Well repairs,,, OUCH!!

[MossRoad]

Came home on Monday night to find I had no water pressure from my well. Did the basic troubleshooting and isolated to either a worn pump (26 years old at best guess, replaced by previous owner) or a hole in the drop pipe.

Eight phone calls later and I finally find a well company that can get to it. Long story short, 400' of 1.25" pipe (replaced severely rusted galvanized with new SCH120 PVC), new wire (original was direct burial cable with no ground), replaced pump (increased pump to 5HP), new control box (due to upsized pump), new 86 gallon tank (replaced old air over water tank with a diaphragm tank)

$6700 bucks, OUCH!!

The good news, it should last me into retirement.

What was the reasoning for going from 1.5hp to 5hp? Seems excessive.

 

[Alan L.]

I feel your pain. I paid $5600 just last year and that was just a new pump and motor - no new pipe or cable.

 

[dave1949]

These prices seem high. Might be due to the well drilling rush going on now.

 

[DarkBlack]

I highly doubt they installed a "real" 5hp motor at the bottom of a 400' deep well.

 

[gsganzer]

I highly doubt they installed a "real" 5hp motor at the bottom of a 400' deep well.

I checked the motor nameplate and it said 5hp. I'm kicking myself for not looking at the numbers on the pump.

 

[gsganzer]

What was the reasoning for going from 1.5hp to 5hp? Seems excessive.

The reasoning was so the motor would last longer due to running at a fraction of it's service factor. Going from a 1.5hp to a 2.0hp or even a 3.0hp would have been sufficient, going to a 5hp was complete overkill and now creates a whole new set of problems.

 

[Deere Dude]

I sincerely doubt any well company will come out and change anything considering that is what they advised. Why would they; because some guys on a tractor forum thought they should?

 

[Professor Marvel]

Let see if I got this right:

• Well did not run out before latest problems.
• Well is 400+ feet deep.
• New tank is 86 gallons.
• Pump is 7 GPM

Key questions to answer:

1. What is the diameter of the well bore? 6 inches?
2. What is the static water level in the well?
3. What is he recovery rate of the well?

My well has this information on a plate attached to the well casing.

If the well bore is 6 inches in diameter, and there is 100 feet of water in the well above the pump, then there is over 140 gallons of water in well.... 50 feet of water would be 70ish gallons.

So if the pump runs 5 minutes it would only have pumped 35 gallons of water. Either the time to pump is incorrect, the GPM of the pump is higher than expected, or there is not much water in that well. 35 gallons seems like a low number if the well was working before.

Static water level vs the level of the pump along with bore size will tell you how much water is stored in the well.

7 GPM would work as long as the there was 100ish gallons of water in the well available to the pump. Since pump starts are supposed to age the pump, seems like a small GPM pump that ran longer but started less would be better.

Seems like finding how much water is available in the well bore is the key question to answer at this point.

Later,
Dan

I think Dan makes a very good point that does not appear to have been addressed.
What is the static level of the water and what is the depth of the well. Where is the pump installed in relationship between the water level and the bottom of the well? AND where was the old pump installed when it was not a problem? I think Dan said each foot of water filled pipe equals 1.4 gallons of water so how much of your total reserve in the well pipe is being used?

 

[MossRoad]

The reasoning was so the motor would last longer due to running at a fraction of it's service factor. Going from a 1.5hp to a 2.0hp or even a 3.0hp would have been sufficient, going to a 5hp was complete overkill and now creates a whole new set of problems.

Yeah. Doesn't make sense. Look at it this way.

- You still would have had to put out for new pump because the old one was dead.
- You still would have had to put out for new pipe because the old one was rotten.
- You still would have had to put out for new wiring because the old wire was not up to snuff.
- You still should have replaced the air tank with bladder tank.

So those are givens. You'd be out those things anyway.

Had he replaced it with same or near same size motor, you wouldn't need new breaker in panel, so the cost of the larger motor and the cost of the new breaker/control panel are added expenses.

As for it draining your well so fast.... would it have made a difference? Does the 5hp motor turn any faster than the 1.5hp motor? Nope. What makes the difference would seem to be the GPM capacity of the pump, not the power of the motor. Seems like either the pump is a much larger capacity than the old one or the old one was not pumping at its rated capacity.

As others have mentioned, what is the total depth of your well VS the water level in the well, and where is the pump hanging in that water column? The installer should have checked all that before just replacing the motor/pump.

 

[gsganzer]

Hello Moss, you're on the right track. I don't have any issues with most of the expense, it's just the size of the pump and motor that are causing an issue. The comments below might better explain what the real issue is.

Yeah. Doesn't make sense. Look at it this way.

- You still would have had to put out for new pump because the old one was dead.
- You still would have had to put out for new pipe because the old one was rotten.
- You still would have had to put out for new wiring because the old wire was not up to snuff
- You still should have replaced the air tank with bladder tank.

So those are givens. You'd be out those things anyway.I agree and I have no issue with any of those.

Had he replaced it with same or near same size motor, you wouldn't need new breaker in panel, so the cost of the larger motor and the cost of the new breaker/control panel are added expenses. The cost for the new control box is insignificant to the whole price, so I didn't have an issue with getting a new control box anyway

As for it draining your well so fast.... would it have made a difference? Does the 5hp motor turn any faster than the 1.5hp motor? Nope. What makes the difference would seem to be the GPM capacity of the pump, not the power of the motor. Seems like either the pump is a much larger capacity than the old one or the old one was not pumping at its rated capacity. Based on my research, I don't think the pump is the same capacity as the original. When I look up Gould pumps, the 5hp submersibles start at 10GPM, not 7GPM (Unless this is a special order pump), so it's possible I now have a pump that's approx. 50% greater capacity. In addition, the motor is grossly oversized for the depth and pressure. The problem with the oversized motor is that I can't install a "dry pump protection device", because it doesn't have a big enough delta in the current between normal operation and a dry pump condition. Normal amperage with a fully recovered well is only 10.9 amps, during a dry pump condition, the amperage only drops to 9.5amps. All of the dry pump devices I've found look for a 25% drop in current before tripping the pump.

