Control Box Replacement Questions

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Valveman

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I am only figuring a 4% voltage drop with that wire. Voltage drop up to 5% is actually a good thing as it causes a reduced voltage soft start for the pump motor. I would not change the wire. If that pump that "died" about 6 months ago had been in the well for a long time, I wouldn't make any changes. If that pump had not been in the well very long, you need to figure out the cause of failure so we can help keep it from happening again.
 

Reach4

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Attached is a zip file with a spreadsheet (pump_wires.xls) in Word 95 format, so that will be understood by whatever spreadsheet program you use.

Line 5 is your system, as I understood it.

I would not pull the pump for this, due to the factors mentioned. If you decided that later you wanted to go to a 3 HP 7 gpm pump, you can see what would be needed.
 

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Juniper Jane

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Thank you everyone! This is all most valuable information.

Won't do anything until we know for sure why the first pump died!
 

Reach4

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Note that measuring low ohms can be hard. But the the resistance on the main winding black to yellow (YL to BK) will be about 4 ohms lower than for red to yellow (RD to YL). RD to BK would be highest of all. (table 13)

Each measurement from up top will include the wire resistances, but those should be pretty much equal.

I don't know if the wires would need to be disconnected from the box to take the measurements, but power must be off. I suspect not, but if you don't get the expected results, then isolate the wires and try again.

I am not saying that the windings are miswired. It is not probable. But that current reading seemed odd, and checking seems easy enough.
 

Valveman

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Yes remove the wires from the box to check ohms. An easy rule of thumb is that using RX1 scale on a single phase motor, the two lowest readings will add up to the highest reading. So checking between R & Y, Y & B, R & B would read something like a 3, 5, and 8, or 1, 3, and 4. But that is not going to show you anything about voltage loss or how long the pump will last.
 

Reach4

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But that is not going to show you anything about voltage loss or how long the pump will last.
What would happen if somebody were to interchange the red and black wires when wiring the pump? Pump runs backwards, if at all? So I think that could not be it.

Is there a mis-wiring where the pump runs the right way, but not well? I am thinking of
box YL to pump BK
box RD to pump YL
box BK to pump RD

I know it sounds a bit outlandish.
 
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Juniper Jane

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Hello Again!

I have an electrical engineer looking at the wire set up to confirm Yay or Nay.

When connecting the Franklin Pumptec Plus to the Grundfos Standard Control Box what size wire should be used?

Right now it is #14 and it is 18" long does this work?


Thanks in advance!!
 

Reach4

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Right now it is #14 and it is 18" long does this work?
From the point of view, of working, 18 inches of #14 is insignificant resistance. So if the question is really why it is working, it is because the wire is so short. It is not like a road where the smallest road size sets the capacity. Instead it is the sum of the resistances that matters mostly. Not totally.

However the electrical codes put a minimum wire size according to breaker size. I think for a 25 or 30 amp breaker, you would need #10 to meet that requirement. Your #14 should be increased. You can buy wire by the foot, so that is not going to be a lot of money.
 

Juniper Jane

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So here is what the electrical engineers have come up with: I hope you like to read!!! Any thoughts would be appreciated .... PLEASE NOTE that these calculations are based on the Standard 2HP Grundfos Control box not the 5HP temporary box that was put on by the driller to "remedy" the problem.

A. Existing Project Data:
1. House Service is 100A-120/240V-1PH-3W
2. There is a subpanel, located near well pump controllers, which is supplied by a 50A-
120/240V-1PH-3W feeder, derived from house service. The feeder specification is 160
linear feet of 3#2 stranded aluminum – 2”C.
3. The subpanel supplies the Grundfo’s well pump / Pumptec protective device (13.2FLA-
240V-1PH load) – Feeder spec is 5 linear feet of 3#6 THHN (CU) – 1”C. The Pumptec
protective device supplies the well pump via the Grundfo’s control box (Contactor Load –
5 Watts).
4. The Grundfo’s pumptec protective device supplies the Grundfo’s well pump, via control
box. The pump is rated at 2HP (13.2FLA)-240V-1PH. Feeder spec consists of:
 400 Linear Feet of 3#8 THW Submersible pump cable, plus
 220 Linear Feet of 3#10 THW Submersible pump cable.

