Pump Question

I have a drilled well with a 4 inch casing 96 ft deep. In 2002 I had to put in a new pump. Two weeks ago I ran out of water. We metered the pump and it seemed to be working. Last weekend we decided to raise the pump up a little and fill the casing with water. When we turned the pump on it would pump water directly out the top of the pump, and then would come to a stop. We decided the well was probably dry. This weekend I decided to turn on the pump again to see if it had recovered, and there was no water at all. I then raised the pump again and filled the casing with water and could get it to pump. Still not convinced that the well is dry I droped a line down the well and I could hear the weight hit water. I marked the string at that point, and continued to lower the weight to the bottom of the well. It showed I had 43 ft. of water. Why will the pump only pump water when I fill the casing up to the top?

Pumping dry?

I’m not sure where you are at, but here in North Phoenix, some of our wells go down 800 feet plus, and some only produce 4 of 5 gallons per minute. I wonder if it is possible that your pump is out pumping what your well can produce. I was told but a well company that I deal with, that I could put a valve on the out going water line, to slow the yield down. My well puts water into a storage tank, and then a jet pumps takes if from the tank into the house, so I can slow the yield down from the well.

I live in Central ILL. My well has a slow recovery, probably about 5 gallons a minute. The well set all week and never showed any sign of recovery. I then dropped a line down the well and could hear the weight hit water at about 43 ft. I could hear the pump running but nothing. If I fill the casing up with water it will pump, but I don't think it is pumping it dry. I was wondering if it is possible that filling the casing full of water is causing alot of head pressure,and that is helping the pump lift the water. Then when it pumps out enough water to remove some of the head pressure its not able to pump on its own. I have alot of iron in my water was wondering if maybe I could have a propeller in the pump that is not working. Thinking about getting a new pump.

At what height, in relation to the bottom of the well is the pump sitting?

The pump is setting around 2ft. off the bottom of the well.

I would pull it up another 3' and at the same time check the amperage draw while it is running, you may need a new pump.

Do you know what brand of pump it is?

It is an Aermotor T8-75. We raised it up 3ft. last weekend while it was pumping a stream about the size of a pencil, and it would keep pumping that small stream. If we filled the casing up it will pump a full garden hose stream.

It is Sunday but maybe one of the pump guys will be along and chime in...

BTW do you mean the drop pipe...or do you mean the casing.

Not sure what you are asking?

The casing holds the pump and drop pipe, the drop pipe is attatched to the pump and comes to the pitless adaptor, inside the casing.

Which did you fill with water. The drop pipe or casing.

It sounds as if your pump is plugged with rust. The passages may be filled and not able to pump enough head to pump when the water level drops. The other possibility is the impellers are broken.

If the pump is plugged you can take it apart and clean it out. A welding rod with a slight bend and an angle ground on to the end will allow you to clean out the impellers and diffusers. Using vinager or stronger acid will help finish the cleanning.

Your other option is to replace the pump.

I filled the casing with water. The drop pipe is holding water.

If I pull the pump to clean it I plan on replacing it. I put in a new pump in 2002, and we had alot of problems getting the old pump out and the new one back in, because of the tight fit. I would like to go to a 3" pump. Any sugestions what brand, and where to find one? Thanks, Steve

I don't like 3" pumps!

3" pumps are OK when absolutely necessary but they run 10,000 rpm as opposed to 1500 rpm and wear out faster.

Your screen on your existing pump could be plugged with iron but I doubt if if it pumps water when you fill the well with water. If you have 43 feet of water in the well and if the pump is set 3 ft. from the bottom tells me that you have approximately 40 ft. of usable storage water in the well. 40 ft. times 3/4 gallons per ft. tells me that you have at least 30 gallons of usable water in the well, assuming the well makes no additional water while pumping.

Therefore I think you have a pump problem. I recommend that you pull the pump and check it out. While it is of the well you may want to check the well for flow.

THE BELOW IS NOT GENERALLY FOR THE DO IT YOUR SELFER BUT IF YOU FEEL QUALIFIED READ ON BELOW, IF NOT I RECOMMEND THAT YOU CALL A RESPECTED QUALIFIED WELL DRILLER!

TO CHECK A WELL FOR FLOW: It's not an easy task, however if you want to attempt it yourself as follows. If the drop Pipe (pipe to the pump) is metal, run it back in the well (without the pump on it) to within 3' to 5' of well bottom. Rent a 150cfm air compressor and connect the 3/4" air hose to the drop pipe. Turn on the air slowly. Once the well unloads (blows all the stored water out) you can increase the air flow to where you get a steady water/air flow. Divert this water/air into a 4" Tee at the top of the casing. Measure this water/air flow in a measured 5 gallon bucket and time the flow with a stop watch. If it flows in excess of 5gpm the well is supplying what it was originally reported to you. If all is OK I suggest you install a new pump that will not exceed the well flow.

I'm not real happy about you being able to fill this well to the top. I don't know of any wells 4" or larger that have check valves in the bottom that would allow you to fill it to the top. So my conclusion would be that since you can fill it up, it is probably a low production well. If this is the case, you may have pumped the well down to the pump and nuked an impeller or two.

If you are looking for a better 3" pump than the Grundfos which turns 10,500 RPM's like Porky said, I have the Hydroflo 3" Submersible Pump which turns 3600 like a normal pump does.

bob...

Porky said:

3" pumps are OK when absolutely necessary but they run 10,000 rpm as opposed to 1500 rpm and wear out faster.

Click to expand...

I'm not aware of any 1500 RPM submersibles for 4" wells in the United States. What make/model would that be?

I am sure he meant 3500 RPM. Really the standard is 3600 RPM with 4% slip, which makes actual RPM of 3450.

Something I learned around a year ago. I always thought Grundfos's big claim to fame was the fact that all their parts are stainless. Shell, motor, impellers, check valve and spline. Not so in the 3" Grundfos pumps. I had the occasion to take one apart last year to see why it wouldn't develop the head it should and found one PLASTIC impeller nuked. They sure are proud of that pump for having plastic impellers.

bob...

Speed, those impellers are composite, not plastic. Since plastic and stainless steel would come apart at 10,000+ RPM, those composite must be pretty tough. Of course that is how they get the same water from an 11 pound pump as everyone else gets with a 35 pound pump and motor.

You could also grind the rust off an aircraft carrier with a 10,000 RPM Dremel tool, about as fast as with a heavy duty 3500 RPM grinder. The question is, which tool would last longer?

I didn't know that, but composite or not, they won't handle heat or any abrasive to speak of. That's why I had to take it apart. It went in a three inch well, ran until the water was clear, turned back on and nothing happened. The impeller became part of the diffuser in some kind or nuclear fission episode and that was all she wrote.

bob...