Well Drilled - Results

[Egon]

Idle time damage is dependant on the quality of water the pump sits in.

The flow rate is whatever the pump will produce at static water level. The amount should be determined by actual measurement or by using the pump flow curves. Accuracy of the flow curves depends on pump condition.

 

[Valveman]

So if the pump is putting out its max of 20GPM and the well static level never drops below let's say 350'. What is the GPM production of the well then? It would have to be higher than 20GPM. Maybe 25-30GPM?

Using a big compressor to blow the well will tell you how much water is coming into the well. But it won't tell you the pumping level of the well. The production is probably 20 GPM as the blow test indicates. But the pumping level at 20 GPM could be much higher than the total depth of the well. When pumping 20 GPM, if the pumping level stays at say 250', you could use a much smaller and less expensive pump than if you just plan for 470' because you do not know the actual pumping level.

 

[Valveman]

Is there any harm or damage to a well pump that sits idle for months at a time?

Actually as long as it doesn't get hit by lightning, the well is a good place to store a submersible. It stays at a constant temperature and is covered in water so the water in the motor doesn't leak out or evaporate through the skin.

You do want to turn the power off to the VFD however, as it stays powered up and uses power even when the pump is not running.

 

[Valveman]

The power coming in is single phase 230V but the controller converts it to 3 phase to the pump motor.

The pump has 21 stages

Yes if you use a VFD twice the size, it will convert single phase power to three phase, so it can run a three phase motor. The difference in efficiency from single phase to three phase is not enough to mention. But the three phase does let you use smaller wire. I have a customer right now who has been replacing a sensor or the VFD controller every year with his VFD system. He would love to replace the motor with a normal single phase so he would stop having so much trouble, but they trenched in the smaller wire underground and under the driveway, so he is stuck replacing the VFD every year until he decides to cut a new trench and put in wire that is a little larger.

 

[Valveman]

The pump doesn't hang from the pipe, it hangs from a poly rope that carries the weight. They will also install a torque arrestor on the pump to keep it from twisting the pipe off.

Pumps should never be held by a rope, as that will cause them to kick up sideways in the well and wear a hole in the casing, motor, or both. I would never use rope or cable in a well as that is just something that can come loose and cause a rat’s nest that will keep you from being able to pull the pump. If the pipe isn’t strong enough to hold the pump, use better pipe.

They will actually install 2 torque arrestors. One at the pump and one midway on the drop pipe.

Torque arrestors are also something that will swell and get hard, then you will not be able to get the pump out of the well. If VFD’s had as soft a start as the manufacturer claims, there would be no torque to arrest. The main problem with torque is wearing out the wire in the well. If you use double jacketed wire, tape it properly, and eliminate repetitive cycling, torque is not an issue.

 

[Valveman]

I would strongly recommend upgrading from brass to stainless check valves. The extra cost is going to be very small, maybe an extra $10 each. The brass ones installed with my original well were pretty corroded after 10 years.

Pulling the pump to replace them is north of a thou$and.

We don't use pitiless adaptors here so I don't know about that, but if a stainless one is available, I would opt for that also.

The installer may well tell you that it isn't necessary and that brass is good enough, but he doesn't have to pay for pulling the string and installing new ones, you pay him.

The reason brass check valves will corrode is because they are no longer really brass. The government made us take the lead out of all brass, and what is left is an alloy that has too much copper, which will turn green and corrode like the Statue of Liberty.

You should use a stainless check valve, and you will need a special one made for VFD type systems. The low flow and spinning action of the water coming from a VFD type pump makes the check valves rattle and wear quickly. There are special check valves made for VFD's that do not spin and rattle like normal checks. And I recommend having only one check valve at the pump, as any additional check valves will eventually start causing a water hammer on pump start. And any check valve above ground will cause a negative pressure in the underground pipe, which can draw in mud and contamination from the ditch.

 

[Valveman]

The flow rate is whatever the pump will produce at static water level.

The production of the well can be different volumes from different levels. When pumping only 10 GPM the pumping level may never get deeper than say 300'. But when pumping 20 GPM the pumping level may pull down to 470'. Testing the well at the maximum flow rate you will use can let you determine the actual pumping level, and therefore lets you determine the actual size of the pump needed.

I helped customers replace a couple of less than 2 year old Aquavars just yesterday. They couldn't handle the heat and dirt they get when installed outside. Make sure your VFD is in a clean (lint free) room with air conditioning, as they produce a lot of heat and need lots of clean air.

 

[Pettrix]

Valveman,

I appreciate the input but can you PLEASE stop slamming VFD's in every post you make? It's getting old. We get it, you don't sell VFD's, you sell CSVs and have a personal investment in seeing that CSV's sell.

I like the dialogue but the constant attack and slams on VFDs gets old.

I helped customers replace a couple of less than 2 year old Aquavars just yesterday. They couldn't handle the heat and dirt they get when installed outside. Make sure your VFD is in a clean (lint free) room with air conditioning, as they produce a lot of heat and need lots of clean air.

If VFD’s had as soft a start as the manufacturer claims

I have a customer right now who has been replacing a sensor or the VFD controller every year with his VFD system.
so he is stuck replacing the VFD every year .

 

[Pettrix]

Couldn't the sub cable be used to pull out a pump if needed? They are pretty strong, aren't they?

 

[Egon]

The production of the well can be different volumes from different levels. When pumping only 10 GPM the pumping level may never get deeper than say 300'. But when pumping 20 GPM the pumping level may pull down to 470'. Testing the well at the maximum flow rate you will use can let you determine the actual pumping level, and therefore lets you determine the actual size of the pump needed.

When pumping if the level stays static then the input should equal the pump rate. If the level doesn't stay static you don't know what the recharge rate is.

A cable or rope is often att he'd to the pump so fishing expeditions don't happen.