B. Voltage Drop Calculations:
The voltage drop calculation is broken into (4) individual calculations and runs, which sum
together to conclude total voltage drop, as follows:

VD1 – From House Service to Subpanel (2”C-3#2 Aluminum – 160 Feet)
VD1 = 2 x L x R x I / 1000
= 2 x 160’ x 0.32 x 13.22A / 1000 = 1.4V

VD2 – From Subpanel to Well Pump Pumptec Protective Device (1”C-3#6 Copper – 5 Feet)
VD2 = 2 x L x R x I / 1000
= 2 x 5’ x 0.49 x 13.2A / 1000 = 0.06V

VD3 – From Grundfo’s Control Box to Well Pump Branch Circuit
Splice Point (3#8 CU THW submersible pump cable – 400 Feet)
VD3 = 2 x L x R x I / 1000
= 2 x 400’ x 0.78 x 13.2 / 1000 = 8.2V

VD4 – From Well Pump Branch Circuit Splice Point to Well Pump (3#10 THW
submersible pump cable – 220 Feet)
VD4 = 2 x L x R x I / 1000
= 2 x 220’ x 1.2 x 13.2A / 1000 = 7.0V

Total Voltage Drop:
VD1 + VD2 + VD3 + VD4 = 16.8V

Percent Voltage Drop Lost = 16.8V / 240V = 7.0%

C. Recommendations:
The California Energy Commission (CEC), as part of their Title-24 code, mandates a
maximum voltage drop of 5% to farthest outlet of power, and 5% maximum voltage drop is
also recommended by the National Electrical Code (NEC) in order to provide reasonable
efficiency of operation.

If feeder (VD4) was changed out to #8 conductors, the voltage drop on this run would be
reduced to 4.5V for an overall voltage drop of 14.3V or 6.0% total – Still exceeding Title-24
code and NEC recommendations.

If feeder (VD3) was changed out to #6 conductors, the voltage drop on this run would be
reduced to 5.1V for an overall voltage drop of 13.7V or 5.7% total – Still exceeding Title-24
code and NEC recommendations.

Recommendation: Upgrade the branch circuit conductors (VD3 and VD4) to 3#6AWG
THW CU submersible pump cable. The new VD3+4 calculation is as follows:

VD3+4 = 2 x L x R x I / 1000

= 2 x 620’ x 0.49 x 13.2 / 1000 = 8.0V

Total Voltage Drop:
VD1 + VD2 + VD3+4 = 9.5V

Percentage Voltage Drop Lost =
9.5V / 240V. = 4.0%
 

Valveman

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Wow! Good job figuring the voltage loss for each individual branch. But I went back and read this thread and I still don't know what you are trying to fix? Did the first pump only last 6 months? Or are you just worried about the 5HP control box on a 2HP motor?

Those motors will work with plus or minus 10% of rated voltage. I think they will be fine from like 220V to 260V. Having a 16 volt loss doesn't seem that bad to me. It also depends on the incoming voltage. If it is coming in at 240V or more, losing 16 volts shouldn't be a problem. But if the incoming voltage is low, you can't afford much loss.

Also as the voltage gets lower the amperage will increase. If the voltage gets too low the overload in the motor will trip. If it not doing that I don't think you have a problem.
 

Juniper Jane

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Wow! Good job figuring the voltage loss for each individual branch. But I went back and read this thread and I still don't know what you are trying to fix? Did the first pump only last 6 months? Or are you just worried about the 5HP control box on a 2HP motor?