As others have mentioned, what is the total depth of your well VS the water level in the well, and where is the pump hanging in that water column? The installer should have checked all that before just replacing the motor/pump.Well is 425' deep, pump sits at 400', static water level is 370' so pump only has 30' of water above it. I understand it's a low capacity well. The problem is I believe I have a pump that is oversized if it is a 10gpm as I suspect. The bigger problem is that because the motor is so grossly oversized, it prevents me from adding a pump protection device.

 

[DarkBlack]

Your well setup falls in the middle of a Goulds 1hp pump as far as selecting head vs gpm.
Goulds 5hp motor alone is 70 lbs.
Putting on a "real" 5hp motor is just plain bad. Now you have a huge starting torque on a 1-1/2 hp pump mass. This means your torque tube is going to shift every time that huge motor starts, as it doesn't have an accompanying mass of pump bolted on, to resist rotation. Did they put on multiple torque tubes at least? If not, you'll be replacing broken wires or a split pipe after a couple years. Besides the extra $1k for the motor you had to change to oversized copper cables to prevent a voltage drop. Those aren't cheap. And lastly, If you're like me and want your mid sized portable generator to run your pump, forget it with your pump motor.
I see only drawbacks to a grossly oversized motor.

 

[SPIKER]

I would think the easiest solution now would be to use a VFD and drive the pump as a lower speed than across the line starting being done now.

Running slower will reduce flow rate of the system letting the well fill at a rate where it (PUMP) does not suck air.

Starting slower also will keep the piping from snapping off under the increased weight/torq load the big new pump makes. System should be set up so that the pump (VFD) turns on and runs slowly for small amount of time and can even run at full speed if needed but slow down as similar rate to keep from over torquing as it slows.

Mark

 

[4570Man]

I think a VFD has to have a 3 phase motor to work, but I am not sure about that.

 

[Professor Marvel]

VFDs are available for single phase motors now. In fact I have read here about VFD controlled well pumps. They apparently remove the pressure tank altogether.

 

[TheGoose]

I'm a lic water well pump installer here in tx. All pumps over 1.5 hp come separate from the motor. I can't really comment on matching a 5 hp motor to a 1.5 pump. You can always oversize the motor to any pump end. We don't have to set our pumps that deep here on the coast either.

 

[TheGoose]

Looking at the pump curve it looks like you're only pumping 6-9 gpm when you run out of water.

 

[westcliffe01]

I don't get the point of oversizing the motor. Surely the wear limit is the pumps ability to maintain flow against the substantial head + accumulator pressure ? A larger displacement pump with a bigger motor is just going to have a faster pump down rate. It could be that the OP's issue is that the water level in the aquifer has fallen and the pump will fail rapidly once it starts sucking air. Potentially just a matter of days to a few weeks before it is toast. In such a situation, installing a bigger pump and motor is exactly the wrong medicine.

When the well was originally drilled, the driller is supposed to determine the well flow rate and then size the pump/motor accordingly. It just sounds like the driller does not have the interest of the OP at heart in the choice of actions taken with this job. Or is simply not the brightest crayon in the box and does not take a methodical approach to problem solving.

 

[CurlyDave]

I would think the easiest solution now would be to use a VFD and drive the pump as a lower speed than across the line starting being done now.

Running slower will reduce flow rate of the system letting the well fill at a rate where it (PUMP) does not suck air.

Starting slower also will keep the piping from snapping off under the increased weight/torq load the big new pump makes. System should be set up so that the pump (VFD) turns on and runs slowly for small amount of time and can even run at full speed if needed but slow down as similar rate to keep from over torquing as it slows.

Mark

This is the most elegant (and least added expense) way to resolve the problem I have seen.

The guy who sold you the oversized motor is not your friend. I think it would be difficult to get him to admit he was trying to sell you the wrong equipment, but that is exactly what he did.

A cistern and a very low flow pump is really the way to go here. Then a second pump to pressurize the house.

You may not think you need a cistern, but the very low flow rate of this well is going to cause problems if you ever have a need for more water for a short time. What happens when you have house guests and 4 (or more) people want a shower in the morning instead of just 2? You really don't want to burn out your almost-new pump and motor when someone comes to visit.

 

[Larry Jones]

I suspect that that pump-motor combination is what the driller had available and wanted to get rid of it. I think a quick and cheap solution would be to add a gate valve in the line before it got to the tank and pressure switch. Then adjust the flow so it is a little less than the well recovery. Also, for home use I think the tank is way over sized, especially for a low flow well. Use a smaller tank so it will fill and shut off the pump so it won't be making long runs with the gate valve.

 

[DarkBlack]

VFDs are available for single phase motors now. In fact I have read here about VFD controlled well pumps. They apparently remove the pressure tank altogether.

I don't think so.
Show me a VFD designed to run an off the shelf 5HP single phase deep well pump. It makes no sense to me.
They do make drives for low starting torque small single phase motors, and they make 3 phase drives that can be powered by single phase.
If you want a variable speed 5hp well pump, you install a 3 phase motor. This is a high starting torque application.
Again, show a link to this. I say if you run an off the shelf single phase deep well pump at less than rated speed, you'll have a dead motor soon.
If it's new tech it must be really new. I'm gussing you're confusing a 3 phase vfd/motor combo powered by single phase.