 wire motors to match the application.
 

illrohan

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Something unknown is going on. It seems as though no water is filling into my press tank. I even reconfigured the piping to see what would happen but press is dropping slowly from 50 psi to about 25 then drops abruptly to 0. the pump doesn't seem to be able to keep up with a simple lav cold water faucet.
20170312_144907.jpg
 
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Reach4

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You have a ball valve on the left. I would see if I could adapt a 200 PSI pressure gauge to fit there.

I don't see a valve on the output pipe on the right. Maybe it is out of the picture. Are you saying that the pressure drops even when you are not using water? If you have a valve for the water to the house try closing that and see if the pressure holds.
 
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JRC3

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Sounds like you might have 2 problems...

Is that switch a pump saver? When the pressure hits 25# does it throw the contacts open as soon as it cuts on? Is the precharge set too high on the PT? When I first installed mine (preset to 38) the (30/50) switch hit 30 and go to cut on and then turn immediate off and the pressure would dump to zero. Get a good tire gauge. Most of the cheap ones are off by a few pounds.

Valveman would know best but have you tried turning the csv adjusting bolt all the way out to see if it keeps up better than it's not doing with the lav faucet? Or should it be adjusted tighter? That would just bring up the pressure, right? I think it needs adjusted all the way out.
 

illrohan

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You have a ball valve on the left. I would see if I could adapt a 200 PSI pressure gauge to fit there.

I don't see a valve on the output pipe on the right. Maybe it is out of the picture. Are you saying that the pressure drops even when you are not using water? If you have a valve for the water to the house try closing that and see if the pressure holds.
There is a shut off for the house just out of frame above the red coup.
The pump can't even make 50 psi sometime's, other times barely.
100psi gauge is on the csv with the switch
 
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illrohan

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Sounds like you might have 2 problems...

Is that switch a pump saver? When the pressure hits 25# does it throw the contacts open as soon as it cuts on? Is the precharge set too high on the PT? When I first installed mine (preset to 38) the (30/50) switch hit 30 and go to cut on and then turn immediate off and the pressure would dump to zero. Get a good tire gauge. Most of the cheap ones are off by a few pounds.

Valveman would know best but have you tried turning the csv adjusting bolt all the way out to see if it keeps up better than it's not doing with the lav faucet? Or should it be adjusted tighter? That would just bring up the pressure, right? I think it needs adjusted all the way out.

I used a "pump saver" type preset at 40/60 first, then the same issue with the cheaper 30/50 non ps type.
The press drop I'm referring to is when one cold water lav faucet is left open. CSV is suppose to be press set with 2-3 gpm in use.

I did check my PT preset. I have a good gauge. Its set at 2 psi lower than the cut in (30psi) of my switch. Respectively, I had it set at 38 when I had the 40/60 switch installed
 

illrohan

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You guys don't think I just have a crap pump? It's a two wire pump so maybe it's "built-in" cap went bad?
 

illrohan

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Pumps with bigger motors tend to be 3 wire. I suspect 2-wire is more common with 1/2 HP, and maybe 3/4 HP. The capacitor in a normal 3-wire control box has a limited lifetime (non-polarized electrolytic, which is two electrolytics in series in one package), and I suspect that few people routinely replace them.

I don't know if higher starting torque is always good. The 2 wire Franklin motors make this claim:
Bound Pump (Sandlocked)
When the motor is not free to turn, as with a sandlocked pump, the BIAC switch creates
a “reverse impact torque” in the motor in either direction. When the sand is dislodged,
the motor will start and operate in the correct direction.​

I'm not even sure what pump is down there, other than being of a two wire variety. My motor is struggling to make press. Even as low as 40 psi.
 

Reach4

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You guys don't think I just have a crap pump? It's a two wire pump so maybe it's "built-in" cap went bad?
You may have a defective pump. There could be a blockage or a hole somewhere.

press is dropping slowly from 50 psi to about 25 then drops abruptly to 0.
That would normally go along with the precharge at 25. But not if the pump was delivering water. Are you sure the pressure switch is delivering power to the output wires while that pressure fall was happening? How much water was being used during that time the pressure is falling?

Are you sure you turned the adjustment in enough? http://www.cyclestopvalves.com/pdf/install_csv1a.pdf
 

Valveman

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Yeah tighten the adjustment bolt on the CSV a few rounds to the right. That will bypass the CSV and make it work like a piece of pipe. Then if it doesn't build to 60 you have a pump problem.
 

Craigpump

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You guys don't think I just have a crap pump? It's a two wire pump so maybe it's "built-in" cap went bad?

Is your power bill high?

Could be any of the following,
Rotted brass adapter
Split coupling in drop pipe
Worn out pump
Leak between well & house
Hole is discharge head of pump
 
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