Those motors will work with plus or minus 10% of rated voltage. I think they will be fine from like 220V to 260V. Having a 16 volt loss doesn't seem that bad to me. It also depends on the incoming voltage. If it is coming in at 240V or more, losing 16 volts shouldn't be a problem. But if the incoming voltage is low, you can't afford much loss.

Also as the voltage gets lower the amperage will increase. If the voltage gets too low the overload in the motor will trip. If it not doing that I don't think you have a problem.

The well was installed brand new in March 2016.
The original Grundfos Pump died in July 2017.

The issue began with a continuously decreasing flow of water from the time it was installed until the pump finally died. There is 80 feet of water above the pump. When the new pump was installed in July 2017 they did not replace the original control box (2HP).

In October of 2017 (3 mos after new pump went in) the Pumptec began throwing the solid orange light every 5 to however many minutes. The well drillers said it was from high winds in our area. We began monitoring with a log how many times this happened until it wouldn't stay on at all. They came out in February (last month) and installed the 5HP control box to solve the problem. So far it stays running BUT the water yield has gone from 4.5 gpm to about 2.2 gpm since February (last month). It still has 80 feet of water above the pump that stays continuous according to the draw down gauge they installed.

SO, if the first pump went out in 18 months, and the new pump is already having yield issues (even with the 5HP box) my idea is that he may have wired my well to take a 1.5 HP pump. He did mention that size in the beginning of the project but we decided on a 2HP pump. When he installed the wire he told me he was putting in larger than necessary wire so I could upsize my pump in the future if I wanted to.

Before I meet with him regarding the oversized Control Box as a remedy - I decided to investigate per recommendations on this thread as to why the original pump died so soon. The engineering report is all I have to present him when we meet to discuss why the yield is lessening AGAIN. I am no expert but from research I have done I noted that all experts recommend a 3% line loss and a maximum 5% line loss.

My thinking is that if the experts want 3% and NEC wants 5% MAX then the calculations from the engineer showing a 4% drop from house to Motor should be optimal?

I hope all this makes sense - my brain HURTS!!! I just wanna bake cookies! LOL

Thanks for your reply, your information is invaluable!

PS: I looked in the Grundfos Manual for the wiring specs and according to Grundfos the maximum footage for #8 wire is 620 feet. So the #10 he spliced in there weirded me out. The chart shows #6 wire could go all the way to max depth of 970' which seems to be in agreement with the engineering guy.

Jane
 
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Reach4

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Your EE calculations look good.

My thinking is that if the experts want 3% and NEC wants 5% MAX then the calculations from the engineer showing a 4% drop from house to Motor should be optimal?
Nominal power from the utility is usually 240. Nominal voltage for the pump is 23o. That would seem to give you an extra 4% to work with.
 

Valveman

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I just think your pump/motor damage is more likely from a lack of flow than from low voltage. In 5" casing you need to be pumping 7 GPM to keep the motor cool. If you have a 4" flow inducer sleeve (shroud) on the pump it will stay cool down to 1.2 GPM. Even in 4" casing the motor could be getting hot while you are pumping out the 80' of water above the pump. Water doesn't start coming from below and keep the motor cool until you have pulled the 80' of water off the top. I would think a flow inducer sleeve is more important than anything with those well specifications.

Like I said, if the voltage is low the amperage will be high and the overload will trip, not the under-load.
 

Juniper Jane

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I just think your pump/motor damage is more likely from a lack of flow than from low voltage. In 5" casing you need to be pumping 7 GPM to keep the motor cool. If you have a 4" flow inducer sleeve (shroud) on the pump it will stay cool down to 1.2 GPM. Even in 4" casing the motor could be getting hot while you are pumping out the 80' of water above the pump. Water doesn't start coming from below and keep the motor cool until you have pulled the 80' of water off the top. I would think a flow inducer sleeve is more important than anything with those well specifications.

Like I said, if the voltage is low the amperage will be high and the overload will trip, not the under-load.

It was definitely the solid yellow/orange light that says under-load not the flashing light for overload.

