How to Recover a Lost Submersible Well Pump

[Egon]

My well is 600ft but they hung the pump at 360. They know the water table levels in the area and the drawdown. It's much cheaper to not hang it at say 550 ft. The deeper you hang it... more pipe, more wire, bigger pump for the added head.

No added head.

 

[Chewwy]

'The deeper you hang it... more pipe, more wire, bigger pump for the added head.'

With all due respect - you may want to study pump sizing a little bit more.

Just saying.

???

 

[Chewwy]

No added head.

Only if you ignore the velocity head of the addtional pipe.

 

[etpm]

I had to chlorinate due to iron reducing bacteria which creates sulphur gas when it attacks the anode in the water heater. The freq drive turns the pump into a variable speed that allows soft starts and maintains a constant 50 pounds of pressure. This setup is like a Cadillac compared to the old jet pump!

I'm curious about how your well control works. I have several motors in my machine shop controlled by Variable Frequency Drives, AKA VFDs. Your situation must somehow sense demand which then tells the VFD to alter frequency so that the pump speed changes.
Most of the drives in my shop are controlled by the machine control but I do have a couple controlled by just me. The machine control is part of the expensive CNC control. The drives I control I understand and so control is no issue with me.
Having a well controlled by a VFD worries me because I may be locked into the device that senses demand and also locked into a particular VFD. VFDs are now so common that they have become really inexpensive. But the control interfaces vary quite a bit. If your VFD fails can you just buy another one with the same or better specs? And use it with the existing control?
The advantages of a 3 phase motor pumping the water, I think, can't be argued with from an electrical efficiency standpoint. But from a reliability standpoint I'm not so sure. Even though inverter power supplies, which is what VFDs are at heart, are very well understood, most of them are now made to satisfy a certain price and quality suffers because of this.
If the pump demand control interfaces with a generic VFD that would be great. A person could buy a generic VFD and just keep it for when the original one fails. Less that 100 bucks for a 2 HP VFD. But if the thing needed to be bought from a specific supplier then when the drive fails the cost will probably be a couple thousand.
Just my opinion of course after speaking to a couple electricians installing the new variable speed pump systems. So not a very big sample. Still, I'm curious.
Thanks,
Eric

 

[LouNY]

Most VFD's are set up for a variable input, be it voltage or current. And pressure transmitters/transducers are quite inexpensive that can provide the signal to a VFD.

 

[Egon]

Only if you ignore the velocity head of the addtional pipe.

It all depends on the recharge rate.

when recharge equals or exceeds discharge the fluid level remains static.

 

[Valveman]

I'm curious about how your well control works. I have several motors in my machine shop controlled by Variable Frequency Drives, AKA VFDs. Your situation must somehow sense demand which then tells the VFD to alter frequency so that the pump speed changes.
Most of the drives in my shop are controlled by the machine control but I do have a couple controlled by just me. The machine control is part of the expensive CNC control. The drives I control I understand and so control is no issue with me.
Having a well controlled by a VFD worries me because I may be locked into the device that senses demand and also locked into a particular VFD. VFDs are now so common that they have become really inexpensive. But the control interfaces vary quite a bit. If your VFD fails can you just buy another one with the same or better specs? And use it with the existing control?
The advantages of a 3 phase motor pumping the water, I think, can't be argued with from an electrical efficiency standpoint. But from a reliability standpoint I'm not so sure. Even though inverter power supplies, which is what VFDs are at heart, are very well understood, most of them are now made to satisfy a certain price and quality suffers because of this.
If the pump demand control interfaces with a generic VFD that would be great. A person could buy a generic VFD and just keep it for when the original one fails. Less that 100 bucks for a 2 HP VFD. But if the thing needed to be bought from a specific supplier then when the drive fails the cost will probably be a couple thousand.
Just my opinion of course after speaking to a couple electricians installing the new variable speed pump systems. So not a very big sample. Still, I'm curious.
Thanks,
Eric

VFD's are great for many processes. But they are an expensive Tar Baby for a home well pump system. The idea of constant pressure and variable flow is great. You just don't need a VFD to get that as a simple Cycle Stop Valve will do the same thing. The CSV makes even cheap pumps last much longer and works with normal single phase pumps.

 

[bdhsfz6]

If you have the space, multiple or large above ground storage tanks can also reduce the number of pump stop/start cycles. They can also boost water pressure on long pipe runs.

 

[Valveman]

If you have the space, multiple or large above ground storage tanks can also reduce the number of pump stop/start cycles. They can also boost water pressure on long pipe runs.

30+ years ago I also would have suggested a large pressure tank, or two if you could afford it and had the space. But even 20 pressure tanks are never adequate. A system has 20 tanks because an 80 gallon pressure tank only holds 25 gallons of water for a total of 500 gallons. 500 gallons of pressure tank draw down is bare minimum for a 500 GPM pump. It would take 60 tanks to keep cycling to an acceptable number. You cannot put in enough pressure tanks to eliminate cycling when small to medium amounts of water are being used. 60 tanks can't eliminate cycling for a 500 GPM pump anymore than 3 tanks can eliminate cycling for a small house well size pump. Bigger tanks just reduce the number of cycles, they can't eliminate cycling like a Cycle Stop Valve.

Also, pressure tanks actually cause a decrease in pressure. They cannot boost pressure. It takes a pump to do that. When a pressure tank is working with a 40/60 pressure switch, the pressure is good when the tank is almost full at 60 PSI. But the pressure gets lower and lower until it gets all the way down to 40 before the pump comes on, which is what boost the pressure. The larger or the more pressure tanks you have, the longer the pressure lingers low around 40 before the pump starts and pressure increases. This is why a Cycle Stop Valve working with a small pressure tank gives much stronger constant pressure. The little tank drains from 60 to 40 very quickly and the CSV holds 50 PSI for as long as any tap is open.

It doesn't sound like much difference but, 50 PSI constant being pushed from the pump and controlled by the CSV feels much stronger than when water from a tank is being "drawn" out as pressure decreases all the way down to 40 PSI. The CSV gives strong constant 50 PSI as long as any tap is open, which also completely eliminates pump cycling and all the problems that go with.

 

[Carl_NH]

Valveman, you are not wrong, but the context of the post by bhshb26 above is to use several 200–500-gallon tanks (non-pressurized) as reservoirs to draw from.

Yes this is a two pump system but the main well pump runs to fill say 200-300 gallons, then another pump on the tank supports the house demand. This can be a solution for low volume/output wells etc.