I found in the Grundfos Manual where it states: a flow inducer or flow sleeve must be used if the water enters the well above the motor or if there is insufficient water flow past the motor. I am beginning to think I may have both of these conditions and I know I do not have one of these inducers on the motor!

So if I have a 5 GPM pump how can it pump at the required 7 GPM?? I have no idea how much water is flowing past the motor. I found a table on the internet but it only deals with empty pipes and feet per second. I hope the pump wasn't sized wrong too :(

I looked on my well completion report and it states estimated yield is 10 GPM (states that may not be representative of a wells long term yield) but there is no drawdown information at all - both areas test length and total drawdown are blank.

My 5" casing is slotted and I have a feeling most of the slotting is above the pump. The bottom of the 5" casing was left open (he said so it could be drilled deeper later or something like that) but who knows if it is still open?

The pump was raised to 605' when it was replaced because it wouldn't go back in all the way. None of the original 620' of wiring was removed - it was looped and taped to the drop pipe.

Also, I have tried several times to communicate with Grundfos but they are impossible to get help from. I have emailed and called. On the other hand, Franklin seems to be super customer service oriented and did answer an email I sent them. If I have to pay for a new system I will highly consider using Franklin products.

I would like the meeting with the driller to go as smooth as possible and not be offensive to him in any manner. Thank you for your help I am truly learning a TON and I know being somewhat educated will help me have a much more logical discussion with him.

Jane
 

Valveman

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With a 4" flow inducer that motor will stay cool down to 1.2 GPM. Without a flow inducer you are not getting enough flow past the motor to keep it cool. That would be very easy to tell by looking at the old failed pump, as the thrust bearing will be down. Also any extra wire should be taped in LONG loops down the well. If rolled into a small roll it can act like a transformer and actually change the voltage to the motor. See the pic of how to install a 4" flow sleeve. Oh and Franklin has better customer service because their pumps are not as good as Grundfos.
shroud 3 pics.jpg
 

Juniper Jane

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OH my! Thank you for the extra step of posting the pics with your reply!

My well driller said Grundfos was the best and I really don't doubt that but with a second failing pump I began to wonder. I am sure it's the water flow like you say. Once we get to meet with the driller we can figure all this out.

If he won't work with us, at least I will know enough to correct the problems. I still have water even with the issues so that's the good news!

He is a very reputable driller and I want to give him a chance to get this right after two years, but I am torn between giving him another try or changing to a different company.

My gut says stay with the original guy -any thoughts?
 

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ONE YEAR LATER - WELL UPDATE.

It's official. The pump finally died like we all knew it would. So for a double check here is what we have: The replacement pump will be set somewhere around 605 to 615 feet. Static water is at 87 feet. Casing is 5" steel.

Been trying to use the Grundfos pump curve charts to figure out the correct pump size. I give up. I would to like to achieve 5 gpm (well will produce more but we only need 5 gpm).

The pump is a Grundfos 5S20-39 (4")
The Motor is an MS4000 - (I am wondering if it is to small??)
What HP would you recommend to keep it in the correct pump curve?

Any suggestions on pumps and/or motors would be greatly appreciated! :) :) :)

NOTE: This time we are getting a down hole videolog before the new pump goes back in. Open for all suggestions here, too.

Thank you!!!
 

Reach4

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It's official. The pump finally died like we all knew it would. So for a double check here is what we have: The replacement pump will be set somewhere around 605 to 615 feet. Static water is at 87 feet. Casing is 5" steel.

Been trying to use the Grundfos pump curve charts to figure out the correct pump size. I give up. I would to like to achieve 5 gpm (well will produce more but we only need 5 gpm).

The pump is a Grundfos 5S20-39 (4")
The Motor is an MS4000 - (I am wondering if it is to small??)
What HP would you recommend to keep it in the correct pump curve?
I would choose the
5S15-31 with a 7 or 8 gpm dole valve, or a 7S20-32 with a 10 gpm Dole valve.
img_5.png
 
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